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35 | How do you create multiple blocks with minecraft addons? I've seen a question like this and I followed the directions they gave (Adding a blocks folder into behavior pack etc.), but I can't seem to get a result, it could be because I want to make 2 blocks (slime cyan and slime purple), OR it could also be because they weren't doing the right version because they said to add the component quot Register To Creative Menu quot and on bridge it doesn't even suggest that component (I know I said bridge but I'm not looking for a bridge tutorial). I just want to create 2 new blocks for Minecraft bedrock with only add ons, no special modding app, could anyone help me with this? I'm on Windows 10 edition. I'm using Minecraft Bedrock 1.16 |
35 | How can I check if player is an operator in Forge? In Minecraft Forge, I would like to know if there is any way to find out if a player currently has vanilla "OP" "Operator" status. I can't find a method that does this on the EntityPlayer Class. I'd like something like EntityPlayer player (EntityPlayer)sender if (player.getOpStatus) do some stuff |
35 | How do I use the Minecraft Coder Pack on Linux I downloaded the Minecraft coder pack to mod the game and decompile it, but how do I use it on Linux. Some sources seem to give specific directions, but they are not clear and they involve executing the .bat files. My Ubuntu does not recognize .bat file. How do I decompile a class file from changing a Minecraft version jar file to a zip and unzipping it? How do I decompile one of those class files using Minecraft coder pack? I have been wondering what at least some of the Minecraft source code looks like. |
35 | How can I read a portion of one Minecraft world file and write it into another? I'm looking to read block data from one Minecraft world and write the data into certain places in another. I have a Minecraft world, let's say "TemplateWorld", and a 2D list of Point objects. I'm developing an application that should use the x and y values of these Points as x and z reference coordinates from which to read constant sized areas of blocks from the TemplateWorld. It should then write these blocks into another Minecraft world at constant y coordinates, with x amp z coordinates determined based on each Point's index in the 2D list. The issue is that, while I've found a decent amount of information online regarding Minecraft world formats, I haven't found what I really need more of a breakdown by hex address of where what everything is. For example, I could have the TemplateWorld actually be a .schematic file rather than a world I just need to be able to read the bytes of the file, know that the actual block data starts always at a certain address (or after a certain instance of FF, etc.), and how it's stored. Once I know that, it's easy as pie to just read the bytes and store them. |
35 | Why Minecraft has such a terrible backward compatibility? For every release of Minecraft, even a minor release, is almost guaranteed to break some plugins or mod. Why is this so? I am asking this so that we could avoid the same architecture problem as Minecraft. I mean, why can't the upgrades also support previous version of minecraft? Minecraft requires an EXACT version number match in order to connect. I am pretty sure the protocol can be designed so that clients should ignore unsupported commands. For example, if there is new block introduced and the client doesn't understand it, they can just fall back to default dummy block so that players can still play but start seeing dummy wireframe block or so. Once they start seeing too much of wireframe blocks they know they should upgrade. |
35 | Where do I store (or how do I refer to) textures for custom blocks? I'm making my first foray into Minecraft modding on Ubuntu using Minecraft Forge. I'm finding it a little hard to get started as many of the tutorials seem to refer to older versions of Minecraft (e.g. that use the BaseMod base class, which now appears to be deprecated). I've created a simple block type package net.minecraft.block import net.minecraft.block. import net.minecraft.block.material. public class RolyBlock extends Block public RolyBlock(int par1, Material par2Material) super(par1, par2Material) and added the following static initialiser to the Block class public static final Block rolyBlock new RolyBlock(174, Material.rock) .setHardness(1.5F) .setResistance(10) .setStepSound(soundStoneFootstep) .setUnlocalizedName("rolyBlock") .setCreativeTab(CreativeTabs.tabBlock) .setTextureName("roly block") I created a 256x256 PNG file called roly block and placed it in Forge's MCP folder, in the same location as the other textures. However, when I start Minecraft (v. 1.6.5) via Eclipse, it is unable to locate the texture 2014 03 14 11 38 34 SEVERE Minecraft Client Using missing texture, unable to load minecraft textures blocks roly block.png I suspect this is because I put the texture in the directory forge mcp temp src minecraft assets minecraft textures (where I found the other textures) where this temp folder is presumably a decompiled version of the Minecraft 1.6.5 .jar file. I can't actually remember how I ended up with this folder, though. My question is how do I add a new texture to my Eclipse mod development environment? Must I rebuild a .jar each time, and if so how? Or can I have Minecraft load textures from a directory? (I'm a complete Minecraft newbie, so there are many things about the configuration dev environment for Minecraft that are confusing me. For example if I run recompile.py from Forge's MCP folder, I get a swathe of errors relating to IconRegister not being found.) |
35 | How do I make a Minecraft recipe that costs XP? I want to program a Minecraft client mod or server plugin that adds a recipe for making a Bottle o' Enchanting with the following ingredients 1 glass bottle 1 lvl of experience 1 Bottle o' Enchanting One possible implementation that I have thought of is to execute the command xp 1L player, but I am unsure how to invoke that command from my Java code. Is there a better way? How would you go about adding an experience requiring recipe to Minecraft? |
36 | Unity Particle System How to rotate particle effect? My Particle System creates a "puff" of smoke. When I rotate the particle system it doesn't rotate the effect, just the way the particle is shot. What I want to do is when I shoot a wall have it "puff" horizontal not vertical. And vertical when hitting floor. I want it to follow the normals of the surface I am raycasting to. My problem is that the texture doesn't turn with it's parent rotation. Do I need to write my own Custom Simulation Space to be able to rotate the effect? Assigning the transform of the parent does nothing. Prefab structure Particle Settings |
36 | Pygame surface rotation, rect rotation or sprite rotation? i seem to have a conceptual misunderstanding of the surface and rect object in pygame. I currently observe these objects this way Surface Just the loaded image rect the 'hard' representation of the ingame object (sprite). Used for simplifying object moment and collision detection sprite rect and surface grouped together What i want to do is rotate my sprite. The only available method i found for rotation is pygame.transform.rotate. How do i rotate the rectangle, or even better, the whole sprite? Below is the image of how i visualize this problem. |
36 | Rotate can I rotate an object to a target angle using Euler Angles? How do I rotate an object from its current angle to the desired angle in increments on 1 axis? The problem is the wraparound at 360 degrees What I have so far (Note pseudocode) double MaxSpeed 5 double CurrentAngle 170 double DesiredAngle 40 double Distance DesiredAngle CurrentAngle How do I calculate this value considering angle wraparound? CurrentAngle Mathd.clamp(Distance, MaxSpeed, MaxSpeed) Caps the rotation speed |
36 | Rotate final image with projection matrix I'm trying to use space in my shadow (depth) maps in a more efficient way. If I could freely rotate the final image I get with projection matrix I could save a lot of pixels, but I don't know if it is possible to do so. Is it? |
36 | How can obtain the relative orientation between two quaternions? How do I obtain the relative orientation given two orientations (represented by quaternions q0 and q1)? |
36 | Transform.forward having problems after rotation I have this script, void Update () float pitch, yaw, roll pitch Input.GetAxis ("Mouse Y") yaw Input.GetAxis ("Mouse X") roll Input.GetAxis ("Roll") transform.Rotate ( pitch, yaw, roll) if (Input.GetKey (KeyCode.W)) Rigid.AddRelativeForce (transform.forward 50) else if (Input.GetKey (KeyCode.S)) Rigid.AddRelativeForce ( transform.forward 50) else if (Input.GetKey (KeyCode.D)) Rigid.AddRelativeForce (transform.right 50) else if (Input.GetKey (KeyCode.A)) Rigid.AddRelativeForce ( transform.right 50) else Rigid.velocity Vector3.zero if (Input.GetKey (KeyCode.Space)) transform.rotation Quaternion.Euler (Vector3.zero) Rigid.velocity Vector3.zero Rigid.angularVelocity Vector3.zero My "Roll" is defined as 'q' and 'e' keys. "Rigid" is rigidbody object. I simply want to implement 6DoF on this cube, the pitch, yaw and roll works fine , but when it comes to movement it behaves in very unusual way after the object is rotated, I tried moving by using localPosition still no result. I also used relative torque for rotation but it resulted in worse, that is why rotation is controlled by transform.rotation not torque. I suppose I am not handling gimbal lock or something? Or am I doing it completely wrong? |
36 | Rotation in 3D space using Quaternion System Configuration I have two simulation systems (which I am going to call Sim A and Sim B) where I am going to spawn an entity created in Sim A inside Sim B. Expected outcome The entity created in Sim A appears in Sim B in the right position with the correct orientation. System Input The position of the entity created in Sim A received in Lat Long Alt format (it assumes WGS 84 spheroid) and the orientation in Euler angles. The Euler angles would help me to transform an entity from its world coordinate system to entity coordinate system by applying the Euler angles in the order of heading, pitch and yaw. Below is how it is documented. " The order of rotation is first, rotate about z by the angle psi (), then about the new y (y') by angle theta (T), then about the newest x (x'') by the angle phi (I). The positive direction of rotation about an axis is defined as clockwise when viewed toward the positive direction along the axis of rotation." However, in Sim B this rotation is defined in Quaternion and it assumes a perfect sphere for the world (not WGS 84). As a result, I have to convert Euler to Quaternion before sending the information to Sim B. I have achieved this by applying ZYX conversion (page A 11) given in here 2 . Challenge When I pass the position and orientation of an entity created in Sim A to Sim B ( Sim B uses ECEF system, so I do another conversion to go from LLA to ECEF), it appears in the correct LLA position but its orientation is incorrect (shown in the figure.). This can be fixed by adding some value to the pitch and roll but it is not mathematically sound. Also, these values might change (haven't tried) if you spawn the entity in a different location of the earth due to its shape. So, I would like to know the right way of correcting this issue (i.e. how to make the entity to stand upright). Assume that I can get the Up, Front and Right vector of the entity when it is spawned in Sim B. |
36 | CW CCW Rotation of a Vector Considering that I have a vector A, and after an arbitrary rotation I get vector B. I want to use this rotation operation in others vectors as well, but I'm having problems in doing that. My idea do that is to calculate the perpendicular vector C of the plane AB (by calculating AxB). This vector C is the axis that I'll need to rotate. To discover the angle I used the dot product between A and B, the acos of the dot product will return the lowest angle between A and B, the angle ang. The rotation I need to do is then rotate ang around the C axis. The problem is that I dont know if this rotation is a CW or CCW rotation, since the cos of the dot product does not give me information of the sign of the angle. There's a tip discover that in 2D ( A.x B.y A.y B.x) that you can use to discover if the vector A is at left right of vector B. But I dont know how to do this in 3D space. Can anyone help me? |
36 | Projectile Rotation During Flight (Tank Game) I have a tank firing projectiles into the air. I want the projectiles to be rotated relative to their position along their flight path. See the diagram I drew in the image below. At any given point I know the x and y of the projectile, z represents initial velocity, theta is also known. |
36 | From 3d rotation, snap to nearest 90 directions I have a 4x4 transformation matrix, made only from successive rotations and translations, and I'd like to "snap" my object to the "nearest" of the 24 orthogonal (multiples of 90 degree) rotations. I'm not sure how to think of the problem. Round each element of the upper 3x3 matrix to 1, 0, and 1 (cutting at .707)? I am pretty sure that would be too good to be true. Another possibility would be to convert to axis and rotation or quaternion, but would that make it simpler somehow? I'm not fluent in those manipulations. Any guidance most welcome! |
36 | Godot 3.0 Constant 2D Angular Velocity I am making a Top Down shooter in Godot 3.0 on Linux. I would like to have my character rotate to face the mouse pointer at a constant speed, and have rotation speed power ups that allow the player turn faster. So far, this is done by having a Position2D object called "Center" share the same position (but not be a child of) the player (below just called "Sprite"). The center always looks to the mouse, and the Sprite rotates with linear interpolation to eventually reach the same rotation as the "Center". The weight of linear interpolation is calculated by dividing the difference in rotation (in radians) by an arbitrary constant speed. Problem The speed of rotation increases as rotation occurs, or more specifically, the time it takes to reach the same rotation (a rotational difference of zero) becomes shorter over time. I have the following code extends Sprite onready var center get parent().get node("Center") var current time 0 var total time 0 var start rot 0 var end rot 0 func process(delta) center.look at(get global mouse position()) var amt 0 var theta abs(self.rotation center.rotation) var speed 0.05 total time theta speed start rot get rotation() end rot center.rotation if not total time 0 amt current time total time current time delta amt clamp(amt,0,1) var rot lerp(start rot,end rot,amt) center.rotation fmod(rot,(PI 2)) set rotation(fmod(rot,(PI 2))) get parent().get node("Control rotation").text str(int(self.rotation degrees)) get parent().get node("Control theta").text str(theta) get parent().get node("Control time").text str(total time) What am I doing wrong? |
36 | 2 Parts Object Material displays at 90degrees Material Mask will not rotate with object? Hi I have a 2 part issue. Part 1 I have a planet in Unreal, in the object editor it is aligned properly and the material displays correctly but in the game even with the rotation set to 0 it displays as being flipped 90 degrees to one side? Why is this happening and how do I make it display correctly? Part 2 The material for the planet has a mask on it to make it display day and night. However, when I attempt to manually rotate the object everything BUT the mask rotates which screws everything up. Why does the mask not rotate and how do I make it rotate with the rest for manual manipulation? |
36 | Does gimbal lock occur only when a combination of local and world rotation axis are used? In all the explanations I've seen of gimbal lock, they always refer to the fact that when performing a series of rotations on all axes, it is possible that one rotation might end up aligning an axis with another which causes us to lose a degree of freedom. This never made sense to me since a rotation around e.g. the LOCAL RIGHT axis will rotation the whole LOCAL BASIS, no alignment happens. The only explanation I've seen that made sense was this one by DMGregory where it clearly explains that gimbal lock occurs when we e.g. change the yaw using the local basis and the pitch using a world basis. My question is Is that the only scenario where gimbal lock occurs or am I missing something? I also thought that quaternions help avoid gimbal lock but again, I'm missing something here because it seems to occur regardless of the rotation representation method (euler quaternion). |
36 | Quaternion rotation is inverse of what I expect I'm trying to learn quaternions and decided to implement my own quaternion class. To test it I made a couple vertex shaders, one that gets a model matrix (calculated from the quaternion) and another that gets the rotation quaternion directly and rotates vertices in shader. I then feed these a quaternion that rotates around the Y axis t 10000 radians (t time) const rotation Quat.fromAxisAngle(new Vec3( 0, 1, 0 ), t 10000) The result surprises me because my model is rotating counter clockwise but I expected it to rotate clockwise, since the angle is increasing (checked it, quat's xyz increase with time). Rotation around the X or Z axes is also backwards. All translations as well as matrix rotations work as expected in my coordinate system. I suspect my formulas are wrong, and probably assume Z is forward. If I transpose my model matrix (or post multiply with it) it rotates as expected, which suggests it's a handedness problem. Where are my formulas wrong and how can I understand the math behind this? Details My matrices are column major in memory (to match GLSL's mat4). My coordinate system is X right, Y up, Z forward. My code Quaternion from axis angle function fromAxisAngle(axis Vec3, angle number, dest new Quat()) Quat angle 0.5 const sin Math.sin(angle) dest.x axis.x sin dest.y axis.y sin dest.z axis.z sin dest.w Math.cos(angle) return dest Note I noticed if I negate this quaternion's x, y and z, everthing works as expected. Is this the root cause? I thought quaternions didn't have handedness! Since this is actually just inverting the quaternion (and thus its rotation) I'm afraid I'm just patching over the root cause. I don't want to patch the issue, I want to fix my math! Matrix from quaternion toMat4(dest new Mat4()) Mat4 const x, y, z, w this const x2 x x const y2 y y const z2 z z const xx x x2 const xy x y2 const xz x z2 const yy y y2 const yz y z2 const zz z z2 const wx w x2 const wy w y2 const wz w z2 Notice matrix is column major Source https en.wikipedia.org wiki Quaternions and spatial rotation Quaternion derived rotation matrix dest.init( 1 (yy zz), xy wz, xz wy, 0, xy wz, 1 (xx zz), yz wx, 0, xz wy, yz wx, 1 (xx yy), 0, 0, 0, 0, 1, ) return dest Matrix vertex shader precision mediump float attribute vec3 aVertexPosition attribute vec2 aVertexUV uniform mat4 uModelMatrix uniform mat4 uViewMatrix uniform mat4 uProjectionMatrix varying vec2 vUV void main(void) vUV aVertexUV gl Position uProjectionMatrix uViewMatrix uModelMatrix vec4(aVertexPosition.xyz, 1.0) Quaternion vertex shader precision mediump float attribute vec3 aVertexPosition attribute vec2 aVertexUV struct Transform float scale vec3 translation vec4 rotation uniform Transform uModel uniform Transform uView uniform mat4 uProjection varying vec2 vUV Source https twistedpairdevelopment.wordpress.com 2013 02 11 rotating a vector by a quaternion in glsl vec3 rotateVector(vec4 quat, vec3 vec) return vec 2.0 cross(cross(vec, quat.xyz) quat.w vec, quat.xyz) void main(void) vUV aVertexUV vec3 world rotateVector(uModel.rotation, aVertexPosition uModel.scale) uModel.translation vec3 view rotateVector(uView.rotation, world uView.scale) uView.translation gl Position uProjection vec4(view, 1.0) |
36 | Fps independent rotation I'm trying in my game to have camera rotation speed idependent of fps. For keyboard it works without problems but not for mouse movoment. At 60 fps it works good but at 200 for example rotation is to slow. mouse dif is difference since last frame in pixels. Maybe thats a problem too, bigger screen resolution will rotate faster then smaller. My code const float rot speed u.GetRotationSpeed() returns 5.f float val 0 if(allow input ALLOW INPUT allow input ALLOW MOUSE) val float(mouse dif.x) 200 if(val gt rot speed dt) val rot speed dt else if(val lt rot speed dt) val rot speed dt u.rot val How can I make it fps independent? |
36 | Fps independent rotation I'm trying in my game to have camera rotation speed idependent of fps. For keyboard it works without problems but not for mouse movoment. At 60 fps it works good but at 200 for example rotation is to slow. mouse dif is difference since last frame in pixels. Maybe thats a problem too, bigger screen resolution will rotate faster then smaller. My code const float rot speed u.GetRotationSpeed() returns 5.f float val 0 if(allow input ALLOW INPUT allow input ALLOW MOUSE) val float(mouse dif.x) 200 if(val gt rot speed dt) val rot speed dt else if(val lt rot speed dt) val rot speed dt u.rot val How can I make it fps independent? |
36 | Quaternion rotations transforms from global to local space I am trying to solve this problem and getting no where, could really use some assistance. Rotation is defined as X (rotate left right), Y(rotate up down), Z(roll) Coordinates are X Forward backward, Y Left right, Z up down I have two objects in simulated space, both have galactic coordinates (XYZ) and a quaternion representing their rotation. ObjectA Coordinates 0.593 0 0 (directly ahead of ObjB) RotationQuat w 0, x 1, y 0, z 0 (Rotated 180 yaw, facing backwards) ObjectB Coordinates 0 0 0 RotationQuat w 1, x 0, y 0, z 0 (No rotation, facing towards ObjA) Given the above information, how do I translate ObjA's location into ObjB's local space? If ObjA fires at ObjB (or vise versa), I need to calculate which side will be hit. Forward, Aft, Port, Starboard, Ventral or Dorsal. My project is written entirely in C. Actually this is an old project, created by someone else that I am converting to using quaternions due to gimbal lock. Any advice? |
36 | Reconstruct Quaternion from 48 bit rotation data I'm trying to reverse an animation file from a commercial multiplayer game, whose format was recently updated. The problem lies within joint rotation information, which changed from a 128bit format to a 48 bit format. The old format actually was using a quaternion representation with 32 bit floats for each component (32 4 128 bit) The new format was probably added for quantization purposes (serving better multiplayer performance). I played around trying to apply an euler angle representation (3 x 16 bit integers or 3 x 16 bit half floats) but i failed miserably so I think it should be still a quaternion representation of some sort. I have located a model which has not changed at all structurally but obviously the model files have been updated to the newest format. So I do have the byte data, I know the correct rotation angles (again from game data) that correspond to those values as well as the quaternion values from the old version of the files. New Format Bytes Rotation(deg) X,Y,Z Quaternion 41 ED 3F ED 41 6D 0, 90.0, 89.99 0.5, 0.5, 0.5, 0.5 85 F7 2C A0 85 77 59.64, 90, 0 0.3516, 0.61347, 0.351634, 0.61347 AE CE FF BF FF 3F 180, 0, 18.54 0.98 0.16 0 0 40 ED BE 92 BE 12 0, 90,90 0.5, 0.5, 0.5, 0.5 DE 40 DA 42 CA 3C 1.017, 3.633, 4.091 0.009633918, 0.03154902, 0.03542599, 0.9988277 I'm currently searching the web for quaternion quantization techniques and I'm experimenting with different stuff, so if I find anything I'll make sure to update. Thanks in advance |
36 | How do I determine the forward right direction when I have the "up" vector? Unity I am trying to fix a gameobject for e.g. a cube (which i am using as a sensor) on my character. I need the cube to rotate (with orientation control from the inspector I have a public quaternion rotation variable set). I have identified 3 vertices using ray cast to fix my sensor onto the character. I already have determined the normal of these vertices which will be the "up" direction of the cube. I am wondering how I can determine the forward right vector to use in the LookRotation() function. I need to basically be able to rotate the cube ON the character even as the character moves on animation. This is my code, and as of now there is no rotation happening. I'm sure I am missing something and would really appreciate help. I really hope this is enough explanation. using System.Collections using System.Collections.Generic using UnityEngine public class orientation MonoBehaviour importing from Vertex Finder Script to use InterpolatedNormalInWorldSpace value private VertexFinder script public Transform target to edit orientation of sensor in Unity Inspector public Quaternion rotation edit Start is called before the first frame update void Start() script GetComponent lt VertexFinder gt () Quaternion TurretLookRotation(Vector3 approximateForward, Vector3 exactUp) Quaternion rotateZToUp Quaternion.LookRotation(exactUp, approximateForward) Quaternion rotateYToZ Quaternion.Euler(90f, 0f, 0f) return rotateZToUp rotateYToZ Update is called once per frame void Update() Vector3 relativePos target.position transform.position aligning axes of sensor to z axis and y axis respectively Quaternion rotation1 TurretLookRotation(relativePos, script.interpolatedNormalInWorldSpace) setting rotation of sensor to values entered in Inspector with respect to the above aligned axes transform.rotation rotation1 rotation edit |
36 | Rotating the playing field. (MonoGame) My maths isn't as good as it should be, I need to pick up some reference books on Trig. Could someone give me an idea of the maths if I wanted to revolve many sprites around a central point? It's a 2D system in MonoGame. I'm going to try to describe the scenario, I can't think of anything quite like it to reference. Imagine a game screen, you are looking down on the world, with my character in the middle, my character sprite will never change, but if I turn left or right I want everything else to rotate around the central point. Of course every sprite will have to be moved, and also rotate to account for the spin. Can someone point me in the right direction? Thanks. |
36 | How do I determine the forward right direction when I have the "up" vector? Unity I am trying to fix a gameobject for e.g. a cube (which i am using as a sensor) on my character. I need the cube to rotate (with orientation control from the inspector I have a public quaternion rotation variable set). I have identified 3 vertices using ray cast to fix my sensor onto the character. I already have determined the normal of these vertices which will be the "up" direction of the cube. I am wondering how I can determine the forward right vector to use in the LookRotation() function. I need to basically be able to rotate the cube ON the character even as the character moves on animation. This is my code, and as of now there is no rotation happening. I'm sure I am missing something and would really appreciate help. I really hope this is enough explanation. using System.Collections using System.Collections.Generic using UnityEngine public class orientation MonoBehaviour importing from Vertex Finder Script to use InterpolatedNormalInWorldSpace value private VertexFinder script public Transform target to edit orientation of sensor in Unity Inspector public Quaternion rotation edit Start is called before the first frame update void Start() script GetComponent lt VertexFinder gt () Quaternion TurretLookRotation(Vector3 approximateForward, Vector3 exactUp) Quaternion rotateZToUp Quaternion.LookRotation(exactUp, approximateForward) Quaternion rotateYToZ Quaternion.Euler(90f, 0f, 0f) return rotateZToUp rotateYToZ Update is called once per frame void Update() Vector3 relativePos target.position transform.position aligning axes of sensor to z axis and y axis respectively Quaternion rotation1 TurretLookRotation(relativePos, script.interpolatedNormalInWorldSpace) setting rotation of sensor to values entered in Inspector with respect to the above aligned axes transform.rotation rotation1 rotation edit |
36 | THREE.JS why is the rotation only applied on the last axis used? my function function rotateAroundWorldAxis2(object, radians1, radians2) object.rotWorldMatrix.makeRotationX(radians1).makeRotationZ(radians2) object.rotWorldMatrix old code for Three.JS pre r54 rotWorldMatrix.multiply(object.matrix) new code for Three.JS r55 object.rotWorldMatrix.multiply(object.matrix) pre multiply object.matrix.copy( object.rotWorldMatrix ) old code for Three.js pre r49 object.rotation.getRotationFromMatrix(object.matrix, object.scale) old code for Three.js pre r59 object.rotation.setEulerFromRotationMatrix(object.matrix) code for r59 object.rotation.setFromRotationMatrix(object.matrix) my object was initialized like this object.rotWorldMatrix new THREE.Matrix4() |
36 | Rotate around an axis function for euler angles representation For a 3d game i need a function to rotate an euler representation around an arbitary axis by an angle. For example an object is rotated with euler angles (0,90,0). Now the object should be rotated by 100 degrees around the axis (0,1,0). The resulting angle will be (0,190,0) using rotation order YXZ. In this case I can add the angle to the euler value of the axis, however for an arbitary axis this will not work. Problem with Quaternions amp Rotation matrices With these representations the resulting rotations will always be smaller that 180 for each axis. I need the rotation to be lerped afterwards for example from (0,0,0) to (0,720,0). Basically I am searching for a way to display euler angles like most of the 3D editors. When you rotate an object around any arbitary axis rotation might be larger than 360 in the editor, like (420,720,15). |
36 | How to convert relative position of child to parent into an absolute position? I am modifying a game that stores object positions with a 3d vector x, y, z and rotation as a 3d vector with degree angles x, y, z . I want to place an object in relation to a parent object accounting for its rotation. I do not have access to the game code, so I have to provide a position of the child as an absolute position. For example, I would like to place a child object at a relative position 50, 0, 100 50 units along the x axis and 100 units up the z axis from the parent's position. Assuming the parent object is currently at position 0, 0, 0 with rotation 0, 0, 0 the resulting absolute position for the child object would be simply 50, 0, 100 . But, if the parent has a position of 0, 0, 0 and a rotation of 0, 0, 90 , the child's absolute position would be 0, 50, 100 . What would be the transformation function that, given the absolute parent position, parent rotation, and relative child position, outputs the absolute position of the child (taking into account all three axes of rotation)? |
36 | Transform inertia tensor using quaternion I have inertia tensor T in body coordinates and quaternion q for the body. I know I can transform T to world coordinate by converting quaternion to rotation matrix R and then use the relation (R T R T). However this seems unnecessarily expensive and unwieldy (especially if you are doing this often). So my question is How do I transform inertia tensor from body to world coordinate directly using quaternion and without having to generate rotation matrix from quaternion? |
36 | How to convert relative position of child to parent into an absolute position? I am modifying a game that stores object positions with a 3d vector x, y, z and rotation as a 3d vector with degree angles x, y, z . I want to place an object in relation to a parent object accounting for its rotation. I do not have access to the game code, so I have to provide a position of the child as an absolute position. For example, I would like to place a child object at a relative position 50, 0, 100 50 units along the x axis and 100 units up the z axis from the parent's position. Assuming the parent object is currently at position 0, 0, 0 with rotation 0, 0, 0 the resulting absolute position for the child object would be simply 50, 0, 100 . But, if the parent has a position of 0, 0, 0 and a rotation of 0, 0, 90 , the child's absolute position would be 0, 50, 100 . What would be the transformation function that, given the absolute parent position, parent rotation, and relative child position, outputs the absolute position of the child (taking into account all three axes of rotation)? |
36 | UE4 Event Tick and getting Forward Vector I'm trying to make a game where my character rotates towards cursor (that works). He can choose between a few weapons (also works). One of the weapons works like a machine gun. My idea was to make a simple solution with Event tick gt gate (opened by pulling LBM and closed by releasing it) gt gate (closed after firing and opened after some delay) gt spawning projectile which leads to a sequence that closes opens the second gate. It doesn't work perfectly. The projectile spawns with the right scale and location, but the rotation is always pointing straight forward. If the exactly same blueprint is attached to anything else (straight up to the LMB pull or a timer), it works perfectly. However, doing the LMB pull defeats the whole purpose, as it's not a machine gun any more, and timer... is less then perfect I believe. I liked my solution using gates but it just doesn't want to work. For example, this bit works with no problem (even though the spawning and rotation code is literally copy pasted) Does anyone have an idea on how to fix this? |
36 | AABB of rotated sprite? Say I have a sprite. Its AABB is easy to find since I know the width and height. Say I rotate it 45 degrees, I don't think the AABB would be big enough to cover it, so I need a new AABB. How can I calculate the bounding rectangle of a rotated rectangle (given a center point, an angle, and its width and height)? Note that OpenGL does the rotation so I do not have access to the vertex information. What I'm trying to do is get AABBs so I can do 2D culling for rendering. Thanks |
36 | How to expand the limit of screen mouse access for FPS side rotation I started coding in Godot and i have a working FPS controller but the problem is that when i move my mouse sideways , it cannot move my sight beyinid that side of my screen , in other words the movement of my charecter is limited by the size of my screen , how to prevent this Rotation code func input(event) if event is InputEventMouseMotion head.rotate y(deg2rad(event.relative.x mouseSensitivity)) camera.rotate x(deg2rad(event.relative.y mouseSensitivity)) |
36 | XNA Rotating a Rectangle? I am in the process of making a giant shooter game and I have got to the point where I needed to use rectangles to detect bullets and giants hitting the player. I did that however, if you look at this image It shows the giant and the players rectangle, as you can see they are not rotating with the player, any idea how to fix this? Also yes I know they are no the same size as the sprites, that is because I set the size as they were to big before. Thanks for any help ) |
36 | from normal to rotation matrix (i'm on OPENGL) i have a mesh O (object) and a mesh T (terrain). i know a single triangle in T and i want to orient O to be aligned to that triangle (torate O to align to T in that point). i have only the normal in the triangle. how can i achive the roation matrix? i have thought this algorithm pseudocode float normal2rotation(Vector3D normal) angleX Vector3D.angleBetween(normal, Vecto3D.Axis3D.X) angleY Vector3D.angleBetween(normal, Vecto3D.Axis3D.Y) angleZ Vector3D.angleBetween(normal, Vecto3D.Axis3D.Z) float result angleX, angleY, angleZ return result but it does not give me the desired result. |
36 | Find out which way to rotate based on current rotation and final rotation I have one object that I want to rotate to a certain angle with 'smooth' rotation. I looked up on how to solve that and I came up with this enter image description here But how do I know in what way to rotate, positive or negative? According the the picture on ex. 1, I need to rotate positively because it is the closest way for me to rotate. And on the second it is the negative way. But how do I know this? I've tried several solutions but I can't seem to find anything that is correct. |
36 | How to find optimal perpendicular axis of rotation vector to draw arrows? I am drawing lines on the screen. Each line has a point (x,y,z) and a direction (u,v,w). I want to draw arrow heads on these lines, like two lines that start from (x,y,z) and leave at a 15 degree angle. I know how to draw these arrow head lines. I do this by rotating (u,v,w) by 15 degrees on some axis of rotation which is perpendicular to (u,v,w). The problem is the axis of rotation I am using is not making all my graphs look good. Basically I'm given a unit vector (u,v,w). If w 1, then u and v are 0 and I just use (1,0,0) which is a unit vector and perpendicular to (u,v,w). If that is not the case, then I use (v, u, 0) which is not a unit vector but is perpendicular. Then I normalize it. The norm won't be 0, since w lt 1 which means u 2 v 2 ! 0. This gives ok results. But some tests, the arrow head lines look a bit messed up, or not even looking like a 15 degree angle from the main line. Does anyone know a good way to find a good perpendicular unit vector to (u,v,w) so the results will always look good? Thanks |
36 | Quaternion rotation is inverse of what I expect I'm trying to learn quaternions and decided to implement my own quaternion class. To test it I made a couple vertex shaders, one that gets a model matrix (calculated from the quaternion) and another that gets the rotation quaternion directly and rotates vertices in shader. I then feed these a quaternion that rotates around the Y axis t 10000 radians (t time) const rotation Quat.fromAxisAngle(new Vec3( 0, 1, 0 ), t 10000) The result surprises me because my model is rotating counter clockwise but I expected it to rotate clockwise, since the angle is increasing (checked it, quat's xyz increase with time). Rotation around the X or Z axes is also backwards. All translations as well as matrix rotations work as expected in my coordinate system. I suspect my formulas are wrong, and probably assume Z is forward. If I transpose my model matrix (or post multiply with it) it rotates as expected, which suggests it's a handedness problem. Where are my formulas wrong and how can I understand the math behind this? Details My matrices are column major in memory (to match GLSL's mat4). My coordinate system is X right, Y up, Z forward. My code Quaternion from axis angle function fromAxisAngle(axis Vec3, angle number, dest new Quat()) Quat angle 0.5 const sin Math.sin(angle) dest.x axis.x sin dest.y axis.y sin dest.z axis.z sin dest.w Math.cos(angle) return dest Note I noticed if I negate this quaternion's x, y and z, everthing works as expected. Is this the root cause? I thought quaternions didn't have handedness! Since this is actually just inverting the quaternion (and thus its rotation) I'm afraid I'm just patching over the root cause. I don't want to patch the issue, I want to fix my math! Matrix from quaternion toMat4(dest new Mat4()) Mat4 const x, y, z, w this const x2 x x const y2 y y const z2 z z const xx x x2 const xy x y2 const xz x z2 const yy y y2 const yz y z2 const zz z z2 const wx w x2 const wy w y2 const wz w z2 Notice matrix is column major Source https en.wikipedia.org wiki Quaternions and spatial rotation Quaternion derived rotation matrix dest.init( 1 (yy zz), xy wz, xz wy, 0, xy wz, 1 (xx zz), yz wx, 0, xz wy, yz wx, 1 (xx yy), 0, 0, 0, 0, 1, ) return dest Matrix vertex shader precision mediump float attribute vec3 aVertexPosition attribute vec2 aVertexUV uniform mat4 uModelMatrix uniform mat4 uViewMatrix uniform mat4 uProjectionMatrix varying vec2 vUV void main(void) vUV aVertexUV gl Position uProjectionMatrix uViewMatrix uModelMatrix vec4(aVertexPosition.xyz, 1.0) Quaternion vertex shader precision mediump float attribute vec3 aVertexPosition attribute vec2 aVertexUV struct Transform float scale vec3 translation vec4 rotation uniform Transform uModel uniform Transform uView uniform mat4 uProjection varying vec2 vUV Source https twistedpairdevelopment.wordpress.com 2013 02 11 rotating a vector by a quaternion in glsl vec3 rotateVector(vec4 quat, vec3 vec) return vec 2.0 cross(cross(vec, quat.xyz) quat.w vec, quat.xyz) void main(void) vUV aVertexUV vec3 world rotateVector(uModel.rotation, aVertexPosition uModel.scale) uModel.translation vec3 view rotateVector(uView.rotation, world uView.scale) uView.translation gl Position uProjection vec4(view, 1.0) |
36 | I'm rotating an object on two axes, so why does it keep twisting around the third axis? I see questions come up quite often that have this underlying issue, but they're all caught up in the particulars of a given feature or tool. Here's an attempt to create a canonical answer we can refer users to when this comes up with lots of animated examples! ) Let's say we're making a first person camera. The basic idea is it should yaw to look left amp right, and pitch to look up amp down. So we write a bit of code like this (using Unity as an example) void Update() float speed lookSpeed Time.deltaTime Yaw around the y axis using the player's horizontal input. transform.Rotate(0f, Input.GetAxis("Horizontal") speed, 0f) Pitch around the x axis using the player's vertical input. transform.Rotate( Input.GetAxis("Vertical") speed, 0f, 0f) or maybe Construct a quaternion or a matrix representing incremental camera rotation. Quaternion rotation Quaternion.Euler( Input.GetAxis("Vertical") speed, Input.GetAxis("Horizontal") speed, 0) Fold this change into the camera's current rotation. transform.rotation rotation And it mostly works, but over time the view starts to get crooked. The camera seems to be turning on its roll axis (z) even though we only told it to rotate on the x and y! This can also happen if we're trying to manipulate an object in front of the camera say it's a globe we want to turn to look around The same problem after a while the North pole starts to wander away to the left or right. We're giving input on two axes but we're getting this confusing rotation on a third. And it happens whether we apply all our rotations around the object's local axes or the world's global axes. In many engines you'll also see this in the inspector rotate the object in the world, and suddenly numbers change on an axis we didn't even touch! So, is this an engine bug? How do we tell the program we don't want it adding extra rotation? Does it have something to do with Euler angles? Should I use Quaternions or Rotation Matrices or Basis Vectors instead? |
36 | Godot Quaternion slerp is altering initial rotation of an object I have a player that shoots a rocket. If the rocket has a target, I use a quaternion slerp to make it home in on that target. Free firing the rocket goes directly forwards as expected. Setting a tracking speed of 1 homes directly towards the target as expected. But for some reason if I set tracking speed to less than 1, the rocket's initial direction becomes (0 0, 1) no matter where the ship is pointing and then proceeds to rotate towards the target. Code below. var transformed rotation Transform global transform.looking at(target.global transform.origin, Vector3.UP) var new rotation Quat Quat(global transform.basis).slerp(transformed rotation.basis, tracking speed) set global transform(Transform(new rotation, global transform.origin)) |
36 | Does gimbal lock occur only when a combination of local and world rotation axis are used? In all the explanations I've seen of gimbal lock, they always refer to the fact that when performing a series of rotations on all axes, it is possible that one rotation might end up aligning an axis with another which causes us to lose a degree of freedom. This never made sense to me since a rotation around e.g. the LOCAL RIGHT axis will rotation the whole LOCAL BASIS, no alignment happens. The only explanation I've seen that made sense was this one by DMGregory where it clearly explains that gimbal lock occurs when we e.g. change the yaw using the local basis and the pitch using a world basis. My question is Is that the only scenario where gimbal lock occurs or am I missing something? I also thought that quaternions help avoid gimbal lock but again, I'm missing something here because it seems to occur regardless of the rotation representation method (euler quaternion). |
36 | What is an efficient way to get a look at direction from either a quaternion or a transformation matrix? So, I have an object in my custom engine (C ), with a column major transform in world space. I'm using a package that takes a look at direction as an input. What's the most efficient way to get a look at direction from this transform? Do I extract the rotation matrix? Do I try to extract a quaternion? |
36 | How to expand the limit of screen mouse access for FPS side rotation I started coding in Godot and i have a working FPS controller but the problem is that when i move my mouse sideways , it cannot move my sight beyinid that side of my screen , in other words the movement of my charecter is limited by the size of my screen , how to prevent this Rotation code func input(event) if event is InputEventMouseMotion head.rotate y(deg2rad(event.relative.x mouseSensitivity)) camera.rotate x(deg2rad(event.relative.y mouseSensitivity)) |
36 | from normal to rotation matrix (i'm on OPENGL) i have a mesh O (object) and a mesh T (terrain). i know a single triangle in T and i want to orient O to be aligned to that triangle (torate O to align to T in that point). i have only the normal in the triangle. how can i achive the roation matrix? i have thought this algorithm pseudocode float normal2rotation(Vector3D normal) angleX Vector3D.angleBetween(normal, Vecto3D.Axis3D.X) angleY Vector3D.angleBetween(normal, Vecto3D.Axis3D.Y) angleZ Vector3D.angleBetween(normal, Vecto3D.Axis3D.Z) float result angleX, angleY, angleZ return result but it does not give me the desired result. |
36 | How can I keep the clicked point under the mouse when rotating? (GLM) I have a spherical mesh of radius 1, centered at (0,0,0) in world coordinates. I want to rotate the sphere so that the clicked point remains under the mouse at all times. However, I cannot find an algorithm that does this. The clicked point always drifts away from the mouse. My current algorithm does the following Cast a ray to a sphere of radius 1. Find intersection point in world coordinates (Pa). After the mouse is moved, cast another ray and find a new intersection point. (Pb) since both those 3D points are on a sphere of radius one, centered at the origin, they should have length 1 but just in case I normalize them both. Find the rotation axis by doing Pa x Pb. Normalize the resulting axis axis glm cross(Pa,Pb) axis glm normalize(axis) Find the angle by doing arccosine on the dot product float angle glm acos(glm dot(Pa,Pb)) Build a rotation matrix from the axis and angle mat4 rotation glm rotate(glm degrees(angle),axis) lt This was the mistake glm degrees is not needed Multiply the existing model matrix by that calculated matrix modelMatrix rotation modelMatrix The rotations are correct but the clicked point does not stay under the mouse (I am checking by drawing a black square point on the sphere texture when the drag starts). If I click and drag to the right, the initially clicked point drifts to the left (lags). |
36 | Tank movement based on track speeds I want a system, where a tank moves and rotates based on the speeds I give him for the two tracks, for example, if I give the left track a speed of 1 and the right one a speed of 1, then I want the tank to stay still and rotate right, while if I give the left track 1 and the right track 0.5, I want it to rotate, but at the same time move forward Of course the speeds will be between 1 and 1 |
36 | Rotating the playing field. (MonoGame) My maths isn't as good as it should be, I need to pick up some reference books on Trig. Could someone give me an idea of the maths if I wanted to revolve many sprites around a central point? It's a 2D system in MonoGame. I'm going to try to describe the scenario, I can't think of anything quite like it to reference. Imagine a game screen, you are looking down on the world, with my character in the middle, my character sprite will never change, but if I turn left or right I want everything else to rotate around the central point. Of course every sprite will have to be moved, and also rotate to account for the spin. Can someone point me in the right direction? Thanks. |
36 | How do I rotate shoulder bone up and down using Rotate and Space.World independend on model orientation I wanted to move my character's arms up and down in a straight way. The Rotation Gizmo tool can do exactely that. Playing with the wheel of the Rotation Gizmo tool in the attached screenshot (marked with red arrows in my screenshot), I could move the arms down in a straight way I can do the same using the following script using System.Collections using System.Collections.Generic using UnityEngine public class MyPlayer MonoBehaviour public Transform Shoulder private Quaternion Rotation private float f 0f private void OnGUI() if (GUI.Button(new Rect(0, 70, 50, 30), quot quot )) f 1 Shoulder.Rotate( f, 0, 0, Space.World) This works perfectly fine, but no longer when I rotate the main model ( the parent of the shoulder). How could I make this script independend on the main transform's orientation? Thank you! Edit I would guess that I have to take the main transform ( parent) orientation into account in order to subtract its global rotation from the calculations, but not really knowing which values I should choose, I didn't find the correct formula. However, FYI, I tried the following using System.Collections using System.Collections.Generic using UnityEngine public class MyPlayer MonoBehaviour public Transform Shoulder public Transform Mother private float f 0f private void OnGUI() if (GUI.Button(new Rect(0, 70, 50, 30), quot quot )) f 1 f Mother.transform.rotation.eulerAngles.x Shoulder.Rotate( f, 0, 0, Space.World) |
36 | How do I determine the forward right direction when I have the "up" vector? Unity I am trying to fix a gameobject for e.g. a cube (which i am using as a sensor) on my character. I need the cube to rotate (with orientation control from the inspector I have a public quaternion rotation variable set). I have identified 3 vertices using ray cast to fix my sensor onto the character. I already have determined the normal of these vertices which will be the "up" direction of the cube. I am wondering how I can determine the forward right vector to use in the LookRotation() function. I need to basically be able to rotate the cube ON the character even as the character moves on animation. This is my code, and as of now there is no rotation happening. I'm sure I am missing something and would really appreciate help. I really hope this is enough explanation. using System.Collections using System.Collections.Generic using UnityEngine public class orientation MonoBehaviour importing from Vertex Finder Script to use InterpolatedNormalInWorldSpace value private VertexFinder script public Transform target to edit orientation of sensor in Unity Inspector public Quaternion rotation edit Start is called before the first frame update void Start() script GetComponent lt VertexFinder gt () Quaternion TurretLookRotation(Vector3 approximateForward, Vector3 exactUp) Quaternion rotateZToUp Quaternion.LookRotation(exactUp, approximateForward) Quaternion rotateYToZ Quaternion.Euler(90f, 0f, 0f) return rotateZToUp rotateYToZ Update is called once per frame void Update() Vector3 relativePos target.position transform.position aligning axes of sensor to z axis and y axis respectively Quaternion rotation1 TurretLookRotation(relativePos, script.interpolatedNormalInWorldSpace) setting rotation of sensor to values entered in Inspector with respect to the above aligned axes transform.rotation rotation1 rotation edit |
36 | Rotating Object parallel to other object I try to rotate objects in the same direction as a reference object. Normaly this would be easy object1.rotation reference.rotation But the same rotation can be expressed with different vectors (0, 45, 270) is the same as (0, 225, 90) (0, 0, 270) is the same as (0, 180, 90) In my case the final rotation should account for this. The reference object has a rotation of (0, 45, 270) Object1 Should Rotate from (0, 45, 270) to (0, 0, 270) Object2 Should Rotate from (0, 225, 90) to (0, 180, 90) How can i calculate this? Im using unity if this is any help. |
36 | Quaternion rotations transforms from global to local space I am trying to solve this problem and getting no where, could really use some assistance. Rotation is defined as X (rotate left right), Y(rotate up down), Z(roll) Coordinates are X Forward backward, Y Left right, Z up down I have two objects in simulated space, both have galactic coordinates (XYZ) and a quaternion representing their rotation. ObjectA Coordinates 0.593 0 0 (directly ahead of ObjB) RotationQuat w 0, x 1, y 0, z 0 (Rotated 180 yaw, facing backwards) ObjectB Coordinates 0 0 0 RotationQuat w 1, x 0, y 0, z 0 (No rotation, facing towards ObjA) Given the above information, how do I translate ObjA's location into ObjB's local space? If ObjA fires at ObjB (or vise versa), I need to calculate which side will be hit. Forward, Aft, Port, Starboard, Ventral or Dorsal. My project is written entirely in C. Actually this is an old project, created by someone else that I am converting to using quaternions due to gimbal lock. Any advice? |
36 | How do i make enemy tank to follow and face player tank? I'm creating tank game demo , in game i want enemy tank to always face toward the player tank. I already check look at() function but it will face immediately, i don't want that. I want enemy tank to slowly rotate toward player. What i'hv done so fare is MainWindow.gd extends Node2D func ready() Tank2.loadPlayer1( Tank1) pass EnemyTank.gd extends KinematicBody2D var rotSpeed 0.3 var player1 var speed 30 var velocity Vector2() func ready() pass func loadPlayer1(obj) player1 obj func process(delta) if player1 ! null velocity Vector2() var rot dir (player1.position position).angle() rotation rotSpeed rot dir delta velocity Vector2(0,0).rotated(rotation) move and slide(velocity) pass My Result is Enemy Tank (red) keep rotating Does anyone know how do i fix this? Thank you |
36 | Rotating and pitching a turret I am new to game development and I was trying to build a turret model, and control it through lua script in shiva3d. I can rotate it around the y axis which is no problem, but when it comes to pitching, I am not sure how to do that in a way which is independent of the Y rotation, for example, in the default position, rotating with a positive value around X aims upwards, which is what I expect. when I rotate it by 180 degrees around Y, the positive rotation around X aims downwards towards the ground instead of upwards. on the other hand, if I rotate by 90 degrees, the turret rotates around it self as if its rolling... I am not sure what to look for in order to understand how rotation in a 3d world should happen, so any pointers on that would be much appreciated |
36 | Increasing the rotation angle on a quaternion makes the rotation stop at a certain angle I'm using the following code to change the rotation of an object Quaternion rot getRotation() setRotation(make quaternion axis angle(rot.v,rotationSpeed dt) rot) This code works as expected until a certain angle where it suddenly stops. Why does it stop? |
36 | Programmatically determine UVs by rotating a plane along X axis I'm having a math brainfart while trying to solve what might be a simple problem. I've got a plane in 3d space (it's actually the face of a 10 sided die) Coordinates x,y,z Point top 0,0,1 Point left Sin (2pie9 10), Cos(2pie9 10), 0.1 .5878,.809,.1 Point right Sin (2pie 10) , Cos(2pie 10), 0.1 .5878,.809,.1 Point bot 1,0, 0.1 If you project that out, it's a plane with the top leaning back away from you, and the bottom closer to you. I'm trying to automatically build a UV map of that face to put a texture on, so think I should rotate it around the x asix so that it's only in 2D, then scale that to best fill up a 256x256 texture. I'm doing this in Three.JS for a canvas app. Is this the right approach? In this example http wecreategames.com games DiceBoard ( die creation code is in http wecreategames.com games DiceBoard die10.js ), I'm estimating the UVs by Build UVs scope.faceUvs scope.faceVertexUvs for (var f 0 f lt numHalfFaces f ) var faceuv new THREE.UV(.2, .6), new THREE.UV(.5, .75), new THREE.UV(.8, .6), new THREE.UV(.5, .2) scope.faceUvs 0 .push(new THREE.UV(0, 1)) scope.faceVertexUvs 0 .push(faceuv) But when I view on an iPhone or Android, it shows weird screen artifacts... I'm thinking because the UVs aren't exact. I think I'd apply some function like this (where andDist is an angle) rx x ry (y Math.cos(angDist)) (z Math.sin(angDist)) rz (y Math.sin(angDist)) (z Math.cos(angDist)) But, I'm not sure how to get the angle that the face is inclined at. Any suggestions? Or, are those white screen artifacts due to something else I've overlooked? |
36 | Programmatically determine UVs by rotating a plane along X axis I'm having a math brainfart while trying to solve what might be a simple problem. I've got a plane in 3d space (it's actually the face of a 10 sided die) Coordinates x,y,z Point top 0,0,1 Point left Sin (2pie9 10), Cos(2pie9 10), 0.1 .5878,.809,.1 Point right Sin (2pie 10) , Cos(2pie 10), 0.1 .5878,.809,.1 Point bot 1,0, 0.1 If you project that out, it's a plane with the top leaning back away from you, and the bottom closer to you. I'm trying to automatically build a UV map of that face to put a texture on, so think I should rotate it around the x asix so that it's only in 2D, then scale that to best fill up a 256x256 texture. I'm doing this in Three.JS for a canvas app. Is this the right approach? In this example http wecreategames.com games DiceBoard ( die creation code is in http wecreategames.com games DiceBoard die10.js ), I'm estimating the UVs by Build UVs scope.faceUvs scope.faceVertexUvs for (var f 0 f lt numHalfFaces f ) var faceuv new THREE.UV(.2, .6), new THREE.UV(.5, .75), new THREE.UV(.8, .6), new THREE.UV(.5, .2) scope.faceUvs 0 .push(new THREE.UV(0, 1)) scope.faceVertexUvs 0 .push(faceuv) But when I view on an iPhone or Android, it shows weird screen artifacts... I'm thinking because the UVs aren't exact. I think I'd apply some function like this (where andDist is an angle) rx x ry (y Math.cos(angDist)) (z Math.sin(angDist)) rz (y Math.sin(angDist)) (z Math.cos(angDist)) But, I'm not sure how to get the angle that the face is inclined at. Any suggestions? Or, are those white screen artifacts due to something else I've overlooked? |
36 | Rotating the playing field. (MonoGame) My maths isn't as good as it should be, I need to pick up some reference books on Trig. Could someone give me an idea of the maths if I wanted to revolve many sprites around a central point? It's a 2D system in MonoGame. I'm going to try to describe the scenario, I can't think of anything quite like it to reference. Imagine a game screen, you are looking down on the world, with my character in the middle, my character sprite will never change, but if I turn left or right I want everything else to rotate around the central point. Of course every sprite will have to be moved, and also rotate to account for the spin. Can someone point me in the right direction? Thanks. |
36 | Get 3D quad rotation matrix from points I have 4 3D points which represent a even quad in space. (So 3 points are sufficient) I need to get all the individual transformations (translation, rotation, dimensions) so that I can build that quad in my CSS 3D engine. So the default normal vector for a quad is 0, 0, 1 . What I have so far 4 points p0, p1, p2, p3 normal normal cross(p1 p0, p2 p0) axis and angle axis cross( 0, 0, 1 , normal) angle arccos(dot( 0, 0, 1 , normal)) rotation matrix rotationMatrix matrix4.fromAxisAngle(axis, angle) width and height width sqrt((p2.x p1.x) 2, (p2.y p1.y) 2, (p2.z p1.z) 2) height sqrt((p1.x p0.x) 2, (p1.y p0.y) 2, (p1.z p0.z) 2) translation x (p0.x p1.x p2.x p3.x) 4 y (p0.y p1.y p2.y p3.y) 4 z (p0.z p1.z p2.z p3.z) 4 It almost works, but some rotations are wrong or more specifically one rotation axis is missing. This is logical because the rotation is only build from the normal. So how can I get the full rotation? Here you see that the top and bottom quads are just rotated around the x axis but the y axis rotation is missing |
36 | How to map absolute Joystick position to object rotation? In my (Ogre) 3d scene I have an object that should be rotated locally based on Joystick input. I have a Joystick with min max values of 32767, 32767 on both X and Y axes. When the Joystick is in its origin position, the object should not be rotated. When the user moves the Joystick, the object in the 3d scene should follow this movement (or better orientation) up to a max. of 45 degrees on both axes. Or in other words when the user moves the Joystick e.g. fully to the left, the object's orientation in the 3d scene should be set to 45 degrees on the according axis. Being new to 3d programming I searched on the Internet on how to achieve this. I think to understand that I want to use Quaternions for this task. I found some examples and tutorials on how to use Quaternions for rotating objects. What I don't understand though is how I can map from the Joystick's current absolute axes positions to the absolute, local rotation of an object. I see that I could use the rotate() method of the object's node to set its rotation, but I understand that this rotates the object relatively to it's current position. But instead I want to map from the Joystick's absolute position to the absolute orientation rotation of the object in the scene. Any advice how I should approach this? |
36 | Calculate quaternion rotations between two values I have a quaternion Q1 X 0.023995593190193176 Y 0.4076451063156128 Z 0.04357096180319786 W 0.9117847681045532 and I have a keyframe value Q2 which is based on Q1 X 0.176469 Y 0.368251 Z 0.479782 W 0.776569 Now my question is how can I get the correct keyframe values if there would be no extra start values ? I mean if Q1 is 1,0,0,0 (w,x,y,z). (no extra start values) So basically I need to rotate my object to the same pose but from the default values (1,0,0,0) start not from Q1. |
36 | How do I rotate shoulder bone up and down using Rotate and Space.World independend on model orientation I wanted to move my character's arms up and down in a straight way. The Rotation Gizmo tool can do exactely that. Playing with the wheel of the Rotation Gizmo tool in the attached screenshot (marked with red arrows in my screenshot), I could move the arms down in a straight way I can do the same using the following script using System.Collections using System.Collections.Generic using UnityEngine public class MyPlayer MonoBehaviour public Transform Shoulder private Quaternion Rotation private float f 0f private void OnGUI() if (GUI.Button(new Rect(0, 70, 50, 30), quot quot )) f 1 Shoulder.Rotate( f, 0, 0, Space.World) This works perfectly fine, but no longer when I rotate the main model ( the parent of the shoulder). How could I make this script independend on the main transform's orientation? Thank you! Edit I would guess that I have to take the main transform ( parent) orientation into account in order to subtract its global rotation from the calculations, but not really knowing which values I should choose, I didn't find the correct formula. However, FYI, I tried the following using System.Collections using System.Collections.Generic using UnityEngine public class MyPlayer MonoBehaviour public Transform Shoulder public Transform Mother private float f 0f private void OnGUI() if (GUI.Button(new Rect(0, 70, 50, 30), quot quot )) f 1 f Mother.transform.rotation.eulerAngles.x Shoulder.Rotate( f, 0, 0, Space.World) |
36 | What is an efficient way to get a look at direction from either a quaternion or a transformation matrix? So, I have an object in my custom engine (C ), with a column major transform in world space. I'm using a package that takes a look at direction as an input. What's the most efficient way to get a look at direction from this transform? Do I extract the rotation matrix? Do I try to extract a quaternion? |
36 | how to properly rotate in directX11 I am trying to Rotate a textured quad in directX however I think i am missing something. I am pretty sure it is because i am applying transformations to the WorldMatrix instead of the ObjectWorld, however i do not have an object world matrix so i am unsure how i would get that since i am not storing much except the texture and the position of 4 vertices directly to the buffer and only updated when it is needed. here is what i have tried bool GraphicsClass Render(float deltatime) D3DXMATRIX worldMatrix, viewMatrix, projectionMatrix, orthoMatrix, rotationZ bool result Clear the buffers to begin the scene. m D3D gt BeginScene(0.0f, 0.0f, 0.0f, 0.0f) Generate the view matrix based on the camera's position. m Camera gt Render() DrawingStuff Get the world, view, projection, and ortho matrices from the camera and d3d objects. m Camera gt GetViewMatrix(viewMatrix) m D3D gt GetWorldMatrix(worldMatrix) m D3D gt GetProjectionMatrix(projectionMatrix) m D3D gt GetOrthoMatrix(orthoMatrix) Transform World Matrix with a rotation matrix D3DXMatrixRotationZ( amp rotationZ, 90.0f) D3DXMatrixMultiply( amp worldMatrix, amp worldMatrix, amp rotationZ) Turn off the Z buffer to begin all 2D rendering. m D3D gt TurnZBufferOff() Put the bitmap vertex and index buffers on the graphics pipeline to prepare them for drawing. result m Bitmap gt Render(m D3D gt GetDeviceContext(), 124, 124) if(!result) return false Render the bitmap with the texture shader. result m TextureShader gt Render(m D3D gt GetDeviceContext(), m Bitmap gt GetIndexCount(), worldMatrix, viewMatrix, orthoMatrix, m Bitmap gt GetTexture()) if(!result) return false Turn the Z buffer back on now that all 2D rendering has completed. m D3D gt TurnZBufferOn() Present the rendered scene to the screen. m D3D gt EndScene() return true the full code can actually be downloaded from http www.rastertek.com dx11tut05.html with the minor difference that render takes in delta time since last frame using a custom timer class which is not provided by them as well as a few minor tweaks but it is mostly the same. i did find this http www.rastertek.com dx11tut25.html which i may try to implement however that is not really what i want, i want to rotate the actual quad, not the texture. |
36 | Euler adjustments between two quaternions I have two quaternions, q1 and q2. If my object's current rotation is at q1, but I need to get it to q2, what would be the process to figure out how much rotation I apply to x, y, and z in order to get there? In this example, x right, y up, z forward I've tried getting the delta between the two quaternions and unwrapping that into Eulers and moving the x, y, z the amount of the unwraped Vector3f, but that does not seem to give the correct values. Current implementation in pseudo code var dQuat Quaternion.Inverse(prevRotation) target.rotation dChange dQuat.eulerAngles This approach gives me only positive changes. If I rotate forward on x, I get positive lower numbers and if I rotate backwards on x, I get larger positive numbers. I'm looking for, in order to get to q2 from q1, rotate n degrees along your x, y, z... Thanks in advance for any help! |
36 | Programmatically determine UVs by rotating a plane along X axis I'm having a math brainfart while trying to solve what might be a simple problem. I've got a plane in 3d space (it's actually the face of a 10 sided die) Coordinates x,y,z Point top 0,0,1 Point left Sin (2pie9 10), Cos(2pie9 10), 0.1 .5878,.809,.1 Point right Sin (2pie 10) , Cos(2pie 10), 0.1 .5878,.809,.1 Point bot 1,0, 0.1 If you project that out, it's a plane with the top leaning back away from you, and the bottom closer to you. I'm trying to automatically build a UV map of that face to put a texture on, so think I should rotate it around the x asix so that it's only in 2D, then scale that to best fill up a 256x256 texture. I'm doing this in Three.JS for a canvas app. Is this the right approach? In this example http wecreategames.com games DiceBoard ( die creation code is in http wecreategames.com games DiceBoard die10.js ), I'm estimating the UVs by Build UVs scope.faceUvs scope.faceVertexUvs for (var f 0 f lt numHalfFaces f ) var faceuv new THREE.UV(.2, .6), new THREE.UV(.5, .75), new THREE.UV(.8, .6), new THREE.UV(.5, .2) scope.faceUvs 0 .push(new THREE.UV(0, 1)) scope.faceVertexUvs 0 .push(faceuv) But when I view on an iPhone or Android, it shows weird screen artifacts... I'm thinking because the UVs aren't exact. I think I'd apply some function like this (where andDist is an angle) rx x ry (y Math.cos(angDist)) (z Math.sin(angDist)) rz (y Math.sin(angDist)) (z Math.cos(angDist)) But, I'm not sure how to get the angle that the face is inclined at. Any suggestions? Or, are those white screen artifacts due to something else I've overlooked? |
36 | Rotate around an axis function for euler angles representation For a 3d game i need a function to rotate an euler representation around an arbitary axis by an angle. For example an object is rotated with euler angles (0,90,0). Now the object should be rotated by 100 degrees around the axis (0,1,0). The resulting angle will be (0,190,0) using rotation order YXZ. In this case I can add the angle to the euler value of the axis, however for an arbitary axis this will not work. Problem with Quaternions amp Rotation matrices With these representations the resulting rotations will always be smaller that 180 for each axis. I need the rotation to be lerped afterwards for example from (0,0,0) to (0,720,0). Basically I am searching for a way to display euler angles like most of the 3D editors. When you rotate an object around any arbitary axis rotation might be larger than 360 in the editor, like (420,720,15). |
36 | How can I modify the UV co ordinates on a texture so they converge to a point? I'm building a roof visualiser app, where someone can take a picture of their roof, define its outline, then visualise a new roof texture on it. I'm generating a 3D plane that matches the roof outline points, but I'd like the 3D planes material's UV's to match the perspective of the existing roof (i.e the lines converge into the distance as they move away from the user. Is this possible? The alternative solution is to figure out how to rotate the generated 3D plane to match the roof outline points, while matching the perspective too, but I'm thinking this may be more complicated. Step 1 Define roof oultine with points Step 2 Texture 3D plane with UV's mapped to maintain roof perspective based on slant defined in the 4 points Any tips on how to solve this? |
36 | Find out which way to rotate based on current rotation and final rotation I have one object that I want to rotate to a certain angle with 'smooth' rotation. I looked up on how to solve that and I came up with this enter image description here But how do I know in what way to rotate, positive or negative? According the the picture on ex. 1, I need to rotate positively because it is the closest way for me to rotate. And on the second it is the negative way. But how do I know this? I've tried several solutions but I can't seem to find anything that is correct. |
36 | Arcball Problems with UDK I'm trying to re create an arcball example from a Nehe, where an object can be rotated in a more realistic way while floating in the air (in my game the object is attached to the player at a distance like for example the Physics Gun) however I'm having trouble getting this to work with UDK. I have created an LGArcBall which follows the example from Nehe and I've compared outputs from this with the example code. I think where my problem lies is what I do to the Quaternion that is returned from the LGArcBall. Currently I am taking the returned Quaternion converting it to a rotation matrix. Getting the product of the last rotation (set when the object is first clicked) and then returning that into a Rotator and setting that to the objects rotation. If you could point me in the right direction that would be great, my code can be found below. class LGArcBall extends Object var Quat StartRotation var Vector StartVector var float AdjustWidth, AdjustHeight, Epsilon function SetBounds(float NewWidth, float NewHeight) AdjustWidth 1.0f ((NewWidth 1.0f) 0.5f) AdjustHeight 1.0f ((NewHeight 1.0f) 0.5f) function StartDrag(Vector2D startPoint, Quat rotation) StartVector MapToSphere(startPoint) function Quat Update(Vector2D currentPoint) local Vector currentVector, perp local Quat newRot Map the new point to the sphere currentVector MapToSphere(currentPoint) Compute the vector perpendicular to the start and current perp startVector cross currentVector Make sure our length is larger than Epsilon if (VSize(perp) gt Epsilon) Return the perpendicular vector as the transform newRot.X perp.X newRot.Y perp.Y newRot.Z perp.Z In the quaternion values, w is cosine (theta 2), where theta is the rotation angle newRot.W startVector dot currentVector else The two vectors coincide, so return an identity transform newRot.X 0.0f newRot.Y 0.0f newRot.Z 0.0f newRot.W 0.0f return newRot function Vector MapToSphere(Vector2D point) local float x, y, length, norm local Vector result Transform the mouse coords to 1..1 and inverse the Y coord x (point.X AdjustWidth) 1.0f y 1.0f (point.Y AdjustHeight) length (x x) (y y) If the point is mapped outside of the sphere ( length gt radius squared) if (length gt 1.0f) norm 1.0f Sqrt(length) Return the "normalized" vector, a point on the sphere result.X x norm result.Y y norm result.Z 0.0f else It's inside of the sphere Return a vector to the point mapped inside the sphere sqrt(radius squared length) result.X x result.Y y result.Z Sqrt(1.0f length) return result DefaultProperties Epsilon 0.000001f I'm then attempting to rotate that object when the mouse is dragged, with the following update code in my PlayerController. Get Mouse Position MousePosition.X LGMouseInterfacePlayerInput(PlayerInput).MousePosition.X MousePosition.Y LGMouseInterfacePlayerInput(PlayerInput).MousePosition.Y newQuat ArcBall.Update(MousePosition) rotMatrix MakeRotationMatrix(QuatToRotator(newQuat)) rotMatrix rotMatrix LastRot LGMoveableActor(movingPawn.CurrentUseableObject).SetPhysics(EPhysics.PHYS Rotating) LGMoveableActor(movingPawn.CurrentUseableObject).SetRotation(MatrixGetRotator(rotMatrix)) |
36 | How do I get a relative rotation between two positions? For example, I have two objects a amp b. a's position is 12, 16, 2 and b's position is 14, 16, 3 I need to know how to find a relative rotation between them. By relative rotation I mean this a's pitch and yaw so a is looking at b. I have no helping methods like lookingAt() etc. I only know a's x,y,z,yaw,pitch and b's x,y,z. Any help? |
36 | Rotate an object around a point in Ogre3D Possible Duplicate How can I rotate about an arbitrary point in 3D (instead of the origin)? I am new to 3D programming and I have been using Ogre3D lately to get a grasp of it. What I am trying to do is the following I want to make an entity rotate around a point (probably the parent SceneNode) in a circular way only in the X and Z axis. I have tried using yaw pitch roll and rotate but no luck, and I can't find any good tutorials how tos online. |
36 | THREE.JS why is the rotation only applied on the last axis used? my function function rotateAroundWorldAxis2(object, radians1, radians2) object.rotWorldMatrix.makeRotationX(radians1).makeRotationZ(radians2) object.rotWorldMatrix old code for Three.JS pre r54 rotWorldMatrix.multiply(object.matrix) new code for Three.JS r55 object.rotWorldMatrix.multiply(object.matrix) pre multiply object.matrix.copy( object.rotWorldMatrix ) old code for Three.js pre r49 object.rotation.getRotationFromMatrix(object.matrix, object.scale) old code for Three.js pre r59 object.rotation.setEulerFromRotationMatrix(object.matrix) code for r59 object.rotation.setFromRotationMatrix(object.matrix) my object was initialized like this object.rotWorldMatrix new THREE.Matrix4() |
36 | Projectile Rotation During Flight (Tank Game) I have a tank firing projectiles into the air. I want the projectiles to be rotated relative to their position along their flight path. See the diagram I drew in the image below. At any given point I know the x and y of the projectile, z represents initial velocity, theta is also known. |
36 | from normal to rotation matrix (i'm on OPENGL) i have a mesh O (object) and a mesh T (terrain). i know a single triangle in T and i want to orient O to be aligned to that triangle (torate O to align to T in that point). i have only the normal in the triangle. how can i achive the roation matrix? i have thought this algorithm pseudocode float normal2rotation(Vector3D normal) angleX Vector3D.angleBetween(normal, Vecto3D.Axis3D.X) angleY Vector3D.angleBetween(normal, Vecto3D.Axis3D.Y) angleZ Vector3D.angleBetween(normal, Vecto3D.Axis3D.Z) float result angleX, angleY, angleZ return result but it does not give me the desired result. |
36 | Convert quaternion to a different coordinate system OSVR has a right handed system x is right, y is up, z is near. I need to convert orientation data from a sensor in OSVR to a different right handed system in which x is forward, y is left, and z is up. I need to calculate the transformation that will convert a quaternion from one system to the other. I naively tried void osvrPoseCallback(const geometry msgs PoseStampedConstPtr amp msg) osvr to ros geometry msgs PoseStamped outputMsg outputMsg.header msg gt header outputMsg.pose.orientation.x msg gt pose.orientation.y outputMsg.pose.orientation.y msg gt pose.orientation.z outputMsg.pose.orientation.z msg gt pose.orientation.x outputMsg.pose.orientation.w msg gt pose.orientation.w osvrPosePub.publish(outputMsg) ros spinOnce() But that made things really weird. Facing north pitch is pitch, facing west, pitch is yaw, facing south, pitch is negative pitch... How can I convert my OSVR quaternion to the a corresponding quaternion in the new coordinate system? |
36 | Rotating and pitching a turret I am new to game development and I was trying to build a turret model, and control it through lua script in shiva3d. I can rotate it around the y axis which is no problem, but when it comes to pitching, I am not sure how to do that in a way which is independent of the Y rotation, for example, in the default position, rotating with a positive value around X aims upwards, which is what I expect. when I rotate it by 180 degrees around Y, the positive rotation around X aims downwards towards the ground instead of upwards. on the other hand, if I rotate by 90 degrees, the turret rotates around it self as if its rolling... I am not sure what to look for in order to understand how rotation in a 3d world should happen, so any pointers on that would be much appreciated |
37 | What are the app file size limitations for different smartphone OSes carriers? I know the iPhone App Store limits how large an app can be in general and there are also limitations with AT amp T over the size it can be to transmit over a data plan vs WiFi. I have no idea what, if any, these limits are for Android apps and what I'm finding online is a mix of different numbers. Does anyone know these numbers definitively? The Android game I'm porting is in the 20 30MB range and we'd like to know if we need to further reduce its size. |
37 | How to port a game from IPad to Iphone I just finished developing a 2D side scroll game for the IPad using Cocos2d and Box2d. Now we want to make an IPhone 4 version of the game, but I'm still not sure what is the best way to do it. I was thinking to just create a new target on my project, remove all the current resources from the Build Phases and create a new Resources folder with all the assets of the game scaled to the new resolution. Of course this approach would take a lot of work, specially from the designer, since there are a lot of images on the game, 30 levels with 3 layers of parallax, and over 100 animations between all the elements, plus the SVG levels that map physics world (we are using level SVG parser). I would also have to check all the touch functions and the sprites with a hard coded position (mostly Hud and the Menu). I did tried to use the win Size for this, but I'm pretty sure there are sprites with fixed positions. I know that checking the Menu and Hud position should not take much time, but I'm worried about the time it could take to scale all the images, and specially the SVG files that map the physics of the game. I would like to know if I'm in the right path regarding the porting of the game or if there if someone have though of a better easy solution. I tried modifying the gluLookAt eye z parameter, but this didn't work really well. I haven't work with OpenGL since college around 3 years ago, and I don't remember very well the math behind the low level pipeline of it. Anyway, I don't think that modifying the Cocos2d rendering steps could work for my problem. |
37 | Efficient Bullet Firing Class I've been struggling with this for a while. I have been trying to create a bullet pool class for a game I have made that doesn't cause a significant fps drop. I have tried creating a bullet pool and have also tried dynamically creating and deleting bullets, both of which drop the fps of the game around 10 15. I ran a test a few days ago and just put a return statement in the bullet pool's firebullet function, which represented the logic leading up to this, function calling, etc. This only dropped the fps 2 4. If I can fire bullets without dropping the fps more than another 2 3, I would be satisfied. My bullets are autorelease objects that are a subclass of a ccnode. I create a ccsprite and a box2d b2body for each one. I am working on the ios platform. Any thoughts on how to make this more efficient? Has anyone managed to do something similar to this? |
37 | Sound Delay With AVAudio Player I'm using the following code in my viewDidLoad to load a sound NSURL url NSURL fileURLWithPath NSString stringWithFormat " Moto Hit Sound.mp3", NSBundle mainBundle resourcePath NSError error hitSoundPlayer AVAudioPlayer alloc initWithContentsOfURL url error amp error hitSoundPlayer.numberOfLoops 0 Then I'm using this in a void method to play the sound if(CGRectIntersectsRect(main.frame, enemy1.frame)) hitSoundPlayer play This does seem to work, however the first time the sound is played there is a lot of lag and the game stops temporarily. I'm using this same method for when in an IBAction and it works fine, it must be the fact that it's also detecting a collision that makes the sound lag. If I want to be able to play sounds quickly and on the spot without any sort of lag am I doing the right thing? Do I want to use another method? I'm not using any frameworks like cocos2d. If you need to see any more code just ask. |
37 | Network client server message exchange and clock synchronization help i'm doing a fast paced physics game that is a table hockey. With two mallets and one puck. The game runs on iphone ipad and i'm doing the multiplayer part through GameCenter. This is how the network system works. The client wich stars the match, will be settled as the server and the one that accepts the match request is the client. The 'server' has the physics running and the response is immediate and the client also has their physics running so it looks smooth between messages exchange. What i do as the server, is that i send to the client my puck velocity and my position and the client adjusts his puck velocity position related to the server to keep it sync. Otherwise the physics desynchronizes and it screws it up. When the network latency is good, bellow 100ms the results are pretty good, i got a smooth playable game on the client side and the weird behavior are minimum. The problem happens when the lag is around 150 to 200ms. In that case, happens that my client puck already hitted a edge and inverted direction but it receives a delay message from the server and it backs a bit causing a weird feeling to the ball behavior. I've readed a few things about it Pong Network Example Click Synchronization Example Wikipedia on Clock Sync So, how can i solve this? As far as i've read the best option that i have is to do a clock synchronization on the server client with a timestamp so that when i get delay messages related to my clock, i just ignore then and let the clients simulation do the job. Do you guys agree with that? And since im sending data unreliable (UDP) i may get delayed messages or messages out of order. If that is the best approach, how do i implement the clock synchronization. I've read the steps on how to but i didn't quite understand it. It says that Client stamps current local time on a "time request" packet and sends to server. Upon receipt by server, server stamps server time and returns Upon receipt by client, client subtracts current time from sent time and divides by two to compute latency. It subtracts current time from server time to determine client server time delta and adds in the half latency to get the correct clock delta. (So far this algothim is very similar to SNTP) The client repeats steps 1 through 3 five or more times, pausing a few seconds each time. Other traffic may be allowed in the interim, but should be minimized for best results The results of the packet receipts are accumulated and sorted in lowest latency to highest latency order. The median latency is determined by picking the mid point sample from this ordered list. All samples above approximately 1 standard deviation from the median are discarded and the remaining samples are averaged using an arithmetic mean. Following this example i would have this Lets pretend the game has loaded and my client time is 0 now, so i send to the server that my time is 0. The messages takes 150ms to get to the server but the server's clock had already started and is 1 second ahead of the client. When the server get the message the time will be 1.15 and sends that time to client, are we good? Lets pretend our lag is constant at 150ms. Now the client receives the time 1.15 and subtracts current time from sent time and divides by two to compute latency. Wich is 0.3 0 0.3 2 150ms. It subtracts current time from server time to determine client server time delta and adds in the half latency to get the correct clock delta Client time 0.3 Server time 1.15 0.3 1.15 .85 latency(.15) 1 How is that synchronized? What am i missing? It's my first time on multiplayer and network experience, so i'm a bit confused. Thank you. |
37 | Best way to learn iphone game development? I know php and some python, but not much c. Where should I start to learn iphone game development? Is there some recommended books tutorials for beginners? I'm looking at using cocos2d but I'm open to anything that isn't too limited. |
37 | How to load a text file from a server into iPhone game with AS3 in Adobe AIR? Im creating an iPhone game with Adobe AIR, and I want to be able to load a simple text msg into an dynamic text box on the games front screen from my server (and then be able to update that text file on the server, so it updates automatically in the game after the game is on the app store) How would I go about acheiving that? is it as simple as using a getURL? are there any specifical issues with trying to do this on the iPhone via AIR that I should be aware of? Thanks for any advice. |
37 | What are the minimum requirements for UDK on iOS? Infinity Blade asks for 3GS or better devices, which I'm told is because it uses OpenGL ES 2. Will every game made with the iOS version of the UDK only work with 3GS devices and up? |
37 | Cocos2d pause game freezes the screen I am trying to create pause screen for my game. The game is developed upon continuous scrolling background (top to bottom) with obstacles which are moving independently (left to right). Below is the code PauseScene.h interface PauseScene CCNode property (nonatomic, retain) HelloWorldScene mainScene (PauseScene )scene (id) init end PauseScene.m implementation PauseScene (id) init if (self super init ) Adding RESUME and QUIT button and few others to make the whole Pause screen return self Called the method when Resume button is selected (void) Resume (id) sender CCDirector sharedDirector startAnimation CCDirector sharedDirector resume self.mainScene.userInteractionEnabled YES self.mainScene removeChild self self.mainScene StartGame StartGame in MainScene contains the same code which commented out above, I will paste StartGame method later Quit method is called when the Quit button is pressed (void) Quit (id) sender CCDirector sharedDirector resume CCDirector sharedDirector startAnimation self.mainScene.userInteractionEnabled YES self.mainScene removeChild self NSLog( "Pre Reload", nil) self.mainScene scheduleOnce selector(ReloadGame) delay 1.0f self.mainScene ReloadGame Reload method contains the code commented above end PauseScene is mere node class. StartGame and ReloadGame methods in MainScene file (void) StartGame Create and display HUD layer, like, scores, navigation buttons, etc. Resuming the game CCDirector sharedDirector stopAnimation CCDirector sharedDirector resume CCDirector sharedDirector startAnimation (void) ReloadGame Resume the game CCDirector sharedDirector stopAnimation CCDirector sharedDirector resume CCDirector sharedDirector startAnimation CCDirector sharedDirector replaceScene HelloWorldScene scene withTransition CCTransition transitionFadeWithDuration 1.0f The pause button is displayed in HUD layer of MainScene, so, when the pause button is clicked, we will pause the game and display the PauseScene (void)onPauseClicked (id)sender Code to display the pause node of this scene Pause the game CCDirector sharedDirector stopAnimation CCDirector sharedDirector pause When I comment out that stopAnimation and pause part the Pause and Resume works perfect. But when I implement any of these, at the time of quitGame, replaceScene is not working somehow. I think this is because game goes in pause mode but it is not working even if I call replaceScene using scheduler on delay of 5 10 seconds. And if I don't use these stopAnimation and pause, some sprites which are given CCAction are not being paused and goes on even when my game is paused. Your help is appreciated because I am using Cocos2d 3.0 and unable to find any proper help. |
37 | Using tilemaps for an isometric football game with cocos2dx I am writing a simple soccer game in cocos2d x and recently found out that older iOS versions do not support cocos2d sprites larger than 1024x1024px. I was thinking about using isometric tilemaps to create a larger football field. Is this the way to go ? If so, how can i convert a convert my 2048x2048px football field image into several isometric tiles ? |
37 | Help implementing virtual d pad Short Version I am trying to move a player around on a tilemap, keeping it centered on its tile, while smoothly controlling it with SneakyInput virtual Joystick. My movement is jumpy and hard to control. What's a good way to implement this? Long Version I'm trying to get a tilemap based RPG "layer" working on top of cocos2d iphone. I'm using SneakyInput as the input right now, but I've run into a bit of a snag. Initially, I followed Steffen Itterheim's book and Ray Wenderlich's tutorial, and I got jumpy movement working. My player now moves from tile to tile, without any animation whatsoever. So, I took it a step further. I changed my player.position to a CCMoveTo action. Combined with CCfollow, my player moves pretty smoothly. Here's the problem, though Between each CCMoveTo, the movement stops, so there's a bit of a jumpiness introduced between movements. To deal with that, I changed my CCmoveTo into a CCMoveBy, and instead of running it once, I decided to have it CCRepeatForever. My plan was to stop the repeating action whenever the player changed directions or released the d pad. However, when the movement stops, the player is not necessarily centered along the tiles, as it should be. To correctly position the player, I use a CCMoveTo and get the closest position that would put the player back into the proper position. This reintroduces an earlier problem of jumpiness between actions. What is the correct way to implement a smooth joystick while smoothly animating the player and keeping it on the "grid" of tiles? Edit It turns out that this was caused by a "Bug Fix" in the cocos2d engine. |
37 | CATiledLayer drawing delay I am developing an iphone app. It has following page structure, 1.List of game levels in a UITableView 2.Game page I use "UIViewAnimationTransitionFlipFromRight" between pages Game page has 3 views, One is a scrollView in that my game grid is drawn. Game grid is a sub class of UIView ,that added to Scrollview. To support zooming i use CATiledLayer to draw the grid(20 20). MY problem is GameGrid shows white or last played puzzles grid contents for a few seconds and then refresh(flashing) to the new content. My GameGrid class as follows implementation GameGrid (Class)layerClass return CATiledLayer class (id)initWithFrame (CGRect)frame if ((self super initWithFrame frame )) CATiledLayer tempTiledLayer (CATiledLayer )self.layer tempTiledLayer.levelsOfDetail 5 tempTiledLayer.levelsOfDetailBias 2 self.opaque YES return self (void)drawRect (CGRect)r empty (void)drawLayer (CALayer )layer inContext (CGContextRef)context here i am drawing grid filling rect lines string etc.. |
37 | Corona SDK Animation takes a long time to play after "prepare" step First off, I'm using the current publicly available build, version 2011.704 I'm building a platformer, and have a character that runs along and jumps when the screen is tapped. While jumping, the animation code has him assume a svelte jumping pose, and upon the detection of a collision with the ground, he returns to running. All of this happens. The problem is that there is this strange gap of time, about 1 2 a second by the feel of it, where my character sits on the first frame of the run animation after landing, before it actually starts playing. This leads me to believe that the problem is somewhere between the "prepare" step of loading up a sprite set's animation sequence and the "play" step. Thanks in advance for any help ). My code for when my character lands is as follows local function collisionHandler ( event ) if (event.object1.myName "character") and (event.object2.type "terrain") then inAir false characterInstance prepare( "run" ) TODO time between prepare and play is curiously long... characterInstance play() end end |
37 | Can I do iPhone game dev on iPod touch? I do not want a mobile phone, but are there any issues I'd run into by developing games on an iPod for iPhone? |
37 | Graphic Animation tools and workflow for iPhone iOS game development I've got some experience producing Flash games, and for all Flash's faults I find the designer developer workflow pretty decent. I can set up a template FLA with placeholder movieclips and code to that independently of a designer animator doing their thing. When it comes time for integration, I can either compile their animations into my project by using a SWC or by loading SWF's at runtime. I've had a quick look, but I can't see any tools that offer a similar workflow for iOS game development. Could anyone producing iOS games shed any light on how they're handling designer animator developer workflow? |
37 | How do you save and load settings for an iOS game? I've read a few beginning iPhone game programming books, and they've helped tremendously in my education and advancement in creating a few simple games, but of all the books I've read, there doesn't seem to be anything about creating a Settings Menu or how to change and save settings within a game. What are some ways that settings can be saved loaded? Where are these settings saved? This may seem like a simple, uninteresting question, but I can't find anywhere that has a good explanation on how to go about creating a settings menu and how the data is saved loaded each time the program ends starts... Mind you I'm not really expecting to have code thrown at me, but an explanation on how the structure works and how to wrap my head around the whole concept (though code is pretty )). Or even some articles that explain the concept that I could read would be very helpful. |
37 | Comparison between Cocos2d and Corona I'm having a really hard time deciding which way to go on this. I'm about to start developing a game and I haven't been able to find many good comparisons between these approaches. I don't have many requirements for the game yet, but here is what I do know. needs to work on iPhone I don't have much money ( 400 for Unity for iPhone is probably too much. I can probably afford 99 for Corona.) Graphics will be 2D Physics support is not needed Ability to use particles would be nice Game Center support would be nice (Corona is planning to support it soon) It would be nice to be able to support Android as well if it isn't much effort. I have done my own research, so I know basic things about them. I know Corona uses Lua and Cocos2D uses Objective C. I know that Corona allows deployment to iPhone and Android, but how easy is it? Cocos2D is free, but so many people talk about how easy it is to use Corona, but I don't like being restricted to features Corona supports or the price tag. I feel so torn here. |
37 | cocos3d versus Unity for simple IOS 3D games? Wondering if anyone here happens to have experience in doing some simple 3D based games apps for IOS, using cocos3d amp Unity and could give some pointers....questions I have are GENERAL 1) It seems currently cocos3d has the most traction in terms of a free 3D games engine for IOS development? 2) If one wanted to step up from the free IOS games engine, to a commercial one it would seem Unity is a popular choice, however you would then not really be doing apple objective c development, but rather unity development and pushing a button to pop out an IOS deployable artifact correct? FOR MY SPECIFIC REQUIREMENT If I was interested in doing the following develop a relatively simple 3D application for iPhone iPad have a small 'world' such as a room with a few basic items in it (table, cupboard) ability to 'drop' a basket ball in the room and have it bounce around based on a physics engine amp perhaps some user input (not sure what, lets say control wind direction) monitor it and react accordingly e.g. say if it goes into a net which is in the room then add a point to the scoreboard At a high level how would one do this using Unity versus using cocos3d, for example 3) Which would be quicker to develop such a basic iPhone iPad game simulation out of Unity cocos3d? 4) Would 'building your world room' approach be different? Like in Unity would you build tables cupboards within a Unity IDE which would make it very quick, whereas with cocos3d would you have to do this programmatically? 5) Would the programming aspect of letting the ball go and monitoring it be different between the two? Or would you roughly in both cases just be setting up world, release ball in certain position, and then engaging physics engine? 6) Any advice guidance re which tool approach to use? (Unity versus cocos3d) 7) Re using cocos3d for my requirement, what additional tools would you recommend above beyond XCode? (e.g. just perhaps some sort of 3D design tool to help model the room and import save somehow for us in cocos3d) Basically I'm a hobbyist iOS developer who wants to do some 3d, so the concept of using a free open source approach such as cocos3d sounds great as (a) it's free, (b) keep using existing skill set re objective c etc, BUT the biggest unknown to me is whether by chosing cocos3d would I be giving myself say 20 hours of work to develop a 3d app animation that could be developed in 1 hour in one of these commercial product (e.g. Unity)? |
37 | Is it true that to test a game on the iPhone or iPad, we either need to pay 99 to join Apple Developer program, or jailbreak the iPad? To test a program for iPhone or iPad, seems like the only way is to join the Apple Developer program and pay 99 per year? Can you also jailbreak the iPhone or iPad and be able to test it? |
37 | How to balance audio levels to be loud enough yet safe There are a few sound effects in my game that sound a bit piercing over earbuds but OK when played through the iPhone speaker. Also sound levels seem lower on older hardware. Is there some objective way to be sure my sounds are loud enough yet safe? Notes I made my music with GarageBand for iPad. The output was very hot but not clipped. To preview the sounds on my computer I played them in the iPad simulator and matched the volume coming out of my iPhone. To resolve my volume issues, I reduced the high end in Amadeus Pro using the EQ tool. A couple passes for each of the worst sound clips let me reduce the shrillness without muting the volume too badly. Thanks everyone for your help. |
37 | Meshes crashed memory from CharacterCustomization example I am trying the CharacterCustomization example from Unity3D which contains two scenes Dressing room and VirtualWorld, run the VirtualWorld on iPhone, it could run but at last it will crashed, Instruments and profiler, I found the meshes are always increased and run out of memory. Anybody could help? thanks.Environment Unity 3.4.0, Xcode 4.0.2, iOS SDK 4.3 |
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