File size: 5,374 Bytes
8c93108
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
import numpy as np
import torch
import xatlas
import trimesh
import moderngl
from PIL import Image


def make_atlas(mesh, texture_resolution, texture_padding):
    atlas = xatlas.Atlas()
    atlas.add_mesh(mesh.vertices, mesh.faces)
    options = xatlas.PackOptions()
    options.resolution = texture_resolution
    options.padding = texture_padding
    options.bilinear = True
    atlas.generate(pack_options=options)
    vmapping, indices, uvs = atlas[0]
    return {
        "vmapping": vmapping,
        "indices": indices,
        "uvs": uvs,
    }


def rasterize_position_atlas(
    mesh, atlas_vmapping, atlas_indices, atlas_uvs, texture_resolution, texture_padding
):
    ctx = moderngl.create_context(standalone=True)
    basic_prog = ctx.program(
        vertex_shader="""
            #version 330
            in vec2 in_uv;
            in vec3 in_pos;
            out vec3 v_pos;
            void main() {
                v_pos = in_pos;
                gl_Position = vec4(in_uv * 2.0 - 1.0, 0.0, 1.0);
            }
        """,
        fragment_shader="""
            #version 330
            in vec3 v_pos;
            out vec4 o_col;
            void main() {
                o_col = vec4(v_pos, 1.0);
            }
        """,
    )
    gs_prog = ctx.program(
        vertex_shader="""
            #version 330
            in vec2 in_uv;
            in vec3 in_pos;
            out vec3 vg_pos;
            void main() {
                vg_pos = in_pos;
                gl_Position = vec4(in_uv * 2.0 - 1.0, 0.0, 1.0);
            }
        """,
        geometry_shader="""
            #version 330
            uniform float u_resolution;
            uniform float u_dilation;
            layout (triangles) in;
            layout (triangle_strip, max_vertices = 12) out;
            in vec3 vg_pos[];
            out vec3 vf_pos;
            void lineSegment(int aidx, int bidx) {
                vec2 a = gl_in[aidx].gl_Position.xy;
                vec2 b = gl_in[bidx].gl_Position.xy;
                vec3 aCol = vg_pos[aidx];
                vec3 bCol = vg_pos[bidx];

                vec2 dir = normalize((b - a) * u_resolution);
                vec2 offset = vec2(-dir.y, dir.x) * u_dilation / u_resolution;

                gl_Position = vec4(a + offset, 0.0, 1.0);
                vf_pos = aCol;
                EmitVertex();
                gl_Position = vec4(a - offset, 0.0, 1.0);
                vf_pos = aCol;
                EmitVertex();
                gl_Position = vec4(b + offset, 0.0, 1.0);
                vf_pos = bCol;
                EmitVertex();
                gl_Position = vec4(b - offset, 0.0, 1.0);
                vf_pos = bCol;
                EmitVertex();
            }
            void main() {
                lineSegment(0, 1);
                lineSegment(1, 2);
                lineSegment(2, 0);
                EndPrimitive();
            }
        """,
        fragment_shader="""
            #version 330
            in vec3 vf_pos;
            out vec4 o_col;
            void main() {
                o_col = vec4(vf_pos, 1.0);
            }
        """,
    )
    uvs = atlas_uvs.flatten().astype("f4")
    pos = mesh.vertices[atlas_vmapping].flatten().astype("f4")
    indices = atlas_indices.flatten().astype("i4")
    vbo_uvs = ctx.buffer(uvs)
    vbo_pos = ctx.buffer(pos)
    ibo = ctx.buffer(indices)
    vao_content = [
        vbo_uvs.bind("in_uv", layout="2f"),
        vbo_pos.bind("in_pos", layout="3f"),
    ]
    basic_vao = ctx.vertex_array(basic_prog, vao_content, ibo)
    gs_vao = ctx.vertex_array(gs_prog, vao_content, ibo)
    fbo = ctx.framebuffer(
        color_attachments=[
            ctx.texture((texture_resolution, texture_resolution), 4, dtype="f4")
        ]
    )
    fbo.use()
    fbo.clear(0.0, 0.0, 0.0, 0.0)
    gs_prog["u_resolution"].value = texture_resolution
    gs_prog["u_dilation"].value = texture_padding
    gs_vao.render()
    basic_vao.render()

    fbo_bytes = fbo.color_attachments[0].read()
    fbo_np = np.frombuffer(fbo_bytes, dtype="f4").reshape(
        texture_resolution, texture_resolution, 4
    )
    return fbo_np


def positions_to_colors(model, scene_code, positions_texture, texture_resolution):
    positions = torch.tensor(positions_texture.reshape(-1, 4)[:, :-1])
    with torch.no_grad():
        queried_grid = model.renderer.query_triplane(
            model.decoder,
            positions,
            scene_code,
        )
    rgb_f = queried_grid["color"].numpy().reshape(-1, 3)
    rgba_f = np.insert(rgb_f, 3, positions_texture.reshape(-1, 4)[:, -1], axis=1)
    rgba_f[rgba_f[:, -1] == 0.0] = [0, 0, 0, 0]
    return rgba_f.reshape(texture_resolution, texture_resolution, 4)


def bake_texture(mesh, model, scene_code, texture_resolution):
    texture_padding = round(max(2, texture_resolution / 256))
    atlas = make_atlas(mesh, texture_resolution, texture_padding)
    positions_texture = rasterize_position_atlas(
        mesh,
        atlas["vmapping"],
        atlas["indices"],
        atlas["uvs"],
        texture_resolution,
        texture_padding,
    )
    colors_texture = positions_to_colors(
        model, scene_code, positions_texture, texture_resolution
    )
    return {
        "vmapping": atlas["vmapping"],
        "indices": atlas["indices"],
        "uvs": atlas["uvs"],
        "colors": colors_texture,
    }