data2/text/DLP/1027878.txt

Ticket Name: TDA2HG: [Opengl] -- the cube usage in fbo

Query Text:
Part Number: TDA2HG Other Parts Discussed in Thread: TDA2 hi: I have a question about the usage of cubemap in fbo; the simple code as bellow: { glGenFramebuffers(1, &fboID); glBindFramebuffer(GL_FRAMEBUFFER,fboID); glGenTextures(1, &cubemapID); glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapID); for (unsigned int i = 0; i < 6; ++i) { glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB, 256, 256, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr); } glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glUniform.. //update the uniform variable glViewport(0, 0, 256, 256); for (unsigned int i = 0; i < 6; ++i) { glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, cubemapID, 0); if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) { printf("glCheckFramebufferStatus error!\n"); } glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); renderCube(); } } when i test the code, it works well on windows, but when i move it to the tda2 platform, the question is comming, sometimes the effiect is black , or is white, or white and black , or other colors, it's change every time. how is this? and how to resolved it? thanks

Responses:
Hello, Can you try and see if this works:     // Setup texture for cubemap
    glGenTextures(1, &textureCubeMap);
    char buffer0[CUBEMAP_TEX_LEN * CUBEMAP_TEX_LEN * 6];

    glBindTexture(GL_TEXTURE_CUBE_MAP, textureCubeMap);
    memset((void *)buffer0, 0x50, CUBEMAP_TEX_LEN*CUBEMAP_TEX_LEN*6);
    for(GLuint i = 0; i < 6; i++)
    {
            glTexImage2D(
                            GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
                            0, GL_RGBA8, CUBEMAP_TEX_LEN, CUBEMAP_TEX_LEN,
                            0, GL_RGBA, GL_UNSIGNED_BYTE, (char *)buffer0
                        );
    }

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

    // Setup Framebuffer for cubemap
    glGenFramebuffers(1, &fbCubeMap);
    
    
    // Rendering part
    GLint current_fbo;
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &current_fbo);
    glBindFramebuffer(GL_FRAMEBUFFER, fbCubeMap);
    
    // Render to cubemap
    for (int i = 0; i < 6; i++)
	{
        glFramebufferTexture2D(GL_FRAMEBUFFER,
		    GL_COLOR_ATTACHMENT0,
		    GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
		    textureCubeMap,
		    0);
	    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
	    //.... draw/render to cube map surface
	}
	
	// Bind the original frame buffer
	glBindFramebuffer(GL_FRAMEBUFFER, current_fbo);
	
	// Use cubemap texture
	glBindTexture(GL_TEXTURE_CUBE_MAP, textureCubeMap);

    //... draw to the final framebuffer using cubemap
    // In the shader code, use samplerCube to sample texture
    // e.g:
    // uniform samplerCube skybox;
    // ...
    // vec4 colorval = texture(skybox, direction);
    

    
    
	    



    


 If it still doesn't work, can you try and use glGetError to check for any errors? Regards Hemant