StackOverflow2013

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copied!<p>To render the scene to a texture you must use a framebuffer associated with a texture. Here is a method that i created to simplify it :</p> <pre><code>void glGenTextureFromFramebuffer(GLuint *t, GLuint *f, GLsizei w, GLsizei h) { glGenFramebuffers(1, f); glGenTextures(1, t); glBindFramebuffer(GL_FRAMEBUFFER, *f); glBindTexture(GL_TEXTURE_2D, *t); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, *t, 0); GLuint depthbuffer; glGenRenderbuffers(1, &depthbuffer); glBindRenderbuffer(GL_RENDERBUFFER, depthbuffer); glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, w, h); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthbuffer); GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER); if(status != GL_FRAMEBUFFER_COMPLETE) NSLog(@"Framebuffer status: %x", (int)status); } </code></pre> <p>You can create the frame buffer and the texture easily :</p> <pre><code>GLuint _texture, _framebuffer; GLsizei w,h; float scale = [UIScreen mainScreen].scale; w = self.view.bounds.size.width * scale; h = self.view.bounds.size.height * scale; glGenTextureFromFramebuffer(&_texture, &_framebuffer, w, h); </code></pre> <p>You can later use _framebuffer to render the scene into _texture in your draw method :</p> <pre><code>glBindFramebuffer(GL_FRAMEBUFFER, _framebuffer); //draw here the content you want in the texture //_texture is now a texture with the drawn content //bind the base framebuffer glBindFramebuffer(GL_FRAMEBUFFER, 0); //or if you use GLKit [view bindDrawable]; //draw normaly </code></pre> <p>Now you can do what you want with the texture. If you want to do some post processing (blur, bloom, shadow, etc...) you can !</p>

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