Frame capture in Xcode fails

I am using Xcode 4.5.1 and testing on an iPhone5 with iOS6. I was using the frame capture function without problem, but suddenly it stopped working. When I press the frame capture button, it seems the frame is captured, and the phone switches to a blank screen, only to suddenly switch back to the application screen, and the application keeps running. I can still debug and pause the application, but there's no way to get the frame capture. I don't see any errors in the console either. The reason it stopped working is this piece of code. This code is supposed to render something to a rendertexture, but the rendertexture seems blank. I wanted to use the frame capture function to find out what's wrong, but the code itself won't let me capture... :( Any idea why? ``` // ------------- init function ----------------- // Create the framebuffer and bind it glGenFramebuffers(1, &g_framebuffer); glBindFramebuffer(GL_FRAMEBUFFER, g_framebuffer); //Create the destination texture, and attach it to the framebuffer’s color attachment point. glGenTextures(1, &g_texture); glBindTexture(GL_TEXTURE_2D, g_texture); 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, g_texture, 0); //Test the framebuffer for completeness GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER) ; if(status != GL_FRAMEBUFFER_COMPLETE) { NSLog(@"failed to make complete framebuffer object %x", status); } else { NSLog(@"SkyPlugin initialized"); } // ----------------- on update ------------------ glGetIntegerv(GL_FRAMEBUFFER_BINDING, &oldFBO); glGetIntegerv(GL_VIEWPORT, oldViewPort); // set the framebuffer and clear glBindTexture(GL_TEXTURE_2D, 0); glBindFramebuffer(GL_FRAMEBUFFER, g_framebuffer); glViewport(0, 0, 32, 32); //glClearColor(0.9f, 0.1f, 0.1f, 1.0f); glDisable(GL_DEPTH_TEST); glClear(GL_COLOR_BUFFER_BIT); // Set shader glUseProgram(m_program); // do some glEnableVertexAttribArray // ... // texture setting glActiveTexture(GL_TEXTURE0); glUniform1i(m_uniform, 0); ResourceManager* resourceManager = ResourceManager::GetInstance(); glBindTexture(GL_TEXTURE_2D, m_texture[0]); // ----------- Draw ----------- // Draws a full-screen quad to copy textures static const vertexDataUV quad[] = { {/*v:*/{-1.f,-1.f,0}, /*t:*/{0,0}}, {/*v:*/{-1.f,1,0}, /*t:*/{0,1}}, {/*v:*/{1,-1.f,0}, /*t:*/{1,0}}, {/*v:*/{1,1,0}, /*t:*/{1,1}} }; static const GLubyte indeces[] = {0,2,1,3}; glVertexAttribPointer(m_posAttrib, 3, GL_FLOAT, 0, sizeof(vertexDataUV), &quad[0].vertex); glVertexAttribPointer(m_texCoordAttrib, 2, GL_FLOAT, 0, sizeof(vertexDataUV), &quad[0].uv); glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_BYTE, indeces); // ------------ End // go back to the main framebuffer! glBindFramebuffer(GL_FRAMEBUFFER, oldFBO); glViewport(oldViewPort[0], oldViewPort[1], oldViewPort[2], oldViewPort[3]); glEnable(GL_DEPTH_TEST); //glClearColor(0.1f, 0.1f, 0.1f, 1.0f); ``` Edit: (2012/October/28) I found out why the above code was not working. I forgot to bind a render buffer! The code below works, but still the frame capture fails when this code is active... On init, // Create the renderbuffer and bind it glGenRenderbuffers(1, &g_renderbuffer); glBindRenderbuffer(GL_RENDERBUFFER, g_renderbuffer); glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8_OES, w, h); ``` // Create the framebuffer and bind it glGenFramebuffers(1, &g_framebuffer); glBindFramebuffer(GL_FRAMEBUFFER, g_framebuffer); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, g_renderbuffer); //Create the destination texture, and attach it to the framebuffer’s color attachment point. glGenTextures(1, &g_texture); glBindTexture(GL_TEXTURE_2D, g_texture); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); 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, g_texture, 0); ``` On update, ``` glGetIntegerv(GL_RENDERBUFFER_BINDING, &oldRBO); glGetIntegerv(GL_FRAMEBUFFER_BINDING, &oldFBO); glGetIntegerv(GL_VIEWPORT, oldViewPort); // set the framebuffer and clear glBindTexture(GL_TEXTURE_2D, 0); glBindFramebuffer(GL_FRAMEBUFFER, g_framebuffer); glBindRenderbuffer(GL_RENDERBUFFER, g_renderbuffer); glViewport(0, 0, 32, 32); // ... draw stuff ... ``` End of update, ``` // go back to the main framebuffer! glBindFramebuffer(GL_FRAMEBUFFER, oldFBO); glBindRenderbuffer(GL_RENDERBUFFER, oldRBO); ```