我在使用ios處理離屏渲染時遇到問題。以下是設置幀緩衝區對象和關聯緩衝區的代碼。它與蘋果在其開發者中心的代碼基本相同。ios上的framebuffer對象渲染
glGenFramebuffers(1, &pick_id);
glBindFramebuffer(GL_FRAMEBUFFER, pick_id);
GLuint color_id, depth_id;
glGenRenderbuffers(1, &color_id);
glBindRenderbuffer(GL_RENDERBUFFER, color_id);
glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA4, screen_width, screen_height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color_id);
glGenRenderbuffers(1, &depth_id);
glBindRenderbuffer(GL_RENDERBUFFER, depth_id);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, screen_width, screen_height);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_id);
std::cout << pick_id << " " << color_id << " " << depth_id << std::endl;
switch(glCheckFramebufferStatus(GL_FRAMEBUFFER))
{
case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT: std::cout << "framebuffer incomplete attachment" << std::endl; break;
case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT: std::cout << "framebuffer incomplete missing attachment" << std::endl; break;
case GL_FRAMEBUFFER_UNSUPPORTED: std::cout << "framebuffer unsupported" << std::endl; break;
case GL_FRAMEBUFFER_COMPLETE: std::cout << "framebuffer complete" << std::endl; break;
}
glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glFinish();
GLubyte pix[] = {0, 0, 0};
glReadPixels(0, 0, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, &pix);
std::cout << (int)pix[0] << " " << (int)pix[1] << " " << (int)pix[2] << std::endl;
當它運行時,它打印出'framebuffer complete',所以我假設framebuffer對象已經正確設置。但我期望調用glReadPixels可以讓我恢復我設置的清晰顏色(紅色) - 而不是返回黑色。
有什麼我在這裏失蹤?我試圖讓屏幕上的渲染工作在我的應用程序中拾取對象。