渲染爲紋理：始終爲黑色紋理

Question

我在嘗試渲染紋理，隨後使用紋理，但由於某種原因它不起作用。

如蘋果documentation描述，

首先我分配FBO的紋理渲染..

glGenFramebuffers(1, &read_framebuffer); 
glBindFramebuffer(GL_FRAMEBUFFER, read_framebuffer); 

然後創建紋理並將其連接到該FBO ..

glActiveTexture(GL_TEXTURE0); 
glGenTextures(1, &texture); 
glBindTexture(GL_TEXTURE_2D, texture); 
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); 
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); 
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); 
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8_OES, 64, 64, 0, GL_RGBA, 
      GL_UNSIGNED_BYTE, NULL); 
glBindRenderbuffer(GL_RENDERBUFFER, 0); 
glBindTexture(GL_TEXTURE_2D, 0); 
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 
         texture, 0); 

然後創建用於繪製的fbo ..

glGenFramebuffers(1, &draw_framebuffer); 
glBindFramebuffer(GL_FRAMEBUFFER, draw_framebuffer); 
glGenRenderbuffers(1, &_colorRenderBuffer); 
glBindRenderbuffer(GL_RENDERBUFFER, _colorRenderBuffer); 
[_context renderbufferStorage:GL_RENDERBUFFER fromDrawable:_eaglLayer]; 
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _colorRenderBuffer); 

在渲染循環的一部分後來..

glBindFramebuffer(GL_FRAMEBUFFER, read_framebuffer); 

(...off-screen drawing the scene here...) 

glBindFramebuffer(GL_FRAMEBUFFER, draw_framebuffer); 

綁定它應該包含我的屏幕外渲染圖像紋理..

glBindTexture(GL_TEXTURE_2D, texture); 

(..draw the scene with texture applied here...) 

但是，由於某種原因，質感始終是黑色的。有什麼我在這裏失蹤？

Answer 1

在glTexImage2D交換GL_RGBA8_OES對於GL_RGBA。我可以看到你從蘋果文件中獲取這些參數..（無評論..）無論如何，關於你的問題的意見，正如@prideout指出的，你應該總是檢查幀緩衝區狀態。在你的情況下，它返回GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT。