iOS OpenglES 3.0 渲染到纹理失败并带有深度附件

Question

当 rendertarget 纹理没有深度附件时，在我的移动应用程序中渲染到纹理可以正常工作。 当我添加深度附件时，它停止在 iOS 上工作。 显然无法切换回原始渲染目标或其附加的深度缓冲区，并且图像冻结，声音继续。 它在 Android 上运行良好。

//配置：

glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING_APPLE, &backbuffer); 
glGetIntegerv(GL_FRAMEBUFFER_BINDING,&backbuffer); // tried both


glGenFramebuffers(1, &fbo);
glGenTextures(1, &texture);
glGenRenderbuffers(1, &depthbuffer);

glBindFramebuffer(GL_FRAMEBUFFER, fbo);


glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D( GL_TEXTURE_2D,0,GL_RGBA,resx,resy,0,GL_RGBA,GL_UNSIGNED_BYTE,NULL);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER_APPLE, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);

glBindRenderbuffer(GL_RENDERBUFFER, depthbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, resx, resy);
glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER_APPLE, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthbuffer);


GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);

// 渲染进去

glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glViewport(0, 0, resx, resy);
  ...

// 继续渲染到主屏幕：

     glBindFramebuffer(GL_FRAMEBUFFER, backbuffer); 
     glViewPort(0,0,screenX,screenY);

// 如果有深度附件，显然不会变回后台缓冲区

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更新：找到解决方案：完成将渲染缓冲区附加到新帧缓冲区后，必须解除绑定。 奇怪的是 Android 和 Linux 并不关心离开渲染缓冲区绑定。

GLint origRenderBuffer;
glGetIntegerv(GL_RENDERBUFFER_BINDING,&origRenderBuffer);
.....// create FBO with attachment here.
glBindRenderBuffer(GL_RENDERBUFFER,origRenderBugger);