CAEAGLLayer *eagl_layer = (CAEAGLLayer *) view.layer;
  eagl_layer.opaque = TRUE;
  eagl_layer.drawableProperties = 
    [NSDictionary dictionaryWithObjectsAndKeys:
    [NSNumber numberWithBool:FALSE], kEAGLDrawablePropertyRetainedBacking,
    kEAGLColorFormatRGBA8,           kEAGLDrawablePropertyColorFormat,
    nil];
  ogl_ctx = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];

  ...

  [EAGLContext setCurrentContext: ogl_ctx];

  double s = self.contentScaleFactor;
  int w = s * [self frame].size.width;
  int h = s * [self frame].size.height;

  glGenFramebuffersOES  (1, &gl_framebuffer);
  glBindFramebufferOES  (GL_FRAMEBUFFER_OES,  gl_framebuffer);

  glGenRenderbuffersOES (1, &gl_renderbuffer);
  glBindRenderbufferOES (GL_RENDERBUFFER_OES, gl_renderbuffer);
  glRenderbufferStorageOES (GL_RENDERBUFFER_OES, GL_RGBA8_OES, w, h);
  glFramebufferRenderbufferOES (GL_FRAMEBUFFER_OES,  GL_COLOR_ATTACHMENT0_OES,
                                GL_RENDERBUFFER_OES, gl_renderbuffer);

#if 1 // #### why you no worky
  glGenRenderbuffersOES (1, &gl_depthbuffer);
  glBindRenderbufferOES (GL_RENDERBUFFER_OES, gl_depthbuffer);
  glRenderbufferStorageOES (GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES,
                            w, h);
  glFramebufferRenderbufferOES (GL_FRAMEBUFFER_OES,  GL_DEPTH_ATTACHMENT_OES, 
                                GL_RENDERBUFFER_OES, gl_depthbuffer);
#endif

  [ogl_ctx renderbufferStorage:GL_RENDERBUFFER_OES
           fromDrawable:(CAEAGLLayer*)self.layer];

  switch (glCheckFramebufferStatusOES (GL_FRAMEBUFFER_OES)) {
    ...

3 Responses:

1. Frode M says:

   11 years ago at 4:01 am

   I used something like this in my last opengles2 iOS app:
   
(...)
self.glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
(...)

   [EAGLContext setCurrentContext:self.glContext];
   glGenFramebuffers(1, &_glDefaultFramebuffer);
   glBindFramebuffer(GL_FRAMEBUFFER, _glDefaultFramebuffer);

   glGenRenderbuffers(1, &_glColorRenderBuffer);
   glBindRenderbuffer(GL_RENDERBUFFER, _glColorRenderBuffer);

   [self.glContext renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer*)self.layer];
   glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &_glFramebufferWidth);
   glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_glFramebufferHeight);

   glGenRenderbuffers(1, &_glDepthRenderBuffer);
   glBindRenderbuffer(GL_RENDERBUFFER, _glDepthRenderBuffer);
   glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, _glFramebufferWidth, _glFramebufferHeight);

   glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _glColorRenderBuffer);
   glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _glDepthRenderBuffer);

   glBindRenderbuffer(GL_RENDERBUFFER, _glColorRenderBuffer);

   GLenum glFramebufferStatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);


   • jwz says:

     11 years ago at 10:44 am

     Thanks! Looks like what I had wrong was that
     [ogl_ctx renderbufferStorage: ..etc...]
     has to come before
     glBindRenderbufferOES (GL_RENDERBUFFER_OES, gl_depthbuffer)
     and (I think?) the
     glRenderbufferStorageOES (GL_RENDERBUFFER_OES, GL_RGBA8_OES, w, h)
     is redundant with it.

     • Piku says:

       11 years ago at 2:58 pm

       Yeah that was really helpful. I'd somehow managed to get the
       
glGenRenderbuffers(1, &_glDepthRenderBuffer);
glBindRenderbuffer(GL_RENDERBUFFER, _glDepthRenderBuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, _glFramebufferWidth, _glFramebufferHeight);

       bit before the
       
glGenRenderbuffers(1, &_glColorRenderBuffer);

       and then totally miss out the
       
glBindRenderbuffer(GL_RENDERBUFFER, _glColorRenderBuffer);

       ... and still get an image (but with no depth buffer which really confused me when I tried using it in a shader).