Problem enabling OpenGL ES depth test on iPhone. What steps are necessary?

Question

I remember running into this problem when I started using OpenGL in OS X. Eventually I solved it, but I think that was just by using glut and c++ instead of Objective-C...

The lines of code I have in init for the ES1Renderer are as follows:

glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);

Then in the render method, I have this:

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

I assume I'm missing something specific to either the iPhone or ES. What other steps are required to enable the depth test?

Thanks

Answer 1

#define USE_DEPTH_BUFFER 1 if you're using the OpenGL ES project template. This sets up a depth buffer somewhere in EAGLView.m.

Answer 2

You need to allocate the depth buffer itself. Allocate a new renderbuffer with the internal format DEPTH_COMPONENT16 or DEPTH_COMPONENT24, and attach it to the framebuffer object.

Answer 3

The instructions are here, if anyone else has this problem. The code is also below:

glGenRenderbuffersOES(1, &depthRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, 320, 480);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);

GLenum status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) ;
if(status != GL_FRAMEBUFFER_COMPLETE_OES) {
    NSLog(@"failed to make complete framebuffer object %x", status);
}