Using depth buffer on iOS with OpenGL ES 1.1 - iphone

Question

I'm trying to get a depth buffer working so I can start making a game for iOS. I'm fine with OpenGL and Objective-C for OSX but this is my first time making an iphone application.
I removed the ES1Renderer and ES2Renderer classes and moved the ES1 code into the EAGLView class. The default animation worked when I did that. When I tried to use perspective it went wrong. I get a white screen now. Can someone tell me what I'm doing wrong?
In the initialisation method:
// Create default framebuffer object.
glGenFramebuffersOES(1, &defaultFramebuffer);
glGenRenderbuffersOES(1, &colorRenderbuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, defaultFramebuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, colorRenderbuffer);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, colorRenderbuffer);
//Initialisation code for the game's graphics and to develop the scene
glEnable(GL_DEPTH_TEST); //Enables Depth Testing
glDepthFunc(GL_LEQUAL);
glDepthMask(GL_TRUE);
//glEnable(GL_CULL_FACE);
//glCullFace(GL_FRONT);
//Setup projection matrix
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
double xmax = 0.04142135624 * ((float) backingWidth)/backingHeight;
glFrustumf(-xmax, xmax, -0.04142135624, 0.04142135624, 0.1, 2000); //The ymax and min have been precalculated
glMatrixMode(GL_MODELVIEW); //Select The Modelview Matrix
glLoadIdentity();
In the drawView method:
static const GLfloat squareVertices[] = {
1, 1,-0.1f,
-1, 1,-0.1f,
1, -1,0.1f,
-1, -1,0.1f,
};
static const GLubyte squareColors[] = {
0,0,200,255,
40,90,250,255,
0,0,200,255,
50,100,230,255,
};
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_DEPTH_BUFFER_BIT);
glVertexPointer(3, GL_FLOAT, 0, squareVertices);
glEnableClientState(GL_VERTEX_ARRAY);
glColorPointer(4, GL_UNSIGNED_BYTE, 0, squareColors);
glEnableClientState(GL_COLOR_ARRAY);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
In the layoutSubviews method:
// Allocate color buffer backing based on the current layer size
glBindRenderbufferOES(GL_RENDERBUFFER_OES, colorRenderbuffer);
[context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*) self.layer];
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
glGenRenderbuffersOES(1, &depthRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);
if (glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES)
{
NSLog(#"Failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) );
return NO;
}
return YES;
[self drawView:nil];
I've done everything it seems I have to do. I don't know why it's so much more complicated for iOS.
Thankyou for any help.

Answer 1

Have a look at the code you can find at this page the author inits an EAGLView subclass parametrizing the method in the case he needs a depth buffer

Answer 2

I might be reading this wrong, but you are defining a clipping box with:
glFrustumf(-xmax, xmax, -0.04142135624, 0.04142135624, 0.1, 2000);
And the object that you're trying to render with:
static const GLfloat squareVertices[] = {
1, 1,-0.1f,
-1, 1,-0.1f,
1, -1,0.1f,
-1, -1,0.1f,
};
At the top you are clipping Z values from 0.1 to 2000.
But your vertices have Z values from -0.1 to 0.1.
These don't see to overlap.
You might want to try moving the object that you want
to look at into the area where you can see it.