iOS Very Basic OpenGL ES problem

[Soulstorm]

I am trying to do some basic OpenGL ES with my iPhone, but I have some problems doing so. In my Xcode, I have created a new OpenGL ES based application project and I have changed the drawView function in the EAGLView.m file to look like this:

- (void)drawView {
	
	glEnable(GL_DEPTH_TEST);
	
	[EAGLContext setCurrentContext:context];
	glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
	glViewport(0, 0, backingWidth, backingHeight);
	
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	
	glOrthof(-100.0f, 100.0f, -150.0f, 150.0f, -100.0f, 100.0f);
	
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	static GLfloat rotation = 0.0f;
	
	glRotatef(rotation, 0.0f, 1.0f, 0.0f);
	rotation += 1.0f;

	glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	
	const GLfloat squareVertices[] = {
		-50.0f, -50.0f, -1.0f,
		50.0f,  -50.0f,	-1.0f,
		-50.0f,  50.0f, -1.0f,
		50.0f,   50.0f, -1.0f,
	};
	
	glColor4f(1.0f, 0.0f, 0.0f, 1.0f);
	glVertexPointer(3, GL_FLOAT, 0, squareVertices);
	glEnableClientState(GL_VERTEX_ARRAY);
	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
	
	
	
	
	const GLubyte squareColors[] = {
        255, 255,   0, 255,
        255, 255,   0, 255,
        0,     0,   0,   0,
        255,   0, 255, 255,
    };
	
	glColorPointer(4, GL_UNSIGNED_BYTE, 0, squareColors);
	glEnableClientState(GL_COLOR_ARRAY);
	
	const GLfloat squareVertices2[] = {
		-40.0f, -40.0f, -12.0f,
		40.0f,  -40.0f, -12.0f,
		-40.0f,  40.0f, -12.0f,
		40.0f,   40.0f, -12.0f,
	};
	
	glVertexPointer(3, GL_FLOAT, 0, squareVertices2);
	glDrawArrays(GL_TRIANGLE_STRIP,0, 4);
	
	
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

Although I can get my two rotating squares, when the rotation is 180 degrees, the smaller square still seems to be in front of the bigger one, but this should not happen... I know the answer is simple but I can't find it! I have already enabled GL_DEPTH_TEST as you can see. The same thing happens if I try setting the z value of the smaller square to something else (like a positive value).

Can anyone help?

 

[lazydog]

Did you create your framebuffer with a z buffer?

ß e n