Apple's GLSprite OpenGL ES Sample App

Nibbie
Posts: 2
Joined: 2009.04
Post: #1
I am going through Apple's GLSprite OpenGL ES sample app attempting to figure out how the code works.

In EAGLView.m there is method createFrameBuffer:

Code:
- (BOOL)createFramebuffer
{
    glGenFramebuffersOES(1, &viewFramebuffer);
    glGenRenderbuffersOES(1, &viewRenderbuffer);
    
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
    [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(id<EAGLDrawable>)self.layer];
    glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);
    
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
    glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
    
    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;
}

What do the procedure calls glGenFramebuffersOES and glGenRenderbuffersOES do?

I see they are in Apple's OpenGL ES framework (OpenGLES.framework/Headers/ES1/gl.h), but I can't find either in Apple's documentation under Xcode, on their Developer site or in the man pages on khronos.org, which makes it difficult figuring out how the code works.
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Member
Posts: 86
Joined: 2008.04
Nibbie
Posts: 2
Joined: 2009.04
Post: #3
Cool, thanks!
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