Question

I am having some problem with the creation of frame buffer with opengles.
For my application, I create the main frame buffer like this:

glGenFramebuffers( 1, &viewFramebuffer );
glGenRenderbuffers( 1, &viewRenderbuffer );

glBindFramebuffer( GL_FRAMEBUFFER, viewFramebuffer );
glBindRenderbuffer( GL_RENDERBUFFER, viewRenderbuffer );
[ Context renderbufferStorage : GL_RENDERBUFFER fromDrawable : ( CAEAGLLayer* )self.layer ];
glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, viewRenderbuffer );

glGetRenderbufferParameteriv( GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &backingWidth );
glGetRenderbufferParameteriv( GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &backingHeight );

if ( itUsesDepthBuffer )
{
    glGenRenderbuffers( 1, &depthRenderbuffer );
    glBindRenderbuffer( GL_RENDERBUFFER, depthRenderbuffer );
    glRenderbufferStorage( GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, backingWidth, backingHeight );
    glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer );
}

if ( glCheckFramebufferStatus( GL_FRAMEBUFFER ) != GL_FRAMEBUFFER_COMPLETE )
{
    NSLog( @"failed to make complete framebuffer object %x", glCheckFramebufferStatus( GL_FRAMEBUFFER ) );
    [ self destroyFramebuffer ];

    return NO;
}

But the function glGetRenderbufferParameteriv returns 0 either for GL_RENDERBUFFER_WIDTH and GL_RENDERBUFFER_HEIGHT and eventually the glCheckFramebufferStatus returns an error as framebuffer attachment is incomplete.

Do you have any idea why is this happening?

Thank you in advance.

Answer 1

Ok I fixed it, it was failing to render the buffer storage:

[ Context renderbufferStorage : GL_RENDERBUFFER fromDrawable : ( CAEAGLLayer* )self.layer ];

For some reason my “self.layer” was not returning the correct one.