[iPhone] Why framebuffer is used in OpenGL ES examples ??

Hi.
I'm quite new to the OpenGL ES on iPhone.
In the OpenGL ES sample codes, the rendering seems to be performed like this:
[EAGLContext setCurrentContext:context];
glBindFramebufferOES(GLFRAMEBUFFEROES, viewFramebuffer);
... Draw something...
glBindRenderbufferOES(GLRENDERBUFFEROES, viewRenderbuffer);
[context presentRenderbuffer:GLRENDERBUFFEROES];
When I removed the framebuffer part, the application shows nothing.
Is there any reason to do rendering through a framebuffer ?
Or, is this how OpenGL ES scene is rendered on a view ?

I am no sure I understand your problem, especially because glTexImage2D is available. Such are glMultiTexCoord and glActiveTexture. Were you talking about glDrawPixels (which is not)?
You could also grab data with glReadPixels and after a few computations send them back as a new texture.
Not sure I can help, but it will at least be a 'up'.

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I'd like to continue the below thread about "why not to use static methods"
Why not to use static methods
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