>> > Well, I'll consider having a look at it.
>>
>> You should, because this extension is / will be _the_ way to do
>> render-to-texture with opengl. previous methods are slower (require
>> context-switches) and they depend on windowing system (glx, wgl, agl).
>>
>> EXT_fbo is cross-platform, fast and does not require any windowing-system 
>> specific
>> calls..
>>
>> The basic idea behind EXT_fbo is, that you can bind textures (any
>> mipmap-level, or slice of 3d-texture) as framebuffer (color, stencil or
>> depth -buffer) and then all the rendering operations operate on the texture
>> rather than real framebuffer. Simple and clean.
>
> It's like they finally thought "hey, we should have arbitrary
> off-screen surfaces that you can render to... and FROM."  Finally,
> after all this time, they reinvented the Pixmap.  :)

This was possible already using pbuffers/GLX.

[...]
>> > Hey, I just realized that we don't have any mechanism to make the
>> > hardware generate MIPmaps.  I was going to have it when I was going to
>> > include an antialias multisample stage, but that got nixed by the
>> > experts.
>> >
>> > Suggestions?
>>
>> Take a look at GL_SGIS_generate_mipmap:
>>
>> http://oss.sgi.com/projects/ogl-sample/registry/SGIS/generate_mipmap.txt
>>
>> At least that's how you generate mipmaps using hardware-acceleration in 
>> opengl..
>
> Well, that looks like a command.  I need an algorithm.
>
> But Nicolai gave me a good solution for that.  It involves minifying a
> texture with linear filter.  If you offset it right, it'll do all the
> right blending automatically.

I think OpenGL suggests using a box filter for this.


--ms

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