On Tue, Jan 18, 2005 at 09:52:25AM -0500, Timothy Miller wrote:
> 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.
 
> To the hardware a texture is just a memory area from which you can
> read or write.  The only thing we have to worry about is syncing the
> pipeline when you decide you want to read from something you just
> wrote to (latency).  Oh, and if MIPmapping is involved, the driver
> will have to regenerate them.
> 

Yep. 

> 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..

-- Pasi K�rkk�inen
       
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                                .     .
                                 Linux
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                             Choice.of.the
                           .Next.Generation.
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