Looks like the list server bounced this.
---------- Forwarded message ---------- From: Timothy Miller <[EMAIL PROTECTED]> Date: Tue, 18 Jan 2005 12:38:23 -0500 Subject: Re: [Open-graphics] new opengl render-to-texture extension: GL_EXT_framebuffer_object To: Pasi K�rkk�inen <[EMAIL PROTECTED]> Cc: [email protected] On Tue, 18 Jan 2005 18:29:33 +0200, Pasi K�rkk�inen <[EMAIL PROTECTED]> wrote: > 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. 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. :) > > > 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.. 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. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
