Re: GLX in bad state

ons, 11.02.2004 kl. 13.55 skrev Nadav Frum:
> In MS-Win multi-pass renderings are done by rendering directly onto a 
> texture and then using this texture.  The OpenGL extension which allows 
> this to be done is called WGL_ARB_render_texture.  There is no equivalent 
> extension in GLX.
> 
> WineX does not render directly onto the texture.  A suitable off-screen 
> rendering target (called a pixel buffer) is chosen and rendered into.  The 
> result is then transferred into the texture.  By my calculation this 
> transfer of pixels into the relevant textures can reach several hundreds 
> of MBytes per second.  It consumes valuable video memory bandwidth and 
> impairs (sometimes cripples) performance.  
> 
> I think the WineX community should support getting valuable WGL extensions
> translated into GLX.  Otherwise, Linux gaming will always be at a considerable
> disadvantage in comparison to MS-Win.

I had the impression that the ARB has been working on a
GLX_ARB_render_texture for some time now. But they do seem a little bit
slow about it... perhaps they're too focused on OpenGL 2.0.

But I hear that the current OpenGL 2.0 draft also has a bunch of issues
that will be a problem for WineX. Peter might know more about that.

Note that the ATI FireGL drivers have an undocumented ATI_render_texture
extension, perhaps we could use that when ATI releases new drivers that
WineX does not have so many issues with. But obviously that wouldn't
solve the problem for nvidia cards.