[GEM-dev] some new code

[James Tittle II]

On Sep 15, 2004, at 12:10 PM, chris clepper wrote:

> On Sep 15, 2004, at 10:06 AM, r.leboite.pm at birdsinplane.com wrote:
>>
>>
>> Well the main extension i added is the possibility to render to a 
>> texture using
>> the extension WGL_ARB_RENDER_TEXTURE which works pretty well now.
>>
>> I also coded some tests about Cg Vertex Programs. Those programs work 
>> quite
>> well but are not yet enough flexible to be commited.
>
> Specifically, render-to-texture is part of the multiple windows and 
> targets, and I think we will look at pBuffers to help achieve this.  
> As for shaders, I would prefer not to use Cg for two reasons: one it's 
> not part of ARB OpenGL, and not equally supported between platforms or 
> vendors.  Also, I think GLSL has potentially a superior architecture, 
> although it might take ages for it to even be implemented fully on all 
> three of GEM's target platforms.  Both of these projects are still 
> really in the planning stages, and various people are experimenting 
> with potential solutions.

...I'm not familiar much with the ARB_Render_Texture api:  a quick look 
at apple's OGL extensions guide doesn't list it, so that's a strike 
against implementing it in GEM (maybe it's covered under something 
else)...we'd already planned on doing other offscreen rendering targets 
via pbuffers...

...I'm not against have Cg capabilities, I just know from experience 
that it can be tricky to use cross-platform, and pretty much forget 
about using it with ATI cards (they have much different 
expectations)...that said, how are you implementing it?  Are you 
intending to use the Cg runtime?  I'd really be against that at this 
point...

...otoh, GLSL will definitely get implemented, but it's not available 
atm on OSX, so we're waiting...until then, what I've been working 
towards is just supporting the loading of ARB_vp and ARB_fp programs, 
which we can definitely do crossplatform atm...of course, this means 
that you have to write the shader in something other than the nicely 
intelligible GLSL or Cg :-)

> You should become a developer since you are interested in working on 
> advanced features, and also seem to be working on Windows.  It would 
> be good to have someone to help out with the render targets and 
> shading, and you will get some help with figuring out GEM's internal 
> architecture.

...I agree:  at this point, you should make the code available 
somewhere online, or send it to the list (or just me:  is anyone else 
working on this, too?) perhaps...then we can set up a branch to deal 
with these, get ya access, and then start digging!

james