wined3d: Allow WINED3DFMT_R32F render targets

[Chris Robinson]

On Sunday 14 October 2007 02:57:35 am H. Verbeet wrote:
> On 14/10/2007, Chris Robinson <chris.kcat at gmail.com> wrote:
> > May need more work for this to be proper, but we currently allow R16F
> > render targets under the same circumstances. It's also enough to make UT3
> > (which requires it) happy.
>
> Unless the performance problems with R32F have been fixed, this will
> cause performance regressions in applications that actually try to use
> it. (C&C3 for example).

With some other fixes, it may work better using pbuffers where there are 
possibly R32F formats available. Unfortunately, by oversight or design, GL 
has no renderable single-component formats* so we have to fall back to 
R32G32B32F, which could be a bit harder on the hardware. Most apps seem to 
only use it for shadow mapping though, so perhaps using a 32-bit depth 
texture would work? And maybe use depth textures for R16F as well.

* There is the NV extension which gives 16 and 32-bit Red-only renderable 
formats, but that has other issues, namely having to use 
GL_TEXTURE_RECTANGLE_NV which causes the texture's coords to behave 
differently. Plus it won't work on non-NV hardware.