Nvidia doesn't offer it on geforce 7 and earlier cards, but some games need
it. This is surprising because the extension was made specifically for
compatibility purposes for older cards.
These surfaces won't be attached to an FBO anyway, so avoid the cost of a
potential format conversion when blitting from a non-RT surface. This is
mostly an issue for ddraw applications with 16 bit render targets.
Add a new wined3d-internal PreLoad function to textures and surfaces
that takes a parameter specifying wether the rgb or srgb texture
should be loaded.
This reduces the number of srgb switching reloads quite a lot. The only
situation in which a reload is needed is if the rgb copy is modified on the GL
side and the srgb copy is needed.
We cannot remove this because we still have to load the surface as
RGB. The shader may take care of setting the blue channel to 1.0 now,
but we still get the red and green channels loaded incorrectly if we
don't insert a blue channel before loading.
This allows us to drop the load time conversion and the clear
readback hack and replaces it with a color fixup in the fixed
function pipeline replacement.
Based on a patch by Stefan Dösinger. This is more flexible, and allows
the shader backend implementation to be simpler, since it doesn't have
to know about specific formats. The next patch makes use of this.
Note that minMipLookup and magLookup aren't particularly safe to use,
they're global arrays initialized from IWineD3DImpl_FillGLCaps(). The same
goes for the other global dynamic lookup tables.
GL_ATI_envmap_bumpmap provides two things: Signed V8U8 pixel formats,
and bump mapping. The extension is only supported on fglrx, and this
driver also supports GL_ARB_fragment_program. Thus the bump mapping
code is never used on any driver out there. Furthermore, if it is
used, it tends to crash the driver
The signed pixel format is used, as it can be used by pixel shaders or
the ARBfp replacement. However, the format is broken in fglrx, and
negative values are clamped to 0.0. This results in test
failures. WineD3D has an alternative codepath using scale+bias to
enable V8U8 using a standard signed RGB which works correctly on
fglrx.
Francois Gouget