SM3.0 requires 10 4 component float varyings for passing stuff between
vertex and pixel shaders. GF7 and earlier report 8 generic varyings +
gl_Color and gl_SecondaryColor in GLSL. This patch allows us to use
gl_Color and gl_SecondaryColor to get 2 extra varyings, which some
games, like C&C3 with highest gfx settings, require.
The previous logic assumed that if NVTS or ATIFS are available they
will be used. This happens to be true for NVTS, but ATIFS is only used
if neither ARBFP nor GLSL are supported. This breaks fixed function
fragment processing on ATI r300 and newer cards
Since the shader backend implementations might track opengl resources in
their private data inform them about reset calls. For example, the atifs
backend keeps track of the replacement shaders, which are lost during an
opengl context recreation.
The whole control structures in directx.c get terribly confusing with
the various codepaths for texturing and different shader
implementations. It is also hard to reflect the shader model
decisions this way too. This patch moves the shader specific parts of
the caps code into the shader backend where we can set our caps
dependent of the shader model decisions and without complex caps flag
checks.
Generating the shader ID and parts of the shader prolog and epilog was
done by the common vertexshader.c / pixelshader.c, which is ugly.
This patch doesn't get rid of all the uglyness, somewhen we'll still
have to sort out the relationship of [arb|glsl]_generate_shader and
[arb|glsl]_generate_declarations.
Add a new property of the shader backend which indicates whether the
shader backend is able to dirtify single constants rather than
dirtifying vshader and pshader constants as a whole. Depending on this
a different Set*ConstantF implementation is used which marks constants
dirty. The ARB shader backend uses this and marks constants clean
after uploading.
The GL_ARB_vertex_program extension does not define a standard value for
output texture coordinates. This makes problems when using vertex
shaders with fixed function fragment processing because fffp divides the
texture coords by its .w component. This means that gl shaders have to
write to the .w component of texture coords. Direct3D shaders however
do not.
H. Verbeet