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
Mesa has a bug that causes a crash due to a NULL pointer dereference
with the R200 driver when making a context current that has
GL_FRAGMENT_SHADER_ATI enabled. This patch works around this bug by
making sure that GL_FRAGMENT_SHADER_ATI is disabled before deactivating
a context, and reactivates it afterwards. The context manager keeps
GL_ATI_FRAGMENT_SHADER generally enabled, except if the context is in 2D
blit mode.
For each pixel format we store a flag in the table whether it supports
post pixelshader blending. Before applying blending or during a
context switch we verify that blending is turned off for the
format. In case of R32F this gave a 5-6x performance boost (without
filtering and software conversion).
This adds code for handling fixed function fragment processing with the
GL_ATI_fragment_shader extension. This is a sort-of programmable
interface for fragment processing at the level of shader model 1.4 in
d3d. This code is of use on r200, r250 and r280 cards(radeon 8500 to
9200) which do not support GL_ARB_fragment_program, but support pixel
shader 1.4 on Windows. This code is somewhat a counterpart to the
existing fragment processing code using GL_NV_register_combiners and
GL_NV_texture_shader.
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.
Before it was done in findContext, before selecting the new context
which is bad (it doesn't always work). The new code works and this
change also fixes some draw buffer regressions that happened during
the surface rewrite from the last couple of days.
