This is the prefered format of many codecs, and for some codecs this
is the only supported output format. As usual I try to handle all the
conversion in the GPU and keep the CPU involvement minimal to gain the
full performance of PBO transfers.
GL_ARB_fragment_program and GL_ATI_fragment_shader can disable
projected textures properly, and they can also handle
D3DTTFF_PROJECTED | D3DTTFF_COUNT3 properly.
If we're heading out of the pixelshader handler early, and a pixel
shader is in use, the pixel shader may not be compiled. The vertex
shader handler then checks if the pixel shader is dirty, and calls the
shader backend to apply the shader if it isn't. Thus, in the case of
GLSL, the shader code could attempt to link an uncompiled shader into
the program. This isn't much of a problem because when the fog is
applied, the pixel shader is compiled and the program re-linked.
If a format is not supported natively by opengl, a shader may be able
to convert it. Up to now, CheckDeviceFormat had magic knowldge which
GL extensions lead to which supported format. This patch adds
functions that allow CheckDeviceFormat to ask the actual
implementation for its capabilities.
Fixed function processing can only deal with values between 0 and 1
generally. Clamp the results of instructions that could produce bigger
or smaller values.
This is an ATI specific format designed for compressed normal maps,
and quite a few games check for its existence. While it is an
ATI-specific "extension" in d3d9, it is a core part of
D3D10(DXGI_FORMAT_BC5), and supported on Geforce 8 cards.
It isn't related to the shader backend any longer. The nvts_enable in
the ffp code isn't quite right as well, it should be moved away once
there is a dedicated nvts fragment pipeline replacement
Calling shader_select() from inside depth_blt() isn't necessarily
safe. shader_select() assumes CompileShader() has been called for the
current shaders, but that depends on STATE_VSHADER / STATE_PIXELSHADER
being applied. That isn't always true when depth_blt() gets called,
with the result that sometimes GLSL programs could be created with no
shader objects attached.
Constant numbers start at 0, and the loading loop has a for(i; i <
dirtyconsts; i++). This means that the highest dirty constant isn't
loaded correctly. Rather than replacing the < with <=, which would
make it impossible to have no dirty constant, add 1 to the dirty
constant counter.
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
Roderick Colenbrander