The color correction cannot be done behind the back of the individual
instruction handlers because it might conflict with the instruction's
color modifications and the D3D provided writemask.
The fog settings do not depend on wether the shader writes to oFog or not,
instead they depend on the FOGVERTEXMODE and FOGTABLEMODE settings, and if a
vertex shader is bound at all.
It works the same way as with the fixed function, and having a vertex shader
is the same as using pretransformed vertices, just that the fog coord comes
from the shader instead of the specular color:
FOGTABLEMODE != NONE: The Z coord is used, oFog is ignored
FOGTABLEMODE == NONE, with VS: oFog is used
FOGTABLEMODE == NONE, no VS, XYZ: Z is used
FOGTABLEMODE == NONE, no VS, XYZRHW: diffuse color is used
Most callers work on a stateblock rather than a device, and the main fields
we check (vertexShader and pixelShader) are part of the stateblock as well.
This is a first step towards cleaning up the fog mess. The fog
parameter is added to the pixelshader compile args structure. That way
multiple pshaders are compiled for different fog settings, and the
pixel shader can remove the fog line if fog is not enabled. That way
we don't need special fog start and end settings, and this allows us
to implement EXP and EXP2 fog in the future too.
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.
Some stateblock parameters have to be compiled into the GL pixel
shader code, like lines for pixelformat fixups. This leads to problems
when applications switch those settings, requiring a recompilation of
the shader. This patch enables wined3d to have multiple GL shaders for
a D3D shader(pixel shaders only so far) to handle this more
efficiently.
This was suggested by Ivan quite a while ago, and we need it to better
handle conflicting texture format corrections and similar stateblock
value changes which until now required a recompilation of the entire
shader
A number of considerations contribute to this:
1) The shader backend knows best which shader(s) it needs. GLSL needs
both, arb only one
2) The shader backend may pass some parameters to the compilation
code(e.g. which pixel format fixup to use)
3) The structures used in (2) are different in vs and ps, so a
baseshader::Compile won't work
4) The structures in (2) are wined3d-private structures, so
having a public method in the vtable won't work(its a bad idea
anyway).
The code here skipped constant loading when a pixel shader was in use,
and only reloaded them on ffp use if the shader implementation used
ARB too. This way a e.g. texfactor change could get lost if GLSL
shaders are used, and the texfactor changed while a pixel shader was
in use.
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.
Henri Verbeet