Some games will set q to a different value than 1.0 through
texture matrix manipulations. It seems the console will still
do the division in that case.
Note: It's not 100% perfect, as some of the GPU capablities leak into the
pixel shader UID.
Currently our UIDs don't get exported, so there is no issue. But someone
might want to fix this in the future.
As much as possible, the asserts have been moved out of the GetUID
function. But there are some places where asserts depend on variables
that aren't stored in the shader UID.
Bug Fix: It was theoretically possible for a shader with depth writes
disabled to map to the same UID as a shader with late depth
writes.
No known test cases trigger this.
Bug Fix: The normal stage UIDs were randomly overwriting indirect
stage texture map UID fields. It was possible for multiple
shaders with diffrent indirect texture targets to map to
the same UID.
Once again, it dpesn't look like this bug was ever triggered.
This frees up 21 bits and allows us to shorten the UID struct by an entire
32 bits.
It's not strictly needed (as it's encoded into the length) but I added a
bit for per-pixel lighiting to make my life easier in the following
commits.
The only code which touches xfmem is code which writes directly into
uid_data.
All the rest now read their parameters out of uid_data.
I also simplified the lighting code so it always generated seperate
codepaths for alpha and color channels instead of trying to combine
them on the off-chance that the same equation works for all 4 channels.
As modern (post 2008) GPUs generally don't calcualte all 4 channels
in a single vector, this optimisation is pointless. The shader compiler
will undo it during the GLSL/HLSL to IR step.
Bug Fix: The about optimisation was also broken, applying the color light
equation to the alpha light channel instead of the alpha light
euqation. But doesn't look like anything trigged this bug.
Drivers that don't support GL_ARB_shading_language_420pack require that
the storage qualifier be specified even when inside an interface block.
AMD's driver throws a compile error when "centroid in/out" is used within
an interface block.
Our previous behavior was to include the storage qualifier regardless, but
this wasn't working on AMD, therefore we should check for the presence of
the extension and include based on this, instead.
OS X's shader compiler has a bug with interface blocks where interface block members don't properly inherit the layout qualifier from the interface
block.
Work around this limitation by explicitly stating the layout qualifier on both the interface block and every single member inside of that block.
Fast depth is now more accurate than slow depth and should always be used.
The option will be kept in a different form as it is still used as a hack to fix some games.
Also, the slow depth code path will still be relied upon by cards that don't support GL_ARB_clip_control.
Jules Blok