The game tries to use anisotropic filtering deep in some control flow
while updating a procedural displacement map, our sampling hardware
does not check the channel enable mask before calculating the
derivatives for each subspan, which causes it to get garbage for any
subspans that have partially disabled lanes.
This workaround converts any sample messages in fragment shaders that
have divergent control flow into a sample_d message with the derivatives
zero'd by software if some of the lanes are disabled.
Closes: #12796
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41716>
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