Adreno material shader fixes #8589
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May 9, 2023 12:54
On certain Adreno chipsets (such as the 619) the `StandardMaterial` flags are capped for some reason thus producing issues with how alpha is being processed. Specifically all meshes were treated by the `bevy_pbr` shader as being opaque. Moving them to below 16-bits solved the issue and since there is nothing used above bit-index 9 it should be safe for all platform/chipsets.
This is useful when targetting certain mobile gpus (Qualcomm/Adreno) on WebGL. The shader will currently crash when set to the default 10. Possibly related to some memory issue in the gpu drivers.
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james7132
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Both of the linked issues seem to have been fixed by #8508, so I think this can be closed. |
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Objective
Address some issues afflicting the Adreno series of GPUs, specifically on WebGL.
Alpha blending is broken for these GPUs since the standard blending changes were merged.
Also there is an issue related to directional lights and fog.
Fixes #8506
Fixes #8047
Solution
The first issue in relation to alpha blending was a weird one. It could be fixed by moving the flags for the alpha blending from the end of the
u32to just after the last flag from the beginning instead. This seems to be because of some differences in the memory mapping, probably at a lower level. However this fix should work for all other architectures as well.The second issue is also weird and potentially also related to some as of yet unknown issue with how data is passed between the CPU and the GPU. My best guess is that it is an issue with the Adreno shader compiler that messes up since
gpu_directional_lightsis an array of 10 by default and it either tries to do some fancy pre-optimization or fumbles when the data is copied over to the gpu here as well. The simplest solution I could think of that works without requiring major changes that would affect all platform is to add a feature that can be passed along if you for some reason need to have your code running specifically on these types of GPUS. Thus I added thelimit_directional_lightfeature that limits the directional lights to 1 but by default it still stays at 10.Changelog
limit_directional_lightfeature that limits the amount of directional lights to one because of issues with the Adreno chipset and fog.