| Summary: | [radeonsi] blue ground in Company of Heroes 2 | ||
|---|---|---|---|
| Product: | Mesa | Reporter: | Laurent carlier <lordheavym> |
| Component: | Drivers/Gallium/radeonsi | Assignee: | Default DRI bug account <dri-devel> |
| Status: | VERIFIED FIXED | QA Contact: | Default DRI bug account <dri-devel> |
| Severity: | normal | ||
| Priority: | medium | ||
| Version: | git | ||
| Hardware: | x86-64 (AMD64) | ||
| OS: | Linux (All) | ||
| See Also: | https://bugs.freedesktop.org/show_bug.cgi?id=94835 | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
| Bug Depends on: | 94835 | ||
| Bug Blocks: | |||
| Attachments: | battlefield with some blue ground | ||
|
Description
Laurent carlier
2016-03-25 17:25:35 UTC
Hi Laurent, thanks for the report. I did some digging into the apitrace you provided. Long story short: The game does not properly deal with the implementation-defined limit on the number of samplers that are available in a fragment shader. Perhaps there is some graphics quality setting that can be reduced to convince the game to use only shaders with fewer samplers as a workaround. The long story: In the provided apitrace, the artefacts first appear in textures 10884 and 10885, which are terrain colour and normal maps. They are rendered to around call @516614, which is a glLinkProgram call for program 658 that fails because the attached fragment shader 611 has not been compiled. It is evident from the trace leading up to @516933 that the game intends to do rendering using 658 precisely when the artefacts appear, because there are a bunch of (failing) calls to query uniform locations. Why has shader 611 not been compiled? Well, most likely there is logic in the game that does check for implementation-defined sampler limits, because shader 611 uses 18 samplers and we only expose 16. So probably some part of the game engine notices the limitation and doesn't even try to compile the shader, but this problem is not propagated up to higher layers in the engine. This issue is caused by Mesa not exposing more than 16 samplers, once Mesa supports more samplers then Mesa will start to render correctly. There is no simple way of downgrading the engine to avoid this issue. We have request that the Mesa limitation is removed so Mesa can support more samplers like other drivers. Please Note: We can help developers working on this issue with a Steam key and other details as needed. I agree that it makes sense to raise the limit for the long run. I'll take a look into that. I have logged a specific bug for this request here along with some extra information that might come in handy when implementing this: https://bugs.freedesktop.org/show_bug.cgi?id=94835 I have also marked this bug as depends on 94835. We now support up to 32 samplers in Git master as of commit 2abe4f8d7dcdcff75c28958e1a691ebf6cdee1ac Verified as working using the latest git. |
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