WebGPURenderer: Fix VSM shadow artifacts. #32327
Merged
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Related issue: #31885
Description
This PR fixes visual artifacts (black/white noise) when using
VSMShadowMapinWebGPURenderer.The issue was caused by floating point precision errors in the variance calculation. Occasionally,
squaredMean - mean * meanwould result in a slightly negative value. When passed tosqrt(), this producedNaNvalues that propagated through the shadow calculation.The fix clamps the variance value to
0before the square root operation, ensuring valid results.(Made using https://antigravity.google/ with Gemini 3.0)