commit f92ce4f62586a355daa2c43f3599ea0d325bb4a2
author Arman Uguray <armansito@google.com> Fri Mar 17 11:46:32 2023 -0700
committer SkCQ <skcq-be@skia-corp.google.com.iam.gserviceaccount.com> Fri Mar 17 20:04:37 2023 +0000
tree f9020da8b678a5ee13adb9249b73e713aebbd0fb
parent 49b902e5fb9188919ac3f9b00efafe2e49391c7a

[ganesh][dawn] Disable derivative uniformity warnings

This disables derivative uniformity analysis in the Ganesh Dawn backend.

Change-Id: I8292943e8adf989a5ff5031c8ef562d03821855a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/658116
Commit-Queue: Arman Uguray <armansito@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>

src/gpu/ganesh/dawn/GrDawnGpu.cpp

diff --git a/src/gpu/ganesh/dawn/GrDawnGpu.cpp b/src/gpu/ganesh/dawn/GrDawnGpu.cpp
index c2f6565..37bc72b 100644
--- a/src/gpu/ganesh/dawn/GrDawnGpu.cpp
+++ b/src/gpu/ganesh/dawn/GrDawnGpu.cpp
@@ -1027,12 +1027,19 @@
 }
 
 wgpu::ShaderModule GrDawnGpu::createShaderModule(const std::string& spirvSource) {
-    wgpu::ShaderModuleSPIRVDescriptor desc;
-    desc.codeSize = spirvSource.size() / 4;
-    desc.code = reinterpret_cast<const uint32_t*>(spirvSource.c_str());
+    wgpu::ShaderModuleSPIRVDescriptor spirvDesc;
+    spirvDesc.codeSize = spirvSource.size() / 4;
+    spirvDesc.code = reinterpret_cast<const uint32_t*>(spirvSource.c_str());
 
-    wgpu::ShaderModuleDescriptor smDesc;
-    smDesc.nextInChain = &desc;
+    // Skia often generates shaders that select a texture/sampler conditionally based on an
+    // attribute (specifically in the case of texture atlas indexing). We disable derivative
+    // uniformity warnings as we expect Skia's behavior to result in well-defined values.
+    wgpu::DawnShaderModuleSPIRVOptionsDescriptor dawnSpirvOptions;
+    dawnSpirvOptions.allowNonUniformDerivatives = true;
 
-    return fDevice.CreateShaderModule(&smDesc);
+    wgpu::ShaderModuleDescriptor desc;
+    desc.nextInChain = &spirvDesc;
+    spirvDesc.nextInChain = &dawnSpirvOptions;
+
+    return fDevice.CreateShaderModule(&desc);
 }