shader: Implement SampleMask

src/shader_recompiler/backend/spirv/emit_context.cpp

@@ -1179,7 +1179,10 @@ void EmitContext::DefineOutputs(const IR::Program& program) {
         if (info.stores_frag_depth) {
             frag_depth = DefineOutput(*this, F32[1], std::nullopt);
             Decorate(frag_depth, spv::Decoration::BuiltIn, spv::BuiltIn::FragDepth);
-            Name(frag_depth, "frag_depth");
+        }
+        if (info.stores_sample_mask) {
+            sample_mask = DefineOutput(*this, U32[1], std::nullopt);
+            Decorate(sample_mask, spv::Decoration::BuiltIn, spv::BuiltIn::SampleMask);
         }
         break;
     default:

src/shader_recompiler/backend/spirv/emit_context.h

@@ -215,6 +215,7 @@ public:
     std::array<Id, 30> patches{};
 
     std::array<Id, 8> frag_color{};
+    Id sample_mask{};
     Id frag_depth{};
 
     std::vector<Id> interfaces;

src/shader_recompiler/backend/spirv/emit_spirv.h

@@ -58,6 +58,7 @@ void EmitSetAttributeIndexed(EmitContext& ctx, Id offset, Id value, Id vertex);
 Id EmitGetPatch(EmitContext& ctx, IR::Patch patch);
 void EmitSetPatch(EmitContext& ctx, IR::Patch patch, Id value);
 void EmitSetFragColor(EmitContext& ctx, u32 index, u32 component, Id value);
+void EmitSetSampleMask(EmitContext& ctx, Id value);
 void EmitSetFragDepth(EmitContext& ctx, Id value);
 void EmitGetZFlag(EmitContext& ctx);
 void EmitGetSFlag(EmitContext& ctx);

src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp

@@ -343,6 +343,10 @@ void EmitSetFragColor(EmitContext& ctx, u32 index, u32 component, Id value) {
     ctx.OpStore(pointer, value);
 }
 
+void EmitSetSampleMask(EmitContext& ctx, Id value) {
+    ctx.OpStore(ctx.sample_mask, value);
+}
+
 void EmitSetFragDepth(EmitContext& ctx, Id value) {
     ctx.OpStore(ctx.frag_depth, value);
 }