shader: Implement PIXLD.MY_INDEX

src/shader_recompiler/backend/spirv/emit_context.cpp

@@ -998,6 +998,9 @@ void EmitContext::DefineInputs(const Info& info) {
     if (info.uses_invocation_id) {
         invocation_id = DefineInput(*this, U32[1], false, spv::BuiltIn::InvocationId);
     }
+    if (info.uses_sample_id) {
+        sample_id = DefineInput(*this, U32[1], false, spv::BuiltIn::SampleId);
+    }
     if (info.uses_is_helper_invocation) {
         is_helper_invocation = DefineInput(*this, U1, false, spv::BuiltIn::HelperInvocation);
     }

src/shader_recompiler/backend/spirv/emit_context.h

@@ -149,6 +149,7 @@ public:
     Id workgroup_id{};
     Id local_invocation_id{};
     Id invocation_id{};
+    Id sample_id{};
     Id is_helper_invocation{};
     Id subgroup_local_invocation_id{};
     Id subgroup_mask_eq{};

src/shader_recompiler/backend/spirv/emit_spirv.cpp

@@ -335,6 +335,9 @@ void SetupCapabilities(const Profile& profile, const Info& info, EmitContext& ct
     if (info.uses_typeless_image_writes) {
         ctx.AddCapability(spv::Capability::StorageImageWriteWithoutFormat);
     }
+    if (info.uses_sample_id) {
+        ctx.AddCapability(spv::Capability::SampleRateShading);
+    }
     if (!ctx.profile.xfb_varyings.empty()) {
         ctx.AddCapability(spv::Capability::TransformFeedback);
     }

src/shader_recompiler/backend/spirv/emit_spirv.h

@@ -70,6 +70,7 @@ void EmitSetOFlag(EmitContext& ctx);
 Id EmitWorkgroupId(EmitContext& ctx);
 Id EmitLocalInvocationId(EmitContext& ctx);
 Id EmitInvocationId(EmitContext& ctx);
+Id EmitSampleId(EmitContext& ctx);
 Id EmitIsHelperInvocation(EmitContext& ctx);
 Id EmitLoadLocal(EmitContext& ctx, Id word_offset);
 void EmitWriteLocal(EmitContext& ctx, Id word_offset, Id value);

src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp

@@ -391,6 +391,10 @@ Id EmitInvocationId(EmitContext& ctx) {
     return ctx.OpLoad(ctx.U32[1], ctx.invocation_id);
 }
 
+Id EmitSampleId(EmitContext& ctx) {
+    return ctx.OpLoad(ctx.U32[1], ctx.sample_id);
+}
+
 Id EmitIsHelperInvocation(EmitContext& ctx) {
     return ctx.OpLoad(ctx.U1, ctx.is_helper_invocation);
 }