shader: Implement PrimitiveId

3 files changed, 6 insertions, 0 deletions

diff --git a/src/shader_recompiler/backend/spirv/emit_context.cpp b/src/shader_recompiler/backend/spirv/emit_context.cpp
index 067f61613..3946dab14 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_context.cpp
@@ -1021,6 +1021,9 @@ void EmitContext::DefineInputs(const Info& info) {
         fswzadd_lut_b =
             ConstantComposite(F32[4], f32_minus_one, f32_minus_one, f32_one, f32_minus_one);
     }
+    if (info.loads_primitive_id) {
+        primitive_id = DefineInput(*this, U32[1], false, spv::BuiltIn::PrimitiveId);
+    }
     if (info.loads_position) {
         const bool is_fragment{stage != Stage::Fragment};
         const spv::BuiltIn built_in{is_fragment ? spv::BuiltIn::Position : spv::BuiltIn::FragCoord};
diff --git a/src/shader_recompiler/backend/spirv/emit_context.h b/src/shader_recompiler/backend/spirv/emit_context.h
index ba0a253b3..c7d6f8a38 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.h
+++ b/src/shader_recompiler/backend/spirv/emit_context.h
@@ -167,6 +167,7 @@ public:
     Id clip_distances{};
     Id layer{};
     Id viewport_index{};
+    Id primitive_id{};
 
     Id fswzadd_lut_a{};
     Id fswzadd_lut_b{};
diff --git a/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp b/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
index 4a1aeece5..23a74f966 100644
--- a/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp
@@ -210,6 +210,8 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
         return type->needs_cast ? ctx.OpBitcast(ctx.F32[1], value) : value;
     }
     switch (attr) {
+    case IR::Attribute::PrimitiveId:
+        return ctx.OpLoad(ctx.U32[1], ctx.primitive_id);
     case IR::Attribute::PositionX:
     case IR::Attribute::PositionY:
     case IR::Attribute::PositionZ: