shader: Initial OpenGL implementation

src/shader_recompiler/frontend/ir/ir_emitter.cpp

@@ -355,6 +355,10 @@ U32 IREmitter::WorkgroupIdZ() {
     return U32{CompositeExtract(Inst(Opcode::WorkgroupId), 2)};
 }
 
+Value IREmitter::LocalInvocationId() {
+    return Inst(Opcode::LocalInvocationId);
+}
+
 U32 IREmitter::LocalInvocationIdX() {
     return U32{CompositeExtract(Inst(Opcode::LocalInvocationId), 0)};
 }

src/shader_recompiler/frontend/ir/ir_emitter.h

@@ -95,6 +95,7 @@ public:
     [[nodiscard]] U32 WorkgroupIdY();
     [[nodiscard]] U32 WorkgroupIdZ();
 
+    [[nodiscard]] Value LocalInvocationId();
     [[nodiscard]] U32 LocalInvocationIdX();
     [[nodiscard]] U32 LocalInvocationIdY();
     [[nodiscard]] U32 LocalInvocationIdZ();