shader: Implement SR_Y_DIRECTION

src/shader_recompiler/backend/spirv/emit_spirv.h

@@ -72,6 +72,7 @@ Id EmitLocalInvocationId(EmitContext& ctx);
 Id EmitInvocationId(EmitContext& ctx);
 Id EmitSampleId(EmitContext& ctx);
 Id EmitIsHelperInvocation(EmitContext& ctx);
+Id EmitYDirection(EmitContext& ctx);
 Id EmitLoadLocal(EmitContext& ctx, Id word_offset);
 void EmitWriteLocal(EmitContext& ctx, Id word_offset, Id value);
 Id EmitUndefU1(EmitContext& ctx);

src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp

@@ -403,6 +403,13 @@ Id EmitIsHelperInvocation(EmitContext& ctx) {
     return ctx.OpLoad(ctx.U1, ctx.is_helper_invocation);
 }
 
+Id EmitYDirection(EmitContext& ctx) {
+    if (ctx.profile.y_negate) {
+        return ctx.Constant(ctx.F32[1], -1.0f);
+    }
+    return ctx.Constant(ctx.F32[1], 1.0f);
+}
+
 Id EmitLoadLocal(EmitContext& ctx, Id word_offset) {
     const Id pointer{ctx.OpAccessChain(ctx.private_u32, ctx.local_memory, word_offset)};
     return ctx.OpLoad(ctx.U32[1], pointer);

src/shader_recompiler/frontend/ir/ir_emitter.cpp

@@ -379,6 +379,10 @@ U1 IREmitter::IsHelperInvocation() {
     return Inst<U1>(Opcode::IsHelperInvocation);
 }
 
+F32 IREmitter::YDirection() {
+    return Inst<F32>(Opcode::YDirection);
+}
+
 U32 IREmitter::LaneId() {
     return Inst<U32>(Opcode::LaneId);
 }

src/shader_recompiler/frontend/ir/ir_emitter.h

@@ -102,6 +102,7 @@ public:
     [[nodiscard]] U32 InvocationId();
     [[nodiscard]] U32 SampleId();
     [[nodiscard]] U1 IsHelperInvocation();
+    [[nodiscard]] F32 YDirection();
 
     [[nodiscard]] U32 LaneId();
 

src/shader_recompiler/frontend/ir/opcodes.inc

@@ -65,6 +65,7 @@ OPCODE(LocalInvocationId,                                   U32x3,
 OPCODE(InvocationId,                                        U32,                                                                                            )
 OPCODE(SampleId,                                            U32,                                                                                            )
 OPCODE(IsHelperInvocation,                                  U1,                                                                                             )
+OPCODE(YDirection,                                          F32,                                                                                            )
 
 // Undefined
 OPCODE(UndefU1,                                             U1,                                                                                             )

src/shader_recompiler/frontend/maxwell/translate/impl/move_special_register.cpp

@@ -150,6 +150,8 @@ enum class SpecialRegister : u64 {
         return ir.SubgroupGtMask();
     case SpecialRegister::SR_GEMASK:
         return ir.SubgroupGeMask();
+    case SpecialRegister::SR_Y_DIRECTION:
+        return ir.BitCast<IR::U32>(ir.YDirection());
     default:
         throw NotImplementedException("S2R special register {}", special_register);
     }

src/shader_recompiler/profile.h

@@ -97,6 +97,8 @@ struct Profile {
     std::optional<CompareFunction> alpha_test_func;
     float alpha_test_reference{};
 
+    bool y_negate{};
+
     std::vector<TransformFeedbackVarying> xfb_varyings;
 };