4 files changed, 9 insertions, 3 deletions

diff --git a/src/shader_recompiler/backend/glasm/emit_context.h b/src/shader_recompiler/backend/glasm/emit_context.h
index 057d74790..cd4213cb7 100644
--- a/src/shader_recompiler/backend/glasm/emit_context.h
+++ b/src/shader_recompiler/backend/glasm/emit_context.h
@@ -70,6 +70,8 @@ public:
     Stage stage{};
     std::string_view stage_name = "invalid";
     std::string_view attrib_name = "invalid";
+
+    bool uses_y_direction{};
 };
 
 } // namespace Shader::Backend::GLASM
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm.cpp b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
index 4f838b699..2a0524609 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
@@ -439,6 +439,9 @@ std::string EmitGLASM(const Profile& profile, const RuntimeInfo& runtime_info, I
                   "MOV.F FSWZB[2],1;"
                   "MOV.F FSWZB[3],-1;";
     }
+    if (ctx.uses_y_direction) {
+        header += "PARAM y_direction[1]={state.material.front.ambient};";
+    }
     ctx.code.insert(0, header);
     ctx.code += "END";
     return ctx.code;
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h b/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
index c24c7a71d..7b0f75405 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
@@ -71,7 +71,7 @@ void EmitLocalInvocationId(EmitContext& ctx, IR::Inst& inst);
 void EmitInvocationId(EmitContext& ctx, IR::Inst& inst);
 void EmitSampleId(EmitContext& ctx, IR::Inst& inst);
 void EmitIsHelperInvocation(EmitContext& ctx, IR::Inst& inst);
-void EmitYDirection(EmitContext& ctx);
+void EmitYDirection(EmitContext& ctx, IR::Inst& inst);
 void EmitLoadLocal(EmitContext& ctx, IR::Inst& inst, ScalarU32 word_offset);
 void EmitWriteLocal(EmitContext& ctx, ScalarU32 word_offset, ScalarU32 value);
 void EmitUndefU1(EmitContext& ctx, IR::Inst& inst);
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp b/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp
index 022b6584c..2a92d9df5 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp
@@ -207,8 +207,9 @@ void EmitIsHelperInvocation(EmitContext& ctx, IR::Inst& inst) {
     ctx.Add("MOV.S {}.x,fragment.helperthread.x;", inst);
 }
 
-void EmitYDirection(EmitContext& ctx) {
-    NotImplemented();
+void EmitYDirection(EmitContext& ctx, IR::Inst& inst) {
+    ctx.uses_y_direction = true;
+    ctx.Add("MOV.F {}.x,y_direction[0].w;", inst);
 }
 
 void EmitUndefU1(EmitContext& ctx, IR::Inst& inst) {