3 files changed, 153 insertions, 71 deletions

diff --git a/src/shader_recompiler/backend/spirv/emit_context.cpp b/src/shader_recompiler/backend/spirv/emit_context.cpp
index 2885e6799..3c84e6466 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_context.cpp
@@ -430,15 +430,33 @@ Id DescType(EmitContext& ctx, Id sampled_type, Id pointer_type, u32 count) {
     }
 }
 
-size_t FindNextUnusedLocation(const std::bitset<IR::NUM_GENERICS>& used_locations,
-                              size_t start_offset) {
+size_t FindAndSetNextUnusedLocation(std::bitset<IR::NUM_GENERICS>& used_locations,
+                                    size_t& start_offset) {
     for (size_t location = start_offset; location < used_locations.size(); ++location) {
         if (!used_locations.test(location)) {
+            start_offset = location;
+            used_locations.set(location);
             return location;
         }
     }
     throw RuntimeError("Unable to get an unused location for legacy attribute");
 }
+
+Id DefineLegacyInput(EmitContext& ctx, std::bitset<IR::NUM_GENERICS>& used_locations,
+                     size_t& start_offset) {
+    const Id id{DefineInput(ctx, ctx.F32[4], true)};
+    const size_t location = FindAndSetNextUnusedLocation(used_locations, start_offset);
+    ctx.Decorate(id, spv::Decoration::Location, location);
+    return id;
+}
+
+Id DefineLegacyOutput(EmitContext& ctx, std::bitset<IR::NUM_GENERICS>& used_locations,
+                      size_t& start_offset, std::optional<u32> invocations) {
+    const Id id{DefineOutput(ctx, ctx.F32[4], invocations)};
+    const size_t location = FindAndSetNextUnusedLocation(used_locations, start_offset);
+    ctx.Decorate(id, spv::Decoration::Location, location);
+    return id;
+}
 } // Anonymous namespace
 
 void VectorTypes::Define(Sirit::Module& sirit_ctx, Id base_type, std::string_view name) {
@@ -520,6 +538,64 @@ Id EmitContext::BitOffset16(const IR::Value& offset) {
     return OpBitwiseAnd(U32[1], OpShiftLeftLogical(U32[1], Def(offset), Const(3u)), Const(16u));
 }
 
+Id EmitContext::InputLegacyAttribute(IR::Attribute attribute) {
+    if (attribute >= IR::Attribute::ColorFrontDiffuseR &&
+        attribute <= IR::Attribute::ColorFrontDiffuseA) {
+        return input_front_color;
+    }
+    if (attribute >= IR::Attribute::ColorFrontSpecularR &&
+        attribute <= IR::Attribute::ColorFrontSpecularA) {
+        return input_front_secondary_color;
+    }
+    if (attribute >= IR::Attribute::ColorBackDiffuseR &&
+        attribute <= IR::Attribute::ColorBackDiffuseA) {
+        return input_back_color;
+    }
+    if (attribute >= IR::Attribute::ColorBackSpecularR &&
+        attribute <= IR::Attribute::ColorBackSpecularA) {
+        return input_back_secondary_color;
+    }
+    if (attribute == IR::Attribute::FogCoordinate) {
+        return input_fog_frag_coord;
+    }
+    if (attribute >= IR::Attribute::FixedFncTexture0S &&
+        attribute <= IR::Attribute::FixedFncTexture9Q) {
+        u32 index =
+            (static_cast<u32>(attribute) - static_cast<u32>(IR::Attribute::FixedFncTexture0S)) / 4;
+        return input_fixed_fnc_textures[index];
+    }
+    throw InvalidArgument("Attribute is not legacy attribute {}", attribute);
+}
+
+Id EmitContext::OutputLegacyAttribute(IR::Attribute attribute) {
+    if (attribute >= IR::Attribute::ColorFrontDiffuseR &&
+        attribute <= IR::Attribute::ColorFrontDiffuseA) {
+        return output_front_color;
+    }
+    if (attribute >= IR::Attribute::ColorFrontSpecularR &&
+        attribute <= IR::Attribute::ColorFrontSpecularA) {
+        return output_front_secondary_color;
+    }
+    if (attribute >= IR::Attribute::ColorBackDiffuseR &&
+        attribute <= IR::Attribute::ColorBackDiffuseA) {
+        return output_back_color;
+    }
+    if (attribute >= IR::Attribute::ColorBackSpecularR &&
+        attribute <= IR::Attribute::ColorBackSpecularA) {
+        return output_back_secondary_color;
+    }
+    if (attribute == IR::Attribute::FogCoordinate) {
+        return output_fog_frag_coord;
+    }
+    if (attribute >= IR::Attribute::FixedFncTexture0S &&
+        attribute <= IR::Attribute::FixedFncTexture9Q) {
+        u32 index =
+            (static_cast<u32>(attribute) - static_cast<u32>(IR::Attribute::FixedFncTexture0S)) / 4;
+        return output_fixed_fnc_textures[index];
+    }
+    throw InvalidArgument("Attribute is not legacy attribute {}", attribute);
+}
+
 void EmitContext::DefineCommonTypes(const Info& info) {
     void_id = TypeVoid();
 
@@ -1279,22 +1355,26 @@ void EmitContext::DefineInputs(const IR::Program& program) {
     }
     size_t previous_unused_location = 0;
     if (loads.AnyComponent(IR::Attribute::ColorFrontDiffuseR)) {
-        const size_t location = FindNextUnusedLocation(used_locations, previous_unused_location);
-        previous_unused_location = location;
-        used_locations.set(location);
-        const Id id{DefineInput(*this, F32[4], true)};
-        Decorate(id, spv::Decoration::Location, location);
-        input_front_color = id;
+        input_front_color = DefineLegacyInput(*this, used_locations, previous_unused_location);
+    }
+    if (loads.AnyComponent(IR::Attribute::ColorFrontSpecularR)) {
+        input_front_secondary_color =
+            DefineLegacyInput(*this, used_locations, previous_unused_location);
+    }
+    if (loads.AnyComponent(IR::Attribute::ColorBackDiffuseR)) {
+        input_back_color = DefineLegacyInput(*this, used_locations, previous_unused_location);
+    }
+    if (loads.AnyComponent(IR::Attribute::ColorBackSpecularR)) {
+        input_back_secondary_color =
+            DefineLegacyInput(*this, used_locations, previous_unused_location);
+    }
+    if (loads.AnyComponent(IR::Attribute::FogCoordinate)) {
+        input_fog_frag_coord = DefineLegacyInput(*this, used_locations, previous_unused_location);
     }
     for (size_t index = 0; index < NUM_FIXEDFNCTEXTURE; ++index) {
         if (loads.AnyComponent(IR::Attribute::FixedFncTexture0S + index * 4)) {
-            const size_t location =
-                FindNextUnusedLocation(used_locations, previous_unused_location);
-            previous_unused_location = location;
-            used_locations.set(location);
-            const Id id{DefineInput(*this, F32[4], true)};
-            Decorate(id, spv::Decoration::Location, location);
-            input_fixed_fnc_textures[index] = id;
+            input_fixed_fnc_textures[index] =
+                DefineLegacyInput(*this, used_locations, previous_unused_location);
         }
     }
     if (stage == Stage::TessellationEval) {
@@ -1356,22 +1436,29 @@ void EmitContext::DefineOutputs(const IR::Program& program) {
     }
     size_t previous_unused_location = 0;
     if (info.stores.AnyComponent(IR::Attribute::ColorFrontDiffuseR)) {
-        const size_t location = FindNextUnusedLocation(used_locations, previous_unused_location);
-        previous_unused_location = location;
-        used_locations.set(location);
-        const Id id{DefineOutput(*this, F32[4], invocations)};
-        Decorate(id, spv::Decoration::Location, static_cast<u32>(location));
-        output_front_color = id;
+        output_front_color =
+            DefineLegacyOutput(*this, used_locations, previous_unused_location, invocations);
+    }
+    if (info.stores.AnyComponent(IR::Attribute::ColorFrontSpecularR)) {
+        output_front_secondary_color =
+            DefineLegacyOutput(*this, used_locations, previous_unused_location, invocations);
+    }
+    if (info.stores.AnyComponent(IR::Attribute::ColorBackDiffuseR)) {
+        output_back_color =
+            DefineLegacyOutput(*this, used_locations, previous_unused_location, invocations);
+    }
+    if (info.stores.AnyComponent(IR::Attribute::ColorBackSpecularR)) {
+        output_back_secondary_color =
+            DefineLegacyOutput(*this, used_locations, previous_unused_location, invocations);
+    }
+    if (info.stores.AnyComponent(IR::Attribute::FogCoordinate)) {
+        output_fog_frag_coord =
+            DefineLegacyOutput(*this, used_locations, previous_unused_location, invocations);
     }
     for (size_t index = 0; index < NUM_FIXEDFNCTEXTURE; ++index) {
         if (info.stores.AnyComponent(IR::Attribute::FixedFncTexture0S + index * 4)) {
-            const size_t location =
-                FindNextUnusedLocation(used_locations, previous_unused_location);
-            previous_unused_location = location;
-            used_locations.set(location);
-            const Id id{DefineOutput(*this, F32[4], invocations)};
-            Decorate(id, spv::Decoration::Location, location);
-            output_fixed_fnc_textures[index] = id;
+            output_fixed_fnc_textures[index] =
+                DefineLegacyOutput(*this, used_locations, previous_unused_location, invocations);
         }
     }
     switch (stage) {
diff --git a/src/shader_recompiler/backend/spirv/emit_context.h b/src/shader_recompiler/backend/spirv/emit_context.h
index 847d0c0e6..112c52382 100644
--- a/src/shader_recompiler/backend/spirv/emit_context.h
+++ b/src/shader_recompiler/backend/spirv/emit_context.h
@@ -113,6 +113,9 @@ public:
     [[nodiscard]] Id BitOffset8(const IR::Value& offset);
     [[nodiscard]] Id BitOffset16(const IR::Value& offset);
 
+    Id InputLegacyAttribute(IR::Attribute attribute);
+    Id OutputLegacyAttribute(IR::Attribute attribute);
+
     Id Const(u32 value) {
         return Constant(U32[1], value);
     }
@@ -269,12 +272,20 @@ public:
 
     Id input_position{};
     Id input_front_color{};
+    Id input_front_secondary_color{};
+    Id input_back_color{};
+    Id input_back_secondary_color{};
+    Id input_fog_frag_coord{};
     std::array<Id, 10> input_fixed_fnc_textures{};
     std::array<Id, 32> input_generics{};
 
     Id output_point_size{};
     Id output_position{};
     Id output_front_color{};
+    Id output_front_secondary_color{};
+    Id output_back_color{};
+    Id output_back_secondary_color{};
+    Id output_fog_frag_coord{};
     std::array<Id, 10> output_fixed_fnc_textures{};
     std::array<std::array<GenericElementInfo, 4>, 32> output_generics{};
 
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 6f60c6574..d3a93d5f4 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
@@ -43,23 +43,12 @@ Id AttrPointer(EmitContext& ctx, Id pointer_type, Id vertex, Id base, Args&&...
     }
 }
 
-bool IsFixedFncTexture(IR::Attribute attribute) {
-    return attribute >= IR::Attribute::FixedFncTexture0S &&
-           attribute <= IR::Attribute::FixedFncTexture9Q;
-}
-
-u32 FixedFncTextureAttributeIndex(IR::Attribute attribute) {
-    if (!IsFixedFncTexture(attribute)) {
-        throw InvalidArgument("Attribute {} is not a FixedFncTexture", attribute);
-    }
-    return (static_cast<u32>(attribute) - static_cast<u32>(IR::Attribute::FixedFncTexture0S)) / 4u;
-}
-
-u32 FixedFncTextureAttributeElement(IR::Attribute attribute) {
-    if (!IsFixedFncTexture(attribute)) {
-        throw InvalidArgument("Attribute {} is not a FixedFncTexture", attribute);
-    }
-    return static_cast<u32>(attribute) % 4u;
+bool IsLegacyAttribute(IR::Attribute attribute) {
+    return (attribute >= IR::Attribute::ColorFrontDiffuseR &&
+            attribute <= IR::Attribute::ColorBackSpecularA) ||
+           attribute == IR::Attribute::FogCoordinate ||
+           (attribute >= IR::Attribute::FixedFncTexture0S &&
+            attribute <= IR::Attribute::FixedFncTexture9Q);
 }
 
 template <typename... Args>
@@ -93,12 +82,16 @@ std::optional<OutAttr> OutputAttrPointer(EmitContext& ctx, IR::Attribute attr) {
             return OutputAccessChain(ctx, ctx.output_f32, info.id, index_id);
         }
     }
-    if (IsFixedFncTexture(attr)) {
-        const u32 index{FixedFncTextureAttributeIndex(attr)};
-        const u32 element{FixedFncTextureAttributeElement(attr)};
-        const Id element_id{ctx.Const(element)};
-        return OutputAccessChain(ctx, ctx.output_f32, ctx.output_fixed_fnc_textures[index],
-                                 element_id);
+    if (IsLegacyAttribute(attr)) {
+        if (attr == IR::Attribute::FogCoordinate) {
+            return OutputAccessChain(ctx, ctx.output_f32, ctx.OutputLegacyAttribute(attr),
+                                     ctx.Const(0u));
+        } else {
+            const u32 element{static_cast<u32>(attr) % 4};
+            const Id element_id{ctx.Const(element)};
+            return OutputAccessChain(ctx, ctx.output_f32, ctx.OutputLegacyAttribute(attr),
+                                     element_id);
+        }
     }
     switch (attr) {
     case IR::Attribute::PointSize:
@@ -111,14 +104,6 @@ std::optional<OutAttr> OutputAttrPointer(EmitContext& ctx, IR::Attribute attr) {
         const Id element_id{ctx.Const(element)};
         return OutputAccessChain(ctx, ctx.output_f32, ctx.output_position, element_id);
     }
-    case IR::Attribute::ColorFrontDiffuseR:
-    case IR::Attribute::ColorFrontDiffuseG:
-    case IR::Attribute::ColorFrontDiffuseB:
-    case IR::Attribute::ColorFrontDiffuseA: {
-        const u32 element{static_cast<u32>(attr) % 4};
-        const Id element_id{ctx.Const(element)};
-        return OutputAccessChain(ctx, ctx.output_f32, ctx.output_front_color, element_id);
-    }
     case IR::Attribute::ClipDistance0:
     case IR::Attribute::ClipDistance1:
     case IR::Attribute::ClipDistance2:
@@ -341,11 +326,17 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
         const Id value{ctx.OpLoad(type->id, pointer)};
         return type->needs_cast ? ctx.OpBitcast(ctx.F32[1], value) : value;
     }
-    if (IsFixedFncTexture(attr)) {
-        const u32 index{FixedFncTextureAttributeIndex(attr)};
-        const Id attr_id{ctx.input_fixed_fnc_textures[index]};
-        const Id attr_ptr{AttrPointer(ctx, ctx.input_f32, vertex, attr_id, ctx.Const(element))};
-        return ctx.OpLoad(ctx.F32[1], attr_ptr);
+    if (IsLegacyAttribute(attr)) {
+        if (attr == IR::Attribute::FogCoordinate) {
+            const Id attr_ptr{AttrPointer(ctx, ctx.input_f32, vertex,
+                                          ctx.InputLegacyAttribute(attr), ctx.Const(0u))};
+            return ctx.OpLoad(ctx.F32[1], attr_ptr);
+        } else {
+            const Id element_id{ctx.Const(element)};
+            const Id attr_ptr{AttrPointer(ctx, ctx.input_f32, vertex,
+                                          ctx.InputLegacyAttribute(attr), element_id)};
+            return ctx.OpLoad(ctx.F32[1], attr_ptr);
+        }
     }
     switch (attr) {
     case IR::Attribute::PrimitiveId:
@@ -356,13 +347,6 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
     case IR::Attribute::PositionW:
         return ctx.OpLoad(ctx.F32[1], AttrPointer(ctx, ctx.input_f32, vertex, ctx.input_position,
                                                   ctx.Const(element)));
-    case IR::Attribute::ColorFrontDiffuseR:
-    case IR::Attribute::ColorFrontDiffuseG:
-    case IR::Attribute::ColorFrontDiffuseB:
-    case IR::Attribute::ColorFrontDiffuseA: {
-        return ctx.OpLoad(ctx.F32[1], AttrPointer(ctx, ctx.input_f32, vertex, ctx.input_front_color,
-                                                  ctx.Const(element)));
-    }
     case IR::Attribute::InstanceId:
         if (ctx.profile.support_vertex_instance_id) {
             return ctx.OpBitcast(ctx.F32[1], ctx.OpLoad(ctx.U32[1], ctx.instance_id));