Support gl_FogFragCoord attribute

src/shader_recompiler/backend/spirv/emit_context.cpp

@@ -430,10 +430,12 @@ 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;
         }
     }
@@ -1279,45 +1281,40 @@ 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);
+        Decorate(id, spv::Decoration::Location,
+                 FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
         input_front_color = id;
     }
     if (loads.AnyComponent(IR::Attribute::ColorFrontSpecularR)) {
-        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);
+        Decorate(id, spv::Decoration::Location,
+                 FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
         input_front_secondary_color = id;
     }
     if (loads.AnyComponent(IR::Attribute::ColorBackDiffuseR)) {
-        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);
+        Decorate(id, spv::Decoration::Location,
+                 FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
         input_back_color = id;
     }
     if (loads.AnyComponent(IR::Attribute::ColorBackSpecularR)) {
-        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);
+        Decorate(id, spv::Decoration::Location,
+                 FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
         input_back_secondary_color = id;
     }
+    if (loads.AnyComponent(IR::Attribute::FogCoordinate)) {
+        const Id id{DefineInput(*this, F32[4], true)};
+        Decorate(id, spv::Decoration::Location,
+                 FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
+        input_fog_frag_coord = id;
+    }
     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);
+            Decorate(id, spv::Decoration::Location,
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
             input_fixed_fnc_textures[index] = id;
         }
     }
@@ -1380,45 +1377,45 @@ 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));
+        Decorate(id, spv::Decoration::Location,
+                 static_cast<u32>(
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location)));
         output_front_color = id;
     }
     if (info.stores.AnyComponent(IR::Attribute::ColorFrontSpecularR)) {
-        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));
+        Decorate(id, spv::Decoration::Location,
+                 static_cast<u32>(
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location)));
         output_front_secondary_color = id;
     }
     if (info.stores.AnyComponent(IR::Attribute::ColorBackDiffuseR)) {
-        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));
+        Decorate(id, spv::Decoration::Location,
+                 static_cast<u32>(
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location)));
         output_back_color = id;
     }
     if (info.stores.AnyComponent(IR::Attribute::ColorBackSpecularR)) {
-        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));
+        Decorate(id, spv::Decoration::Location,
+                 static_cast<u32>(
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location)));
         output_back_secondary_color = id;
     }
+    if (info.stores.AnyComponent(IR::Attribute::FogCoordinate)) {
+        const Id id{DefineOutput(*this, F32[4], invocations)};
+        Decorate(id, spv::Decoration::Location,
+                 static_cast<u32>(
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location)));
+        output_fog_frag_coord = id;
+    }
     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);
+            Decorate(id, spv::Decoration::Location,
+                     FindAndSetNextUnusedLocation(used_locations, previous_unused_location));
             output_fixed_fnc_textures[index] = id;
         }
     }

src/shader_recompiler/backend/spirv/emit_context.h

@@ -272,6 +272,7 @@ public:
     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{};
 
@@ -281,6 +282,7 @@ public:
     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{};
 

src/shader_recompiler/backend/spirv/emit_spirv_context_get_set.cpp

@@ -143,6 +143,11 @@ std::optional<OutAttr> OutputAttrPointer(EmitContext& ctx, IR::Attribute attr) {
         const Id element_id{ctx.Const(element)};
         return OutputAccessChain(ctx, ctx.output_f32, ctx.output_back_secondary_color, element_id);
     }
+    case IR::Attribute::FogCoordinate: {
+        const u32 element{static_cast<u32>(attr) % 4};
+        const Id element_id{ctx.Const(element)};
+        return OutputAccessChain(ctx, ctx.output_f32, ctx.output_fog_frag_coord, element_id);
+    }
     case IR::Attribute::ClipDistance0:
     case IR::Attribute::ClipDistance1:
     case IR::Attribute::ClipDistance2:
@@ -391,8 +396,9 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
     case IR::Attribute::ColorFrontSpecularG:
     case IR::Attribute::ColorFrontSpecularB:
     case IR::Attribute::ColorFrontSpecularA: {
-        return ctx.OpLoad(ctx.F32[1], AttrPointer(ctx, ctx.input_f32, vertex, ctx.input_front_secondary_color,
-                                                  ctx.Const(element)));
+        return ctx.OpLoad(ctx.F32[1],
+                          AttrPointer(ctx, ctx.input_f32, vertex, ctx.input_front_secondary_color,
+                                      ctx.Const(element)));
     }
     case IR::Attribute::ColorBackDiffuseR:
     case IR::Attribute::ColorBackDiffuseG:
@@ -405,8 +411,13 @@ Id EmitGetAttribute(EmitContext& ctx, IR::Attribute attr, Id vertex) {
     case IR::Attribute::ColorBackSpecularG:
     case IR::Attribute::ColorBackSpecularB:
     case IR::Attribute::ColorBackSpecularA: {
-        return ctx.OpLoad(ctx.F32[1], AttrPointer(ctx, ctx.input_f32, vertex, ctx.input_back_secondary_color,
-                                                  ctx.Const(element)));
+        return ctx.OpLoad(ctx.F32[1],
+                          AttrPointer(ctx, ctx.input_f32, vertex, ctx.input_back_secondary_color,
+                                      ctx.Const(element)));
+    }
+    case IR::Attribute::FogCoordinate: {
+        return ctx.OpLoad(ctx.F32[1], AttrPointer(ctx, ctx.input_f32, vertex,
+                                                  ctx.input_fog_frag_coord, ctx.Const(element)));
     }
     case IR::Attribute::InstanceId:
         if (ctx.profile.support_vertex_instance_id) {