[shader_recompiler] IPA perspective-inject extended to legacy attrs + generic fixed check made vector-level

src/shader_recompiler/frontend/ir/attribute.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
@@ -240,6 +240,14 @@ constexpr size_t NUM_FIXEDFNCTEXTURE = 10;
     return attribute >= Attribute::Generic0X && attribute <= Attribute::Generic31X;
 }
 
+[[nodiscard]] inline bool IsLegacyAttribute(Attribute attribute) noexcept {
+    return (attribute >= Attribute::ColorFrontDiffuseR &&
+            attribute <= Attribute::ColorBackSpecularA) ||
+           attribute == Attribute::FogCoordinate ||
+           (attribute >= Attribute::FixedFncTexture0S &&
+            attribute <= Attribute::FixedFncTexture9Q);
+}
+
 [[nodiscard]] inline u32 GenericAttributeIndex(Attribute attribute) {
     if (!IsGeneric(attribute))
         throw InvalidArgument("Attribute is not generic {}", attribute);

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

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -163,12 +166,24 @@ void TranslatorVisitor::IPA(u64 insn) {
     const IR::Attribute attribute{ipa.attribute};
     IR::F32 value{is_indexed ? ir.GetAttributeIndexed(X(ipa.index_reg))
                              : ir.GetAttribute(attribute)};
-    if (IR::IsGeneric(attribute)) {
-        const ProgramHeader& sph{env.SPH()};
-        const u32 attr_index{IR::GenericAttributeIndex(attribute)};
-        const u32 element{static_cast<u32>(attribute) % 4};
-        const std::array input_map{sph.ps.GenericInputMap(attr_index)};
-        const bool is_perspective{input_map[element] == Shader::PixelImap::Perspective};
+    const bool is_legacy{IR::IsLegacyAttribute(attribute)};
+    if (IR::IsGeneric(attribute) || is_legacy) {
+        bool is_perspective{is_legacy &&
+                            ipa.interpolation_mode != InterpolationMode::Sc};
+        if (!is_legacy) {
+            const ProgramHeader& sph{env.SPH()};
+            const u32 attr_index{IR::GenericAttributeIndex(attribute)};
+            const std::array input_map{sph.ps.GenericInputMap(attr_index)};
+            Shader::PixelImap effective_imap{Shader::PixelImap::Unused};
+            for (const Shader::PixelImap component : input_map) {
+                if (component != Shader::PixelImap::Unused) {
+                    effective_imap = component;
+                    break;
+                }
+            }
+            is_perspective = effective_imap == Shader::PixelImap::Perspective ||
+                             effective_imap == Shader::PixelImap::Unused;
+        }
         if (is_perspective) {
             const IR::F32 position_w{ir.GetAttribute(IR::Attribute::PositionW)};
             value = ir.FPMul(value, position_w);

src/shader_recompiler/frontend/maxwell/translate_program.cpp

@@ -132,13 +132,7 @@ void AddNVNStorageBuffers(IR::Program& program) {
     }
 }
 
-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);
-}
+using IR::IsLegacyAttribute; //rescoped to attribute.h to make it visible in load_store_attribute.cpp IPA
 
 std::map<IR::Attribute, IR::Attribute> GenerateLegacyToGenericMappings(
     const VaryingState& state, std::queue<IR::Attribute> unused_generics,