1 files changed, 39 insertions, 22 deletions

diff --git a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
index e9f8d40db..29de5c9db 100644
--- a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp
@@ -45,7 +45,6 @@ struct TextureAoffi {};
 using TextureArgument = std::pair<Type, Node>;
 using TextureIR = std::variant<TextureAoffi, TextureArgument>;
 
-enum : u32 { POSITION_VARYING_LOCATION = 0, GENERIC_VARYING_START_LOCATION = 1 };
 constexpr u32 MAX_CONSTBUFFER_ELEMENTS =
     static_cast<u32>(RasterizerOpenGL::MaxConstbufferSize) / (4 * sizeof(float));
 
@@ -247,6 +246,12 @@ private:
         code.AddLine("layout ({}, max_vertices = {}) out;", topology, max_vertices);
         code.AddNewLine();
 
+        code.AddLine("in gl_PerVertex {{");
+        ++code.scope;
+        code.AddLine("vec4 gl_Position;");
+        --code.scope;
+        code.AddLine("}} gl_in[];");
+
         DeclareVertexRedeclarations();
     }
 
@@ -349,7 +354,7 @@ private:
     }
 
     void DeclareInputAttribute(Attribute::Index index, bool skip_unused) {
-        const u32 generic_index{GetGenericAttributeIndex(index)};
+        const u32 location{GetGenericAttributeIndex(index)};
 
         std::string name{GetInputAttribute(index)};
         if (stage == ShaderStage::Geometry) {
@@ -358,19 +363,13 @@ private:
 
         std::string suffix;
         if (stage == ShaderStage::Fragment) {
-            const auto input_mode{header.ps.GetAttributeUse(generic_index)};
+            const auto input_mode{header.ps.GetAttributeUse(location)};
             if (skip_unused && input_mode == AttributeUse::Unused) {
                 return;
             }
             suffix = GetInputFlags(input_mode);
         }
 
-        u32 location = generic_index;
-        if (stage != ShaderStage::Vertex) {
-            // If inputs are varyings, add an offset
-            location += GENERIC_VARYING_START_LOCATION;
-        }
-
         code.AddLine("layout (location = {}) {} in vec4 {};", location, suffix, name);
     }
 
@@ -395,7 +394,7 @@ private:
     }
 
     void DeclareOutputAttribute(Attribute::Index index) {
-        const u32 location{GetGenericAttributeIndex(index) + GENERIC_VARYING_START_LOCATION};
+        const u32 location{GetGenericAttributeIndex(index)};
         code.AddLine("layout (location = {}) out vec4 {};", location, GetOutputAttribute(index));
     }
 
@@ -577,9 +576,26 @@ private:
             if (std::holds_alternative<OperationNode>(*offset)) {
                 // Indirect access
                 const std::string final_offset = code.GenerateTemporary();
-                code.AddLine("uint {} = (ftou({}) / 4);", final_offset, Visit(offset));
-                return fmt::format("{}[{} / 4][{} % 4]", GetConstBuffer(cbuf->GetIndex()),
-                                   final_offset, final_offset);
+                code.AddLine("uint {} = ftou({}) >> 2;", final_offset, Visit(offset));
+
+                if (!device.HasComponentIndexingBug()) {
+                    return fmt::format("{}[{} >> 2][{} & 3]", GetConstBuffer(cbuf->GetIndex()),
+                                       final_offset, final_offset);
+                }
+
+                // AMD's proprietary GLSL compiler emits ill code for variable component access.
+                // To bypass this driver bug generate 4 ifs, one per each component.
+                const std::string pack = code.GenerateTemporary();
+                code.AddLine("vec4 {} = {}[{} >> 2];", pack, GetConstBuffer(cbuf->GetIndex()),
+                             final_offset);
+
+                const std::string result = code.GenerateTemporary();
+                code.AddLine("float {};", result);
+                for (u32 swizzle = 0; swizzle < 4; ++swizzle) {
+                    code.AddLine("if (({} & 3) == {}) {} = {}{};", final_offset, swizzle, result,
+                                 pack, GetSwizzle(swizzle));
+                }
+                return result;
             }
 
             UNREACHABLE_MSG("Unmanaged offset node type");
@@ -633,10 +649,14 @@ private:
 
         switch (attribute) {
         case Attribute::Index::Position:
-            if (stage != ShaderStage::Fragment) {
-                return GeometryPass("position") + GetSwizzle(element);
-            } else {
+            switch (stage) {
+            case ShaderStage::Geometry:
+                return fmt::format("gl_in[ftou({})].gl_Position{}", Visit(buffer),
+                                   GetSwizzle(element));
+            case ShaderStage::Fragment:
                 return element == 3 ? "1.0f" : ("gl_FragCoord"s + GetSwizzle(element));
+            default:
+                UNREACHABLE();
             }
         case Attribute::Index::PointCoord:
             switch (element) {
@@ -921,7 +941,7 @@ private:
             target = [&]() -> std::string {
                 switch (const auto attribute = abuf->GetIndex(); abuf->GetIndex()) {
                 case Attribute::Index::Position:
-                    return "position"s + GetSwizzle(abuf->GetElement());
+                    return "gl_Position"s + GetSwizzle(abuf->GetElement());
                 case Attribute::Index::PointSize:
                     return "gl_PointSize";
                 case Attribute::Index::ClipDistances0123:
@@ -1506,9 +1526,7 @@ private:
 
         // If a geometry shader is attached, it will always flip (it's the last stage before
         // fragment). For more info about flipping, refer to gl_shader_gen.cpp.
-        code.AddLine("position.xy *= viewport_flip.xy;");
-        code.AddLine("gl_Position = position;");
-        code.AddLine("position.w = 1.0;");
+        code.AddLine("gl_Position.xy *= viewport_flip.xy;");
         code.AddLine("EmitVertex();");
         return {};
     }
@@ -1746,8 +1764,7 @@ private:
     }
 
     u32 GetNumPhysicalVaryings() const {
-        return std::min<u32>(device.GetMaxVaryings() - GENERIC_VARYING_START_LOCATION,
-                             Maxwell::NumVaryings);
+        return std::min<u32>(device.GetMaxVaryings(), Maxwell::NumVaryings);
     }
 
     const Device& device;