Make sure attributes used on subsequent shader stages are initialized (#2538)

2 files changed, 15 insertions, 88 deletions

diff --git a/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs b/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs
index 478ae497..2a93be32 100644
--- a/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs
+++ b/Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs
@@ -3,14 +3,12 @@ using Ryujinx.Graphics.Shader.StructuredIr;
 using Ryujinx.Graphics.Shader.Translation;
 using System;
 using System.Linq;
+using System.Numerics;
 
 namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
 {
     static class Declarations
     {
-        // At least 16 attributes are guaranteed by the spec.
-        public const int MaxAttributes = 16;
-
         public static void Declare(CodeGenContext context, StructuredProgramInfo info)
         {
             context.AppendLine("#version 450 core");
@@ -129,14 +127,14 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
                     context.AppendLine();
                 }
 
-                if (info.IAttributes.Count != 0 || context.Config.GpPassthrough)
+                if (context.Config.UsedInputAttributes != 0 || context.Config.GpPassthrough)
                 {
                     DeclareInputAttributes(context, info);
 
                     context.AppendLine();
                 }
 
-                if (info.OAttributes.Count != 0 || context.Config.Stage != ShaderStage.Fragment)
+                if (context.Config.UsedOutputAttributes != 0 || context.Config.Stage != ShaderStage.Fragment)
                 {
                     DeclareOutputAttributes(context, info);
 
@@ -404,24 +402,14 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
 
         private static void DeclareInputAttributes(CodeGenContext context, StructuredProgramInfo info)
         {
-            if (context.Config.GpPassthrough)
+            int usedAttribtes = context.Config.UsedInputAttributes;
+            while (usedAttribtes != 0)
             {
-                for (int attr = 0; attr < MaxAttributes; attr++)
-                {
-                    DeclareInputAttribute(context, info, attr);
-                }
+                int index = BitOperations.TrailingZeroCount(usedAttribtes);
 
-                foreach (int attr in info.IAttributes.OrderBy(x => x).Where(x => x >= MaxAttributes))
-                {
-                    DeclareInputAttribute(context, info, attr);
-                }
-            }
-            else
-            {
-                foreach (int attr in info.IAttributes.OrderBy(x => x))
-                {
-                    DeclareInputAttribute(context, info, attr);
-                }
+                DeclareInputAttribute(context, info, index);
+
+                usedAttribtes &= ~(1 << index);
             }
         }
 
@@ -440,8 +428,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
                 };
             }
 
-            string pass = context.Config.GpPassthrough && !info.OAttributes.Contains(attr) ? "passthrough, " : string.Empty;
-
+            string pass = (context.Config.PassthroughAttributes & (1 << attr)) != 0 ? "passthrough, " : string.Empty;
             string name = $"{DefaultNames.IAttributePrefix}{attr}";
 
             if ((context.Config.Options.Flags & TranslationFlags.Feedback) != 0)
@@ -461,34 +448,14 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
 
         private static void DeclareOutputAttributes(CodeGenContext context, StructuredProgramInfo info)
         {
-            if (context.Config.Stage == ShaderStage.Fragment || context.Config.GpPassthrough)
+            int usedAttribtes = context.Config.UsedOutputAttributes;
+            while (usedAttribtes != 0)
             {
-                DeclareUsedOutputAttributes(context, info);
-            }
-            else
-            {
-                DeclareAllOutputAttributes(context, info);
-            }
-        }
+                int index = BitOperations.TrailingZeroCount(usedAttribtes);
 
-        private static void DeclareUsedOutputAttributes(CodeGenContext context, StructuredProgramInfo info)
-        {
-            foreach (int attr in info.OAttributes.OrderBy(x => x))
-            {
-                DeclareOutputAttribute(context, attr);
-            }
-        }
-
-        private static void DeclareAllOutputAttributes(CodeGenContext context, StructuredProgramInfo info)
-        {
-            for (int attr = 0; attr < MaxAttributes; attr++)
-            {
-                DeclareOutputAttribute(context, attr);
-            }
+                DeclareOutputAttribute(context, index);
 
-            foreach (int attr in info.OAttributes.OrderBy(x => x).Where(x => x >= MaxAttributes))
-            {
-                DeclareOutputAttribute(context, attr);
+                usedAttribtes &= ~(1 << index);
             }
         }
 
diff --git a/Ryujinx.Graphics.Shader/CodeGen/Glsl/GlslGenerator.cs b/Ryujinx.Graphics.Shader/CodeGen/Glsl/GlslGenerator.cs
index e1da1a56..6ea700ac 100644
--- a/Ryujinx.Graphics.Shader/CodeGen/Glsl/GlslGenerator.cs
+++ b/Ryujinx.Graphics.Shader/CodeGen/Glsl/GlslGenerator.cs
@@ -49,46 +49,6 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
 
             Declarations.DeclareLocals(context, function);
 
-            if (funcName == MainFunctionName)
-            {
-                // Some games will leave some elements of gl_Position uninitialized,
-                // in those cases, the elements will contain undefined values according
-                // to the spec, but on NVIDIA they seems to be always initialized to (0, 0, 0, 1),
-                // so we do explicit initialization to avoid UB on non-NVIDIA gpus.
-                if (context.Config.Stage == ShaderStage.Vertex)
-                {
-                    context.AppendLine("gl_Position = vec4(0.0, 0.0, 0.0, 1.0);");
-                }
-
-                // Ensure that unused attributes are set, otherwise the downstream
-                // compiler may eliminate them.
-                // (Not needed for fragment shader as it is the last stage).
-                if (context.Config.Stage != ShaderStage.Compute &&
-                    context.Config.Stage != ShaderStage.Fragment &&
-                    !context.Config.GpPassthrough)
-                {
-                    for (int attr = 0; attr < Declarations.MaxAttributes; attr++)
-                    {
-                        if (info.OAttributes.Contains(attr))
-                        {
-                            continue;
-                        }
-
-                        if ((context.Config.Options.Flags & TranslationFlags.Feedback) != 0)
-                        {
-                            context.AppendLine($"{DefaultNames.OAttributePrefix}{attr}_x = 0.0;");
-                            context.AppendLine($"{DefaultNames.OAttributePrefix}{attr}_y = 0.0;");
-                            context.AppendLine($"{DefaultNames.OAttributePrefix}{attr}_z = 0.0;");
-                            context.AppendLine($"{DefaultNames.OAttributePrefix}{attr}_w = 1.0;");
-                        }
-                        else
-                        {
-                            context.AppendLine($"{DefaultNames.OAttributePrefix}{attr} = vec4(0.0, 0.0, 0.0, 1.0);");
-                        }
-                    }
-                }
-            }
-
             PrintBlock(context, function.MainBlock);
 
             context.LeaveScope();