1 files changed, 18 insertions, 1 deletions
diff --git a/Ryujinx.Graphics.Shader/Instructions/InstEmitAttribute.cs b/Ryujinx.Graphics.Shader/Instructions/InstEmitAttribute.cs
index 7edf5deb..2f75d248 100644
--- a/Ryujinx.Graphics.Shader/Instructions/InstEmitAttribute.cs
+++ b/Ryujinx.Graphics.Shader/Instructions/InstEmitAttribute.cs
@@ -51,7 +51,7 @@ namespace Ryujinx.Graphics.Shader.Instructions
                         offset |= AttributeConsts.LoadOutputMask;
                     }
 
-                    Operand src = op.P ? AttributePerPatch(offset) : Attribute(offset);
+                    Operand src = op.P ? AttributePerPatch(offset) : CreateInputAttribute(context, offset);
 
                     context.Copy(Register(rd), src);
                 }
@@ -312,5 +312,22 @@ namespace Ryujinx.Graphics.Shader.Instructions
 
             return attr;
         }
+
+        private static Operand CreateInputAttribute(EmitterContext context, int attr)
+        {
+            if (context.Config.Options.TargetApi == TargetApi.Vulkan)
+            {
+                if (attr == AttributeConsts.InstanceId)
+                {
+                    return context.ISubtract(Attribute(AttributeConsts.InstanceIndex), Attribute(AttributeConsts.BaseInstance));
+                }
+                else if (attr == AttributeConsts.VertexId)
+                {
+                    return Attribute(AttributeConsts.VertexIndex);
+                }
+            }
+
+            return Attribute(attr);
+        }
     }
 }
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