Revert "Simplify shader uniform buffer access codegen"

This reverts commit 2fe9ebaf118d690be8d0cb302529dd359d7c402b.

Ryujinx.Graphics.Shader/CodeGen/Glsl/Declarations.cs

@@ -206,13 +206,13 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
 
                 context.CBufferDescriptors.Add(new BufferDescriptor(ubName, cbufSlot));
 
-                context.AppendLine("uniform " + ubName);
+                context.AppendLine("layout (std140) uniform " + ubName);
 
                 context.EnterScope();
 
-                string ubSize = "[" + NumberFormatter.FormatInt(Constants.ConstantBufferSize / 4) + "]";
+                string ubSize = "[" + NumberFormatter.FormatInt(Constants.ConstantBufferSize / 16) + "]";
 
-                context.AppendLine("precise float " + OperandManager.GetUbName(context.Config.Stage, cbufSlot) + ubSize + ";");
+                context.AppendLine("vec4 " + OperandManager.GetUbName(context.Config.Stage, cbufSlot) + ubSize + ";");
 
                 context.LeaveScope(";");
             }

Ryujinx.Graphics.Shader/CodeGen/Glsl/Instructions/InstGenMemory.cs

@@ -116,12 +116,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl.Instructions
 
             offsetExpr = Enclose(offsetExpr, src2, Instruction.ShiftRightS32, isLhs: true);
 
-            // TODO: For now this is assumed to be constant
-            // (we only use constant slots right now), but we should also
-            // support non-constant values, necessary for full LDC implementation.
-            int slot = ((AstOperand)src1).Value;
-
-            return OperandManager.GetUniformBufferAccessor(slot, offsetExpr, context.Config.Stage);
+            return OperandManager.GetConstantBufferName(src1, offsetExpr, context.Config.Stage);
         }
 
         public static string LoadGlobal(CodeGenContext context, AstOperation operation)
@@ -508,7 +503,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl.Instructions
             // restrictions.
             int ubOffset = GlobalToStorage.GetStorageCbOffset(stage, slot);
 
-            string ubName = OperandManager.GetUniformBufferAccessor(0, ubOffset, stage);
+            string ubName = OperandManager.GetConstantBufferName(0, ubOffset, stage);
 
             offsetExpr = $"{offsetExpr} - int((floatBitsToUint({ubName}) & {mask}) >> 2)";
 

Ryujinx.Graphics.Shader/CodeGen/Glsl/OperandManager.cs

@@ -93,7 +93,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
                     return NumberFormatter.FormatInt(operand.Value);
 
                 case OperandType.ConstantBuffer:
-                    return GetUniformBufferAccessor(operand.CbufSlot, operand.CbufOffset, stage);
+                    return GetConstantBufferName(operand.CbufSlot, operand.CbufOffset, stage);
 
                 case OperandType.LocalVariable:
                     return _locals[operand];
@@ -105,16 +105,28 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Glsl
             throw new ArgumentException($"Invalid operand type \"{operand.Type}\".");
         }
 
-        public static string GetUniformBufferAccessor(int slot, int offset, ShaderStage stage)
+        public static string GetConstantBufferName(int slot, int offset, ShaderStage stage)
         {
-            return GetUniformBufferAccessor(slot, NumberFormatter.FormatInt(offset), stage);
+            string ubName = GetUbName(stage, slot);
+
+            ubName += "[" + (offset >> 2) + "]";
+
+            return ubName + "." + GetSwizzleMask(offset & 3);
         }
 
-        public static string GetUniformBufferAccessor(int slot, string offsetExpr, ShaderStage stage)
+        public static string GetConstantBufferName(IAstNode slot, string offsetExpr, ShaderStage stage)
         {
-            string ubName = GetUbName(stage, slot);
+            // Non-constant slots are not supported.
+            // It is expected that upstream stages are never going to generate non-constant
+            // slot access.
+            AstOperand operand = (AstOperand)slot;
+
+            string ubName = GetUbName(stage, operand.Value);
+
+            string index0 = "[" + offsetExpr + " >> 2]";
+            string index1 = "[" + offsetExpr + " & 3]";
 
-            return $"{ubName}[{offsetExpr}]";
+            return ubName + index0 + index1;
         }
 
         public static string GetOutAttributeName(AstOperand attr, ShaderStage stage)