1 files changed, 134 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs b/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs
new file mode 100644
index 00000000..206facd4
--- /dev/null
+++ b/src/Ryujinx.Graphics.Shader/Translation/HelperFunctionManager.cs
@@ -0,0 +1,134 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System;
+using System.Collections.Generic;
+
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
+
+namespace Ryujinx.Graphics.Shader.Translation
+{
+    class HelperFunctionManager
+    {
+        private readonly List<Function> _functionList;
+        private readonly Dictionary<HelperFunctionName, int> _functionIds;
+        private readonly ShaderStage _stage;
+
+        public HelperFunctionManager(List<Function> functionList, ShaderStage stage)
+        {
+            _functionList = functionList;
+            _functionIds = new Dictionary<HelperFunctionName, int>();
+            _stage = stage;
+        }
+
+        public int GetOrCreateFunctionId(HelperFunctionName functionName)
+        {
+            if (_functionIds.TryGetValue(functionName, out int functionId))
+            {
+                return functionId;
+            }
+
+            Function function = GenerateFunction(functionName);
+            functionId = _functionList.Count;
+            _functionList.Add(function);
+            _functionIds.Add(functionName, functionId);
+
+            return functionId;
+        }
+
+        private Function GenerateFunction(HelperFunctionName functionName)
+        {
+            return functionName switch
+            {
+                HelperFunctionName.TexelFetchScale => GenerateTexelFetchScaleFunction(),
+                HelperFunctionName.TextureSizeUnscale => GenerateTextureSizeUnscaleFunction(),
+                _ => throw new ArgumentException($"Invalid function name {functionName}")
+            };
+        }
+
+        private Function GenerateTexelFetchScaleFunction()
+        {
+            EmitterContext context = new EmitterContext();
+
+            Operand input = Argument(0);
+            Operand samplerIndex = Argument(1);
+            Operand index = GetScaleIndex(context, samplerIndex);
+
+            Operand scale = context.Load(StorageKind.ConstantBuffer, 0, Const((int)SupportBufferField.RenderScale), index);
+
+            Operand scaleIsOne = context.FPCompareEqual(scale, ConstF(1f));
+            Operand lblScaleNotOne = Label();
+
+            context.BranchIfFalse(lblScaleNotOne, scaleIsOne);
+            context.Return(input);
+            context.MarkLabel(lblScaleNotOne);
+
+            int inArgumentsCount;
+
+            if (_stage == ShaderStage.Fragment)
+            {
+                Operand scaleIsLessThanZero = context.FPCompareLess(scale, ConstF(0f));
+                Operand lblScaleGreaterOrEqualZero = Label();
+
+                context.BranchIfFalse(lblScaleGreaterOrEqualZero, scaleIsLessThanZero);
+
+                Operand negScale = context.FPNegate(scale);
+                Operand inputScaled = context.FPMultiply(context.IConvertS32ToFP32(input), negScale);
+                Operand fragCoordX = context.Load(StorageKind.Input, IoVariable.FragmentCoord, null, Const(0));
+                Operand fragCoordY = context.Load(StorageKind.Input, IoVariable.FragmentCoord, null, Const(1));
+                Operand fragCoord = context.ConditionalSelect(Argument(2), fragCoordY, fragCoordX);
+                Operand inputBias = context.FPModulo(fragCoord, negScale);
+                Operand inputWithBias = context.FPAdd(inputScaled, inputBias);
+
+                context.Return(context.FP32ConvertToS32(inputWithBias));
+                context.MarkLabel(lblScaleGreaterOrEqualZero);
+
+                inArgumentsCount = 3;
+            }
+            else
+            {
+                inArgumentsCount = 2;
+            }
+
+            Operand inputScaled2 = context.FPMultiply(context.IConvertS32ToFP32(input), scale);
+
+            context.Return(context.FP32ConvertToS32(inputScaled2));
+
+            return new Function(ControlFlowGraph.Create(context.GetOperations()).Blocks, "TexelFetchScale", true, inArgumentsCount, 0);
+        }
+
+        private Function GenerateTextureSizeUnscaleFunction()
+        {
+            EmitterContext context = new EmitterContext();
+
+            Operand input = Argument(0);
+            Operand samplerIndex = Argument(1);
+            Operand index = GetScaleIndex(context, samplerIndex);
+
+            Operand scale = context.FPAbsolute(context.Load(StorageKind.ConstantBuffer, 0, Const((int)SupportBufferField.RenderScale), index));
+
+            Operand scaleIsOne = context.FPCompareEqual(scale, ConstF(1f));
+            Operand lblScaleNotOne = Label();
+
+            context.BranchIfFalse(lblScaleNotOne, scaleIsOne);
+            context.Return(input);
+            context.MarkLabel(lblScaleNotOne);
+
+            Operand inputUnscaled = context.FPDivide(context.IConvertS32ToFP32(input), scale);
+
+            context.Return(context.FP32ConvertToS32(inputUnscaled));
+
+            return new Function(ControlFlowGraph.Create(context.GetOperations()).Blocks, "TextureSizeUnscale", true, 2, 0);
+        }
+
+        private Operand GetScaleIndex(EmitterContext context, Operand index)
+        {
+            switch (_stage)
+            {
+                case ShaderStage.Vertex:
+                    Operand fragScaleCount = context.Load(StorageKind.ConstantBuffer, 0, Const((int)SupportBufferField.FragmentRenderScaleCount));
+                    return context.IAdd(Const(1), context.IAdd(index, fragScaleCount));
+                default:
+                    return context.IAdd(Const(1), index);
+            }
+        }
+    }
+}
+\ No newline at end of file