1
0
Fork 0
mirror of https://github.com/Ryujinx/Ryujinx.git synced 2024-11-11 01:16:41 +00:00
Ryujinx/Ryujinx.Graphics.Shader/CodeGen/Glsl/Instructions/InstGenMemory.cs
riperiperi 79adba4402
Add support for render scale to vertex stage. (#2763)
* Add support for render scale to vertex stage.

Occasionally games read off textureSize on the vertex stage to inform the fragment shader what size a texture is without querying in there. Scales were not present in the vertex shader to correct the sizes, so games were providing the raw upscaled texture size to the fragment shader, which was incorrect.

One downside is that the fragment and vertex support buffer description must be identical, so the full size scales array must be defined when used. I don't think this will have an impact though. Another is that the fragment texture count must be updated when vertex shader textures are used. I'd like to correct this so that the update is folded into the update for the scales.

Also cleans up a bunch of things, like it making no sense to call CommitRenderScale for each stage.

Fixes render scale causing a weird offset bloom in Super Mario Party and Clubhouse Games. Clubhouse Games still has a pixelated look in a number of its games due to something else it does in the shader.

* Split out support buffer update, lazy updates.

* Commit support buffer before compute dispatch

* Remove unnecessary qualifier.

* Address Feedback
2022-01-08 14:48:48 -03:00

800 lines
No EOL
29 KiB
C#

using Ryujinx.Graphics.Shader.IntermediateRepresentation;
using Ryujinx.Graphics.Shader.StructuredIr;
using System;
using static Ryujinx.Graphics.Shader.CodeGen.Glsl.Instructions.InstGenHelper;
using static Ryujinx.Graphics.Shader.StructuredIr.InstructionInfo;
namespace Ryujinx.Graphics.Shader.CodeGen.Glsl.Instructions
{
static class InstGenMemory
{
public static string ImageLoadOrStore(CodeGenContext context, AstOperation operation)
{
AstTextureOperation texOp = (AstTextureOperation)operation;
bool isBindless = (texOp.Flags & TextureFlags.Bindless) != 0;
// TODO: Bindless texture support. For now we just return 0/do nothing.
if (isBindless)
{
switch (texOp.Inst)
{
case Instruction.ImageStore:
return "// imageStore(bindless)";
case Instruction.ImageLoad:
NumberFormatter.TryFormat(0, texOp.Format.GetComponentType(), out string imageConst);
return imageConst;
default:
return NumberFormatter.FormatInt(0);
}
}
bool isArray = (texOp.Type & SamplerType.Array) != 0;
bool isIndexed = (texOp.Type & SamplerType.Indexed) != 0;
string texCall;
if (texOp.Inst == Instruction.ImageAtomic)
{
texCall = (texOp.Flags & TextureFlags.AtomicMask) switch {
TextureFlags.Add => "imageAtomicAdd",
TextureFlags.Minimum => "imageAtomicMin",
TextureFlags.Maximum => "imageAtomicMax",
TextureFlags.Increment => "imageAtomicAdd", // TODO: Clamp value.
TextureFlags.Decrement => "imageAtomicAdd", // TODO: Clamp value.
TextureFlags.BitwiseAnd => "imageAtomicAnd",
TextureFlags.BitwiseOr => "imageAtomicOr",
TextureFlags.BitwiseXor => "imageAtomicXor",
TextureFlags.Swap => "imageAtomicExchange",
TextureFlags.CAS => "imageAtomicCompSwap",
_ => "imageAtomicAdd",
};
}
else
{
texCall = texOp.Inst == Instruction.ImageLoad ? "imageLoad" : "imageStore";
}
int srcIndex = isBindless ? 1 : 0;
string Src(VariableType type)
{
return GetSoureExpr(context, texOp.GetSource(srcIndex++), type);
}
string indexExpr = null;
if (isIndexed)
{
indexExpr = Src(VariableType.S32);
}
string imageName = OperandManager.GetImageName(context.Config.Stage, texOp, indexExpr);
texCall += "(" + imageName;
int coordsCount = texOp.Type.GetDimensions();
int pCount = coordsCount + (isArray ? 1 : 0);
void Append(string str)
{
texCall += ", " + str;
}
string ApplyScaling(string vector)
{
if ((context.Config.Stage.SupportsRenderScale()) &&
texOp.Inst == Instruction.ImageLoad &&
!isBindless &&
!isIndexed)
{
// Image scales start after texture ones.
int scaleIndex = context.Config.GetTextureDescriptors().Length + context.FindImageDescriptorIndex(texOp);
if (pCount == 3 && isArray)
{
// The array index is not scaled, just x and y.
vector = "ivec3(Helper_TexelFetchScale((" + vector + ").xy, " + scaleIndex + "), (" + vector + ").z)";
}
else if (pCount == 2 && !isArray)
{
vector = "Helper_TexelFetchScale(" + vector + ", " + scaleIndex + ")";
}
}
return vector;
}
if (pCount > 1)
{
string[] elems = new string[pCount];
for (int index = 0; index < pCount; index++)
{
elems[index] = Src(VariableType.S32);
}
Append(ApplyScaling("ivec" + pCount + "(" + string.Join(", ", elems) + ")"));
}
else
{
Append(Src(VariableType.S32));
}
if (texOp.Inst == Instruction.ImageStore)
{
VariableType type = texOp.Format.GetComponentType();
string[] cElems = new string[4];
for (int index = 0; index < 4; index++)
{
if (srcIndex < texOp.SourcesCount)
{
cElems[index] = Src(type);
}
else
{
cElems[index] = type switch
{
VariableType.S32 => NumberFormatter.FormatInt(0),
VariableType.U32 => NumberFormatter.FormatUint(0),
_ => NumberFormatter.FormatFloat(0)
};
}
}
string prefix = type switch
{
VariableType.S32 => "i",
VariableType.U32 => "u",
_ => string.Empty
};
Append(prefix + "vec4(" + string.Join(", ", cElems) + ")");
}
if (texOp.Inst == Instruction.ImageAtomic)
{
VariableType type = texOp.Format.GetComponentType();
if ((texOp.Flags & TextureFlags.AtomicMask) == TextureFlags.CAS)
{
Append(Src(type)); // Compare value.
}
string value = (texOp.Flags & TextureFlags.AtomicMask) switch
{
TextureFlags.Increment => NumberFormatter.FormatInt(1, type), // TODO: Clamp value
TextureFlags.Decrement => NumberFormatter.FormatInt(-1, type), // TODO: Clamp value
_ => Src(type)
};
Append(value);
texCall += ")";
if (type != VariableType.S32)
{
texCall = "int(" + texCall + ")";
}
}
else
{
texCall += ")" + (texOp.Inst == Instruction.ImageLoad ? GetMask(texOp.Index) : "");
}
return texCall;
}
public static string LoadAttribute(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
IAstNode src3 = operation.GetSource(2);
if (!(src1 is AstOperand baseAttr) || baseAttr.Type != OperandType.Constant)
{
throw new InvalidOperationException($"First input of {nameof(Instruction.LoadAttribute)} must be a constant operand.");
}
string indexExpr = GetSoureExpr(context, src3, GetSrcVarType(operation.Inst, 2));
if (src2 is AstOperand operand && operand.Type == OperandType.Constant)
{
int attrOffset = baseAttr.Value + (operand.Value << 2);
return OperandManager.GetAttributeName(attrOffset, context.Config, perPatch: false, isOutAttr: false, indexExpr);
}
else
{
string attrExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
attrExpr = Enclose(attrExpr, src2, Instruction.ShiftRightS32, isLhs: true);
return OperandManager.GetAttributeName(attrExpr, context.Config, isOutAttr: false, indexExpr);
}
}
public static string LoadConstant(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
string offsetExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
offsetExpr = Enclose(offsetExpr, src2, Instruction.ShiftRightS32, isLhs: true);
var config = context.Config;
bool indexElement = !config.GpuAccessor.QueryHostHasVectorIndexingBug();
if (src1 is AstOperand operand && operand.Type == OperandType.Constant)
{
bool cbIndexable = config.UsedFeatures.HasFlag(Translation.FeatureFlags.CbIndexing);
return OperandManager.GetConstantBufferName(operand.Value, offsetExpr, config.Stage, cbIndexable, indexElement);
}
else
{
string slotExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
return OperandManager.GetConstantBufferName(slotExpr, offsetExpr, config.Stage, indexElement);
}
}
public static string LoadLocal(CodeGenContext context, AstOperation operation)
{
return LoadLocalOrShared(context, operation, DefaultNames.LocalMemoryName);
}
public static string LoadShared(CodeGenContext context, AstOperation operation)
{
return LoadLocalOrShared(context, operation, DefaultNames.SharedMemoryName);
}
private static string LoadLocalOrShared(CodeGenContext context, AstOperation operation, string arrayName)
{
IAstNode src1 = operation.GetSource(0);
string offsetExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
return $"{arrayName}[{offsetExpr}]";
}
public static string LoadStorage(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
string indexExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
string offsetExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
return GetStorageBufferAccessor(indexExpr, offsetExpr, context.Config.Stage);
}
public static string Lod(CodeGenContext context, AstOperation operation)
{
AstTextureOperation texOp = (AstTextureOperation)operation;
int coordsCount = texOp.Type.GetDimensions();
bool isBindless = (texOp.Flags & TextureFlags.Bindless) != 0;
// TODO: Bindless texture support. For now we just return 0.
if (isBindless)
{
return NumberFormatter.FormatFloat(0);
}
bool isIndexed = (texOp.Type & SamplerType.Indexed) != 0;
string indexExpr = null;
if (isIndexed)
{
indexExpr = GetSoureExpr(context, texOp.GetSource(0), VariableType.S32);
}
string samplerName = OperandManager.GetSamplerName(context.Config.Stage, texOp, indexExpr);
int coordsIndex = isBindless || isIndexed ? 1 : 0;
string coordsExpr;
if (coordsCount > 1)
{
string[] elems = new string[coordsCount];
for (int index = 0; index < coordsCount; index++)
{
elems[index] = GetSoureExpr(context, texOp.GetSource(coordsIndex + index), VariableType.F32);
}
coordsExpr = "vec" + coordsCount + "(" + string.Join(", ", elems) + ")";
}
else
{
coordsExpr = GetSoureExpr(context, texOp.GetSource(coordsIndex), VariableType.F32);
}
return $"textureQueryLod({samplerName}, {coordsExpr}){GetMask(texOp.Index)}";
}
public static string StoreAttribute(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
IAstNode src3 = operation.GetSource(2);
if (!(src1 is AstOperand baseAttr) || baseAttr.Type != OperandType.Constant)
{
throw new InvalidOperationException($"First input of {nameof(Instruction.StoreAttribute)} must be a constant operand.");
}
string attrName;
if (src2 is AstOperand operand && operand.Type == OperandType.Constant)
{
int attrOffset = baseAttr.Value + (operand.Value << 2);
attrName = OperandManager.GetAttributeName(attrOffset, context.Config, perPatch: false, isOutAttr: true);
}
else
{
string attrExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
attrExpr = Enclose(attrExpr, src2, Instruction.ShiftRightS32, isLhs: true);
attrName = OperandManager.GetAttributeName(attrExpr, context.Config, isOutAttr: true);
}
string value = GetSoureExpr(context, src3, GetSrcVarType(operation.Inst, 2));
return $"{attrName} = {value}";
}
public static string StoreLocal(CodeGenContext context, AstOperation operation)
{
return StoreLocalOrShared(context, operation, DefaultNames.LocalMemoryName);
}
public static string StoreShared(CodeGenContext context, AstOperation operation)
{
return StoreLocalOrShared(context, operation, DefaultNames.SharedMemoryName);
}
private static string StoreLocalOrShared(CodeGenContext context, AstOperation operation, string arrayName)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
string offsetExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
VariableType srcType = OperandManager.GetNodeDestType(context, src2);
string src = TypeConversion.ReinterpretCast(context, src2, srcType, VariableType.U32);
return $"{arrayName}[{offsetExpr}] = {src}";
}
public static string StoreShared16(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
string offsetExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
VariableType srcType = OperandManager.GetNodeDestType(context, src2);
string src = TypeConversion.ReinterpretCast(context, src2, srcType, VariableType.U32);
return $"{HelperFunctionNames.StoreShared16}({offsetExpr}, {src})";
}
public static string StoreShared8(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
string offsetExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
VariableType srcType = OperandManager.GetNodeDestType(context, src2);
string src = TypeConversion.ReinterpretCast(context, src2, srcType, VariableType.U32);
return $"{HelperFunctionNames.StoreShared8}({offsetExpr}, {src})";
}
public static string StoreStorage(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
IAstNode src3 = operation.GetSource(2);
string indexExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
string offsetExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
VariableType srcType = OperandManager.GetNodeDestType(context, src3);
string src = TypeConversion.ReinterpretCast(context, src3, srcType, VariableType.U32);
string sb = GetStorageBufferAccessor(indexExpr, offsetExpr, context.Config.Stage);
return $"{sb} = {src}";
}
public static string StoreStorage16(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
IAstNode src3 = operation.GetSource(2);
string indexExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
string offsetExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
VariableType srcType = OperandManager.GetNodeDestType(context, src3);
string src = TypeConversion.ReinterpretCast(context, src3, srcType, VariableType.U32);
string sb = GetStorageBufferAccessor(indexExpr, offsetExpr, context.Config.Stage);
return $"{HelperFunctionNames.StoreStorage16}({indexExpr}, {offsetExpr}, {src})";
}
public static string StoreStorage8(CodeGenContext context, AstOperation operation)
{
IAstNode src1 = operation.GetSource(0);
IAstNode src2 = operation.GetSource(1);
IAstNode src3 = operation.GetSource(2);
string indexExpr = GetSoureExpr(context, src1, GetSrcVarType(operation.Inst, 0));
string offsetExpr = GetSoureExpr(context, src2, GetSrcVarType(operation.Inst, 1));
VariableType srcType = OperandManager.GetNodeDestType(context, src3);
string src = TypeConversion.ReinterpretCast(context, src3, srcType, VariableType.U32);
string sb = GetStorageBufferAccessor(indexExpr, offsetExpr, context.Config.Stage);
return $"{HelperFunctionNames.StoreStorage8}({indexExpr}, {offsetExpr}, {src})";
}
public static string TextureSample(CodeGenContext context, AstOperation operation)
{
AstTextureOperation texOp = (AstTextureOperation)operation;
bool isBindless = (texOp.Flags & TextureFlags.Bindless) != 0;
bool isGather = (texOp.Flags & TextureFlags.Gather) != 0;
bool hasDerivatives = (texOp.Flags & TextureFlags.Derivatives) != 0;
bool intCoords = (texOp.Flags & TextureFlags.IntCoords) != 0;
bool hasLodBias = (texOp.Flags & TextureFlags.LodBias) != 0;
bool hasLodLevel = (texOp.Flags & TextureFlags.LodLevel) != 0;
bool hasOffset = (texOp.Flags & TextureFlags.Offset) != 0;
bool hasOffsets = (texOp.Flags & TextureFlags.Offsets) != 0;
bool isArray = (texOp.Type & SamplerType.Array) != 0;
bool isIndexed = (texOp.Type & SamplerType.Indexed) != 0;
bool isMultisample = (texOp.Type & SamplerType.Multisample) != 0;
bool isShadow = (texOp.Type & SamplerType.Shadow) != 0;
SamplerType type = texOp.Type & SamplerType.Mask;
bool is2D = type == SamplerType.Texture2D;
bool isCube = type == SamplerType.TextureCube;
// 2D Array and Cube shadow samplers with LOD level or bias requires an extension.
// If the extension is not supported, just remove the LOD parameter.
if (isArray && isShadow && (is2D || isCube) && !context.Config.GpuAccessor.QueryHostSupportsTextureShadowLod())
{
hasLodBias = false;
hasLodLevel = false;
}
// Cube shadow samplers with LOD level requires an extension.
// If the extension is not supported, just remove the LOD level parameter.
if (isShadow && isCube && !context.Config.GpuAccessor.QueryHostSupportsTextureShadowLod())
{
hasLodLevel = false;
}
// TODO: Bindless texture support. For now we just return 0.
if (isBindless)
{
return NumberFormatter.FormatFloat(0);
}
string texCall = intCoords ? "texelFetch" : "texture";
if (isGather)
{
texCall += "Gather";
}
else if (hasDerivatives)
{
texCall += "Grad";
}
else if (hasLodLevel && !intCoords)
{
texCall += "Lod";
}
if (hasOffset)
{
texCall += "Offset";
}
else if (hasOffsets)
{
texCall += "Offsets";
}
int srcIndex = isBindless ? 1 : 0;
string Src(VariableType type)
{
return GetSoureExpr(context, texOp.GetSource(srcIndex++), type);
}
string indexExpr = null;
if (isIndexed)
{
indexExpr = Src(VariableType.S32);
}
string samplerName = OperandManager.GetSamplerName(context.Config.Stage, texOp, indexExpr);
texCall += "(" + samplerName;
int coordsCount = texOp.Type.GetDimensions();
int pCount = coordsCount;
int arrayIndexElem = -1;
if (isArray)
{
arrayIndexElem = pCount++;
}
// The sampler 1D shadow overload expects a
// dummy value on the middle of the vector, who knows why...
bool hasDummy1DShadowElem = texOp.Type == (SamplerType.Texture1D | SamplerType.Shadow);
if (hasDummy1DShadowElem)
{
pCount++;
}
if (isShadow && !isGather)
{
pCount++;
}
// On textureGather*, the comparison value is
// always specified as an extra argument.
bool hasExtraCompareArg = isShadow && isGather;
if (pCount == 5)
{
pCount = 4;
hasExtraCompareArg = true;
}
void Append(string str)
{
texCall += ", " + str;
}
VariableType coordType = intCoords ? VariableType.S32 : VariableType.F32;
string AssemblePVector(int count)
{
if (count > 1)
{
string[] elems = new string[count];
for (int index = 0; index < count; index++)
{
if (arrayIndexElem == index)
{
elems[index] = Src(VariableType.S32);
if (!intCoords)
{
elems[index] = "float(" + elems[index] + ")";
}
}
else if (index == 1 && hasDummy1DShadowElem)
{
elems[index] = NumberFormatter.FormatFloat(0);
}
else
{
elems[index] = Src(coordType);
}
}
string prefix = intCoords ? "i" : string.Empty;
return prefix + "vec" + count + "(" + string.Join(", ", elems) + ")";
}
else
{
return Src(coordType);
}
}
string ApplyScaling(string vector)
{
if (intCoords)
{
if ((context.Config.Stage.SupportsRenderScale()) &&
!isBindless &&
!isIndexed)
{
int index = context.FindTextureDescriptorIndex(texOp);
if (pCount == 3 && isArray)
{
// The array index is not scaled, just x and y.
vector = "ivec3(Helper_TexelFetchScale((" + vector + ").xy, " + index + "), (" + vector + ").z)";
}
else if (pCount == 2 && !isArray)
{
vector = "Helper_TexelFetchScale(" + vector + ", " + index + ")";
}
}
}
return vector;
}
Append(ApplyScaling(AssemblePVector(pCount)));
string AssembleDerivativesVector(int count)
{
if (count > 1)
{
string[] elems = new string[count];
for (int index = 0; index < count; index++)
{
elems[index] = Src(VariableType.F32);
}
return "vec" + count + "(" + string.Join(", ", elems) + ")";
}
else
{
return Src(VariableType.F32);
}
}
if (hasExtraCompareArg)
{
Append(Src(VariableType.F32));
}
if (hasDerivatives)
{
Append(AssembleDerivativesVector(coordsCount)); // dPdx
Append(AssembleDerivativesVector(coordsCount)); // dPdy
}
if (isMultisample)
{
Append(Src(VariableType.S32));
}
else if (hasLodLevel)
{
Append(Src(coordType));
}
string AssembleOffsetVector(int count)
{
if (count > 1)
{
string[] elems = new string[count];
for (int index = 0; index < count; index++)
{
elems[index] = Src(VariableType.S32);
}
return "ivec" + count + "(" + string.Join(", ", elems) + ")";
}
else
{
return Src(VariableType.S32);
}
}
if (hasOffset)
{
Append(AssembleOffsetVector(coordsCount));
}
else if (hasOffsets)
{
texCall += $", ivec{coordsCount}[4](";
texCall += AssembleOffsetVector(coordsCount) + ", ";
texCall += AssembleOffsetVector(coordsCount) + ", ";
texCall += AssembleOffsetVector(coordsCount) + ", ";
texCall += AssembleOffsetVector(coordsCount) + ")";
}
if (hasLodBias)
{
Append(Src(VariableType.F32));
}
// textureGather* optional extra component index,
// not needed for shadow samplers.
if (isGather && !isShadow)
{
Append(Src(VariableType.S32));
}
texCall += ")" + (isGather || !isShadow ? GetMask(texOp.Index) : "");
return texCall;
}
public static string TextureSize(CodeGenContext context, AstOperation operation)
{
AstTextureOperation texOp = (AstTextureOperation)operation;
bool isBindless = (texOp.Flags & TextureFlags.Bindless) != 0;
// TODO: Bindless texture support. For now we just return 0.
if (isBindless)
{
return NumberFormatter.FormatInt(0);
}
bool isIndexed = (texOp.Type & SamplerType.Indexed) != 0;
string indexExpr = null;
if (isIndexed)
{
indexExpr = GetSoureExpr(context, texOp.GetSource(0), VariableType.S32);
}
string samplerName = OperandManager.GetSamplerName(context.Config.Stage, texOp, indexExpr);
int lodSrcIndex = isBindless || isIndexed ? 1 : 0;
IAstNode lod = operation.GetSource(lodSrcIndex);
string lodExpr = GetSoureExpr(context, lod, GetSrcVarType(operation.Inst, lodSrcIndex));
if (texOp.Index == 3)
{
return $"textureQueryLevels({samplerName})";
}
else
{
string texCall = $"textureSize({samplerName}, {lodExpr}){GetMask(texOp.Index)}";
if (context.Config.Stage.SupportsRenderScale() &&
!isBindless &&
!isIndexed)
{
int index = context.FindTextureDescriptorIndex(texOp);
texCall = "Helper_TextureSizeUnscale(" + texCall + ", " + index + ")";
}
return texCall;
}
}
private static string GetStorageBufferAccessor(string slotExpr, string offsetExpr, ShaderStage stage)
{
string sbName = OperandManager.GetShaderStagePrefix(stage);
sbName += "_" + DefaultNames.StorageNamePrefix;
return $"{sbName}[{slotExpr}].{DefaultNames.DataName}[{offsetExpr}]";
}
private static string GetMask(int index)
{
return '.' + "rgba".Substring(index, 1);
}
}
}