public static SpvInstruction ApplyUnscaling(
CodeGenContext context,
AstTextureOperation texOp,
SpvInstruction size,
bool isBindless,
bool isIndexed)
{
if (context.Config.Stage.SupportsRenderScale() &&
!isBindless &&
!isIndexed)
{
int index = context.Config.FindTextureDescriptorIndex(texOp);
var pointerType = context.TypePointer(StorageClass.Uniform, context.TypeFP32());
var fieldIndex = context.Constant(context.TypeU32(), 4);
var scaleIndex = context.Constant(context.TypeU32(), index);
if (context.Config.Stage == ShaderStage.Vertex)
{
var scaleCountPointerType = context.TypePointer(StorageClass.Uniform, context.TypeS32());
var scaleCountElemPointer = context.AccessChain(scaleCountPointerType, context.SupportBuffer, context.Constant(context.TypeU32(), 3));
var scaleCount = context.Load(context.TypeS32(), scaleCountElemPointer);
scaleIndex = context.IAdd(context.TypeU32(), scaleIndex, scaleCount);
}
scaleIndex = context.IAdd(context.TypeU32(), scaleIndex, context.Constant(context.TypeU32(), 1));
var scaleElemPointer = context.AccessChain(pointerType, context.SupportBuffer, fieldIndex, scaleIndex);
var scale = context.GlslFAbs(context.TypeFP32(), context.Load(context.TypeFP32(), scaleElemPointer));
var passthrough = context.FOrdEqual(context.TypeBool(), scale, context.Constant(context.TypeFP32(), 1f));
var sizeFloat = context.ConvertSToF(context.TypeFP32(), size);
var sizeUnscaled = context.FDiv(context.TypeFP32(), sizeFloat, scale);
var sizeUnscaledInt = context.ConvertFToS(context.TypeS32(), sizeUnscaled);
return(context.Select(context.TypeS32(), passthrough, size, sizeUnscaledInt));
}
return(size);
}
private static void ApplyScalingInterpolated(CodeGenContext context, SpvInstruction output, SpvInstruction vector, SpvInstruction scale)
{
var vector2Type = context.TypeVector(context.TypeFP32(), 2);
var scaleNegated = context.FNegate(context.TypeFP32(), scale);
var scaleVector = context.CompositeConstruct(vector2Type, scaleNegated, scaleNegated);
var vectorFloat = context.ConvertSToF(vector2Type, vector);
var vectorScaled = context.VectorTimesScalar(vector2Type, vectorFloat, scaleNegated);
var fragCoordPointer = context.Inputs[AttributeConsts.PositionX];
var fragCoord = context.Load(context.TypeVector(context.TypeFP32(), 4), fragCoordPointer);
var fragCoordXY = context.VectorShuffle(vector2Type, fragCoord, fragCoord, 0, 1);
var scaleMod = context.FMod(vector2Type, fragCoordXY, scaleVector);
var vectorInterpolated = context.FAdd(vector2Type, vectorScaled, scaleMod);
context.Store(output, context.ConvertFToS(context.TypeVector(context.TypeS32(), 2), vectorInterpolated));
}
private static SpvInstruction ApplyScaling2D(CodeGenContext context, SpvInstruction vector, int index)
{
var pointerType = context.TypePointer(StorageClass.Uniform, context.TypeFP32());
var fieldIndex = context.Constant(context.TypeU32(), 4);
var scaleIndex = context.Constant(context.TypeU32(), index);
if (context.Config.Stage == ShaderStage.Vertex)
{
var scaleCountPointerType = context.TypePointer(StorageClass.Uniform, context.TypeS32());
var scaleCountElemPointer = context.AccessChain(scaleCountPointerType, context.SupportBuffer, context.Constant(context.TypeU32(), 3));
var scaleCount = context.Load(context.TypeS32(), scaleCountElemPointer);
scaleIndex = context.IAdd(context.TypeU32(), scaleIndex, scaleCount);
}
scaleIndex = context.IAdd(context.TypeU32(), scaleIndex, context.Constant(context.TypeU32(), 1));
var scaleElemPointer = context.AccessChain(pointerType, context.SupportBuffer, fieldIndex, scaleIndex);
var scale = context.Load(context.TypeFP32(), scaleElemPointer);
var ivector2Type = context.TypeVector(context.TypeS32(), 2);
var localVector = context.CoordTemp;
var passthrough = context.FOrdEqual(context.TypeBool(), scale, context.Constant(context.TypeFP32(), 1f));
var mergeLabel = context.Label();
if (context.Config.Stage == ShaderStage.Fragment)
{
var scaledInterpolatedLabel = context.Label();
var scaledNoInterpolationLabel = context.Label();
var needsInterpolation = context.FOrdLessThan(context.TypeBool(), scale, context.Constant(context.TypeFP32(), 0f));
context.SelectionMerge(mergeLabel, SelectionControlMask.MaskNone);
context.BranchConditional(needsInterpolation, scaledInterpolatedLabel, scaledNoInterpolationLabel);
// scale < 0.0
context.AddLabel(scaledInterpolatedLabel);
ApplyScalingInterpolated(context, localVector, vector, scale);
context.Branch(mergeLabel);
// scale >= 0.0
context.AddLabel(scaledNoInterpolationLabel);
ApplyScalingNoInterpolation(context, localVector, vector, scale);
context.Branch(mergeLabel);
context.AddLabel(mergeLabel);
var passthroughLabel = context.Label();
var finalMergeLabel = context.Label();
context.SelectionMerge(finalMergeLabel, SelectionControlMask.MaskNone);
context.BranchConditional(passthrough, passthroughLabel, finalMergeLabel);
context.AddLabel(passthroughLabel);
context.Store(localVector, vector);
context.Branch(finalMergeLabel);
context.AddLabel(finalMergeLabel);
return(context.Load(ivector2Type, localVector));
}
else
{
var passthroughLabel = context.Label();
var scaledLabel = context.Label();
context.SelectionMerge(mergeLabel, SelectionControlMask.MaskNone);
context.BranchConditional(passthrough, passthroughLabel, scaledLabel);
// scale == 1.0
context.AddLabel(passthroughLabel);
context.Store(localVector, vector);
context.Branch(mergeLabel);
// scale != 1.0
context.AddLabel(scaledLabel);
ApplyScalingNoInterpolation(context, localVector, vector, scale);
context.Branch(mergeLabel);
context.AddLabel(mergeLabel);
return(context.Load(ivector2Type, localVector));
}
}
