private static void Generate(CodeGenContext context, AstBlock block)
{
AstBlockVisitor visitor = new AstBlockVisitor(block);
var loopTargets = new Dictionary <AstBlock, (SpvInstruction, SpvInstruction)>();
visitor.BlockEntered += (sender, e) =>
{
AstBlock mergeBlock = e.Block.Parent;
if (e.Block.Type == AstBlockType.If)
{
AstBlock ifTrueBlock = e.Block;
AstBlock ifFalseBlock;
if (AstHelper.Next(e.Block) is AstBlock nextBlock && nextBlock.Type == AstBlockType.Else)
{
ifFalseBlock = nextBlock;
}
else
{
ifFalseBlock = mergeBlock;
}
var condition = context.Get(AggregateType.Bool, e.Block.Condition);
context.SelectionMerge(context.GetNextLabel(mergeBlock), SelectionControlMask.MaskNone);
context.BranchConditional(condition, context.GetNextLabel(ifTrueBlock), context.GetNextLabel(ifFalseBlock));
}
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));
}
}