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);
}
