Fix DXBC pixel shader debugging with non-zero indexed semantic

[anthark]

Description

While using DirectX 12, DXBC pixel shader debugging doesn't work, when semantic with non-zero index is used between VS and PS stages and is a single semantic with this name. I've added semantic index to generated debug shader input to fix interstage communication between original VS and generated PS, when semantic index is not zero. I kept previous logic as well to not to change behavior when more than one semantics with the same name are used and one of them is not indexed, like COLOR (turns to COLOR0) and COLOR1.

Also very simple application, that reproduces issue is added: it is from official DirectX 12 samples from Microsoft, with COLOR semantic in PS input changed to COLOR1
HelloTriangle.zip

[baldurk]

As a general note, from the CONTRIBUTING documentation please ensure all commits are properly formatted and do not include any formatting-only commits.

[baldurk]

This fix does not seem correct. As in the comments on the field semanticIdxName it already includes the index when necessary as compared to semanticName, so this will duplicate it turning TEXCOORD1 into TEXCOORD11.

Perhaps the logic for that needs to be re-examined? If you're not sure you can open this as a bug report and not a pull request and I can investigate it.

[anthark]

This fix does not seem correct. As in the comments on the field semanticIdxName it already includes the index when necessary as compared to semanticName, so this will duplicate it turning TEXCOORD1 into TEXCOORD11.

Perhaps the logic for that needs to be re-examined? If you're not sure you can open this as a bug report and not a pull request and I can investigate it.

Oh, thanks - I see where I'm wrong =)
I believe root reason for the issue goes from this code:

for(uint32_t i = 0; i < sign->numElems; i++)
{
  SigParameter &a = (*sig)[i];

  for(uint32_t j = 0; j < sign->numElems; j++)
  {
    SigParameter &b = (*sig)[j];
    if(i != j && a.semanticName == b.semanticName)
    {
      a.needSemanticIndex = true;
      break;
    }
  }

  rdcstr semanticIdxName = a.semanticName;
  if(a.needSemanticIndex)
    semanticIdxName += ToStr(a.semanticIndex);

  a.semanticIdxName = semanticIdxName;
  }
}

Which literally means, that we use semantic index as a part of semanticIdxName field only if semantic with given name is used more than once. However if we only use single semantic with given name, but non-zero index, this doesn't work =(

Os, is it OK, if I change it here to add index to the field, when semantic index is not 0?

[baldurk]

That seems to make more sense, it sounds quite unusual to only use a higher numbered semantic but I can see how that would break here.

If you want to update the PR that is fine, please ensure that as noted above you follow the CONTRIBUTING guidelines and remove the old commits and just have a new commit with the correct fix.