Shader Printf in HLSL and DX12

[utterances-bot]

Shader Printf in HLSL and DX12

https://therealmjp.github.io/posts/hlsl-printf/

[XanderBert]

Awesome write up!
Definitely going to take a closer look into this!

[mateeeeeee]

Thanks for the article! I am trying to implement this in my engine, however I get compiler errors when trying to use indexing to string literal:
bool b = ("Hello"[2] == 'l'); //error: type mismatch
I was wondering what dxc version you are using because I tried with both latest official release (v1.7.2308) and with the latest successful build's artifacts from Github but it didnt work.

[gevahn]

Slightly less cursed(?) way to get the char code

template<typename T> int CharToUint(in T c) {
	int charCode = -1;
	uint charMapLen = StrLen("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
	for (int i = 0; i < charMapLen; i++) {
		if (c == "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[i]) {
			charCode = LettersStart + i;
			return charCode;
		}
	}
}

[TheRealMJP]

Hey @mateeeeeee, yeah it looks like you need to pass the character to a templated function first for the comparison to work. I imagine that's a side effect of how char and other 8-bit types were disabled in clang/LLVM.

https://godbolt.org/z/asdc76coG

[TheRealMJP]

@gevahn ha nice, I didn't think of that! I guess that's at least more compact than what I came up with.

[mateeeeeee]

@TheRealMJP thanks for the answer. It seems my issue was using DXC_ARG_SKIP_OPTIMIZATIONS (-Od). MRE that shows the issue here
Removing -Od will make it work. I've reported the issue to DXC.