Add bxt_emit_sound

[khanghugo]

Edit: S_StartDynamicSound might be not what I want. It doesn't work per channel as I thought it would. The reason why I changed to S_StartDynamicSound is to avoid doing extra precache mechanism so any sounds can be played. I think I might need to revert two recent changes and then figure out how to do precache (or maybe not).

Edit 2: Never mind, it is good. I am just hallucinating.

Edit 3: After some more playing around, I think I have to make it similar to speak where it emits from where the player view is, rather than player origin. Big TODO in there and I thought it wouldn't come back.

Final edit: This should be good. I learn that the issue I've been having is just misusing the attenuation value. So now there are two options to emit sound with two different commands. Though for normal bxt_emit_sound, precaching might be a bit complicated for me for now to figure out how to do it properly. Meanwhile, bxt_emit_sound_dynamic can do that just fine. The difference between the two beside ability to play any sound is probably a jungle of sphagetti behind those twos. bxt_emit_sound will simply just work while bxt_emit_sound_dynamic might weirdly do something to other channels unless we pick correct channel.

[YaLTeR]

What's the usecase for these commands?

[khanghugo]

To playback sound files very fast that it creates pitch. The way it is done now is to spam flashlight, weapon cycle, use button, speak commands. They only occupy 1-2 channels and the sounds come from the player. This PR exposes the functions and allows to play on different channel along with where the sound is emitted from. It is a less than legit way but it is harmless for any run.

[YaLTeR]

Doesn't that make it even less legit than putting your own audio file and playing it with speak?

[khanghugo]

This is purely performative. It can stay vaporware here. I am fine with that.

Edit: r

[YaLTeR]

Nah, it's fine to get it in. Was just wondering.