1692: Properly handle 'mangle' (yaw pitch roll) entity property.

[kduske]

Closes #1692.

[ericwa]

For light entities, positive pitch should be aiming up (+Z axis) e.g. "0 45 0" is aiming at a 45 degree angle upwards. TB is rendering that as pointing 45 degrees down from the horizontal.

reference: https://shoresofnis.wordpress.com/guides/lighting-basics/ , and also I tested it in my light tool.

It seems that info_intermission uses an incompatible mangle, where the first component is pitch (!?!):
https://quakewiki.org/wiki/info_intermission

I'd look in to this more, but I'm going away for the weekend, I can check it out on Monday though.

[kduske]

Interesting. It looks like info_intermission's interpretation of mangle is identical to how TB interprets the angles property: -pitch yaw roll. I'll add special treatment.

[kduske]

Alright, that should fix both the pitch and the info_intermission stuff, at least for Quake. I have a feeling that we will run into problems with this in other games.

[kduske]

@ericwa If you could have quick glance, that would be great. If you want to look into it in more detail, you're of course welcome to, but I'll merge this in the meantime. If you find more problems, just open new issues and we'll fix them.

[kduske]

As a sidenote, we should express these rules using the EL in the game config files, as they might differ from game to game.