[Not a bug] Acos function cause AL error 0xa003 [4.6.0]

[Apeirogon]

Start gzdoom with attached zip file with doom2 wad. Start new game. Hold w for several seconds, or any other button which move doomguy forward. Observe warning in console.
Close gzdoom.
Open zip archive, open zscript.zc, comment line 31 and uncomment line 30.
Start gzdoom again and repeat previous steps. Warning in console will not appear.

An addition notes, player "arrow" on automap would disappear as soon as you hit teleportation line for thee first time, in first case scenario.

acos_bug.zip

[Graf Zahl]

Have a look at the graph and think a bit: https://en.wikipedia.org/wiki/Inverse_t ... _functions
What most likely happens here is that you pass an out of range value as its argument, get a NaN as return which then wreaks havoc everywhere you pass it.

[Apeirogon]

Ahh yes, values for arccos should be inside [-1, 1] range...