PAT file support

[Pinsplash]

Today I stumbled upon something obscure in hl2_pak_dir.vpk. In this VPK's "maps" folder, there are ".pat" files with names matching Half-Life 2 BSPs. These files are plaintext and are capable of adding new entities into maps some time during the game loading it. You can see these entities ingame with commands like ent_text, but since they aren't in the BSP, they aren't there in decompiles. Looking through a single file, it seems like they used this mainly for achievement logic. BSPSource should try to read from a map's associated pat file if possible.

[ata4]

Interesting... so those are like .lmp files but just for entities. Yeah, BSPSource should definitely support those.