vpkpp: PAK support (Half-Life, PS2)

Why?

The PAK format in the normal GoldSrc and its PS2 version is kinda different, so it does not open at the moment.

Resources to work with

All game files, including the PAK0.PAK files in which main content is stored, since it takes a much size and distributing them here openly may not be good - I sent a link to the full game in Discord.

However, all the other PAK files (i.e. except for the PAK0.PAK files) together as an archive take up less than 10MB in total, so I will at least leave them here openly as attachment to the issue: HL1_PS2_NTSC_SLUS_20066_NO_PAK0.zip

If you suddenly need to look at the code of how the game loads the PAK format, then the file in which the engine + client + server compiled code is located is SLUS_200.66: SLUS_20066.zip

You can look at its decompiled code using one of the listed tools:

• Ghidra + ghidra-emotionengine-reloaded plugin
• IDA Pro

Compiled open-source tools that support this:

• ps2-hl-tools: https://github.com/supadupaplex/ps2-hl-tools/tree/master/release

Documentations and source code of tools that support this:

• ps2-hl-tools (C++): https://github.com/supadupaplex/ps2-hl-tools/tree/master/source/paktool
• Documentation from ps2-hl-tools author: https://github.com/supadupaplex/ps2-hl-tools/blob/master/documentation/PAK.pdf