Hi!
After successfully convert the PSX maps to PC, I wondered if I can do that backwards, i.e. converting PC maps from DMA map editor into PSX readable maps. To achieve that goal, I needed to create my own GMP compressor, which was what I did.
Source code: https://github.com/Valps/gta2-map-compressor
Here is an example of a modified PSX map running on PSX emulator:
Note that we already know how to create scripts for the PSX version of GTA2, so combining map and script modding will give us more possibilities for PSX modding.
There are some little issues, such as this compressor doesn't remove hidden surfaces yet, neither clean gradient slope forbidden sides. I always wondered why they are removed during default compression until this happened:
Besides creating a bad rendering, they will create a semi-invisible wall which in some cases (e.g. the second image) is not desired to happen.
However, it is significantly faster compared with the official map editor compression.
The compressor needs Python 3.x to run, but I will create an executable for it in the future. If you want to test it, you just need to download the two files (the python source code and the .bat file) to execute the GMP compressor.