[Technical] [PS2] Gran Turismo 3 PAL .elf modification

Started by forum yoshi, November 05, 2020, 01:30:48 AM

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forum yoshi

Hello.

I've been working on a mod for Gran Turismo 3 PAL (sces_502.94). In the mod, I've modified the car 3D models to use the high-quality menu 3D wheels, which look far better than the almost 2D race wheel models, so it's a significant difference in how the game looks.
I have run into an issue though: The game allocates 688,128 bytes per car model in memory. Some of the modded car models, now bigger in filesize due to high quality wheel models, exceed the limit and start overwriting into other loaded cars, resulting in gfx errors, crashes, and TLB misses. So, the only way to really fix it (I think), as the models cannot be compressed further, is to increase the allocation of memory for the models. But this is very technical, and basically not possible for me to do alone.
It's very annoying that this issue exists, as I've already taken care of all the other issues in the mod, this is the last one!  :D :-\
So, I'm quickly going to list some details that may help anyone with better knowledge in this stuff:
- The length of bytes in memory between each car file header is 688,128 bytes, so I assume the allocated memory size per car is 688,128.
- I once got a TLB miss error, and managed to locate where it came from in the .elf, what the command is, and got it's location in the file in a Hex Editor: 0026BC18, bnezl   v0,pos_0026BC20 (54400001).
- IF it helps at all, I've located where each car model gets loaded in RAM.
If anyone is able to help me fix this, you will be credited in the mod credits as a thank you!
Also, if anyone thinks that they're probably able to help, I can set up a Discord server to ease communication.
Thanks in advance!

forum yoshi

*bump*, still am needing help if anyone can provide any!  :)