Kodewerx

I finally got around to fixing that stupid Jesus Mode code. It's been broke since I made it. I only tested the thing in Kokiri forest as young link. Using it anywhere else made Link jump WAY up in the air when he hit the water. Annoying. Today I finally got around to looking at the code again to figure out WTF.

The original code did some fun FPU maths to approximate the correct "ground" coordinate based on the water level. As it turns out, the water level is always the same, no matter where you go: 32.0.

However, the ground level (ground's Y-coordinate) does not match. In Kokiri Forest, the code sets the coordinate to -12.0 which is perfect for walking on water in that area. In the Great Deku Tree, the Y-coordinate must be set to -896.0! Seriously, what the fuck?

After several hours trying to figure this thing out, I eventually came to realize that the water level doesn't change because it's the actual point of reference for the collision detection. Magically, right next to the ground level is the water level offset... I don't know what else to call it, but the closer that offset is to 0, the closer Link is to the water level. Basically what we want is that ... when it hits 0 (or below), we want to bump the ground level up so that the water level offset remains exactly at 0. Since I couldn't find any reliable way to convert the water level point of reference (or offset) to a proper ground coordinate, I decided the next best thing would be just adding the water level offset to the ground level when the water level offset is below 0. (Yeah, I also won't have any idea what the hell any of this means when I come back and reread it later.)

Anyway, that's all the new code does. If I'm lucky, it will also work as adult Link, but I'll never know until someone can test it. But here it is, in all its glory, and 8 lines shorter than the original. Hooray optimization and bug fixes++!

Except, it does have one bug I noticed. Exiting the Great Deku Tree makes Link jump a bit. I think that probably happens because you exit the Great Deku Tree at a position lower than the water level in the area (but this should not matter -- the water is in a totally different part of the map. This game is not like Mario 64, where the water level is the same everywhere in the map. The game engine is more advanced. It's actually the same game engine between the two games, just Zelda's is greatly updated... *sigh*) Maybe that can be fixed somehow, too. But it's going to add a few more lines to the code again, crap.

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Based on how v2.0 works, it may take a few frames for the ground level to rise to the water level. If you jump off a ledge into very deep water, it may even take a few seconds? Can someone test it in Lake Hylia?

For v3.0, I should investigate the possibility of adding the water level offset to Link's Y-coordinate, and using that as the new ground level. If it works, it should be "perfect" with no frame delay, like v2.0 has. Also, I need to fix the bug that causes Link to jump when exiting the Great Deku Tree... ugh.

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I have to return some video tapes.

Feed me a stray cat.

Bad news! When jumping into deep water with v2.0, it can take up to 5 seconds for the ground level to catch up to the water level. So Link will jump in the water and swim for a little bit and then gain Jesus-like powers and begin walking on water.

Good news! I was right! I can use Link's Y-coordinate instead of the current ground level to set the new ground level to the water level. Actually, I had to set it to Y-coordinate + 7.5. Go figure. But now the ground level will be set correctly within 3 frames of touching the water, no matter how deep the water is, and no matter what the real water level is.

While I was at it, I also found a simple solution to the jumping problem when moving between some areas (like exiting the Great Deku Tree, and entering Queen Ghoma's lair). The fix just involves checking the current ground level. If it's 0, ignore it...

And here's v3.0, probably going to be totally final. (Hooray! It's only two lines longer than the original code! And it actually works this time!)

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I have to return some video tapes.

Feed me a stray cat.

Nice

This gives me even more info concerning the coordinate system and its behavior and interaction with other elements. Now, whenever I get around to hacking OoT again, it will be that much easier to toy with swimming everywhere.

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I may be lazy, but I can...zzzZZZzzzZZZzzz...

GameHacking.org

I enjoyed reading your post.

Jesus WIP


Unfortunately, your post wasn't actually much help for Majora's Mask (though I was expecting it would be..).
That screenshot relies on only 2 pokes. Of course, with simplicity like that, there's like 200 side effects and it only works there.
I'll have to work that out. hahah

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Nice...

If you think it will help, I can try to dig up my notes from hacking the code for Ocarina of Time.

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I have to return some video tapes.

Feed me a stray cat.

Much appreciated, but I have it working now.
Though the original route I was taking will lead to swim anywhere and walk under water (with significantly fewer side-effects), it wasn't so great for Mr. Christ. So I found the water offset you spoke of directly next to the ground coord (which I stumbled on when I was screwing with the camera a couple weeks ago) just as you said it would be; The rest was easy.

But, because I'm hacking it emulated via Wii VC, the ASM tends to move wherever it pleases without any sign of a pointer. I wrote an asm routine (previously) to find and dump a pointer to such asm using a simple xor checksum of the target, provided the number of words it includes and a search range. It only updates the pointer when the routine has moved so there's no lag. (it costs ~15 lines but it also makes it region free, so... win?)

I just have to add that 7.5 now and I'll be finished. Because of the (unusually?) large amount of nop instructions in the game, there is exactly enough room to fit the modification into the programing (after sliding a few instructions around to close the gaps).

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Sounds reasonable. You're welcome to port the code to N64, as well. *hint* I probably won't do it.

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I have to return some video tapes.

Feed me a stray cat.

Meh. I don't have a working GS or any emulators so it's very unlikely I'll do it either.

Here's the asm from Majora's Mask as it is on the Wii, if it will make porting it easy for anyone interested.

54A5024E rlwinm r5,r5,0,9,7
90A30A54 stw r5,2644(r3)
7274FF79 andi. r20,r19,65401
80C300DC lwz r6,220(r3)
7CE64214 add r7,r6,r8
80A3015C lwz r5,348(r3)
90A70088 stw r5,136(r7) #writes to the current ground level (only one)
4800000C b 0x80ae4298
60000000 nop
60000000 nop
80E300DC lwz r7,220(r3)
7CE74838 and r7,r7,r9
7CE74214 add r7,r7,r8
B2870090 sth r20,144(r7)
48000008 b 0x80ae42b0
60000000 nop

stw r5,136(r7) is hijacked with the code:

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