Hi Lace, yes, I know about that! I've been there too. FYI, the meanings of the variables in that section are as follows (this is for "normal" physics).
p.walkspeed = 0x032c;
p.fallspeed = 0x5ff;
p.fallaccel = 0x50;
p.jumpfallaccel = 0x20;
p.walkaccel = 0x55;
p.jumpwalkaccel = 0x20;
p.decelspeed = 0x33;
p.jumpvelocity = 0x500;
The "walkspeeds" and "fallspeeds" are the maximum velocity you can have. The "accel" speeds are how quickly you will reach that velocity (are added to your current speed every frame up until you get to maxspeed). decelspeed is your friction constant when you are on the ground. jumpvelocity is subtracted from your Y inertia when you first push jump.
I also have written here that the "effective" walk speed is actually only 0x30e, I didn't figure out exactly why but it may have to do with the order of application of the constants or something.
The deceleration constant
p.decelspeed is applied at all times when you are touching the ground, so if you are walking this is in addition to the walk accel. Thus effectively your walkaccel is only 0x22 (It does +0x55, then -0x33).
*1
Jump gravity
p.jumpfallspeed is applied instead of
fallspeed anytime the Jump key is down and you are moving upwards (it does not check whether you are actually jumping).
*2
These constants of course are all bit-shifted by the coordinate scale factor of 9, and applied once per tick at 50fps. Thus a value of 512 means you will move 50 pixels per second.
*1 This is a good thing to know during the first Core battle in Almond. When he tries to blow you against the wall, he pushes against your X inertia with a accelerative force of 0x20. This is less than the p.decelspeed of 0x33, and exactly equal to the p.jumpwalkaccel of 0x20. Therefore, if you stay on the ground, he cannot push you at all because because you have friction against the ground of 0x33. But if you jump eg to avoid one of the shots, you will lose the 0x33 deceleration, and be pushed with 0x20. If you push full against the current, you can cancel it out from pushing you faster, but you will not gain any ground against whatever speed it's already got on you.
*2 This is how the fans work in e.g. Grasstown. You can ride them higher by pushing Jump because when you push the jump key it activates jump gravity, and then you are only falling into them with 0x20 instead of 0x55. You can also see an odd effect here if you find some other way to be moving upwards without jumping. For example, the "hurt hop" when you get hit by an enemy. If you press JUMP right after getting hit, you will fly a lot higher than you're supposed to.
I have a spare one I might, might, be able to send you...
