Ship physics for Pulse - Analysing the past

[kei]

Hi guys,

It is always difficult to analyse these sort of things without having the actual code available to dig through, but concerning the 'drifting' / side-way behavior of the airbrakes in the older Wipeout's I feel confident enough to make a comment. In Pure the air-brakes seem to add onto the normal steering with the D-Pad or A-Stick giving you a higher reach in the speed of which you're steering. The Z and Y ( in a Y=up world ) orientation of your ship is then adjusted from this variable. In the older Wipeout's it works a little different. The normal steering and air brakes are detached from each other, with the steering influencing your ship over it's Z axis solely, and the air brakes linked to the Y rotation of your ship giving that side-way drifting effect. Now this could actually be exclusively a visual difference, though I wouldn't be surprised if the air-brakes have a slightly different influence on the physics as well. In any case, i do prefer the separated rotation of the ship as seen in the classic games too

Also, the difference in floaty-ness / bounciness of the physics between the PAL and NTSC versions of Wip3out is caused by the 10Hz loss which likely equals a identical reduction of physics calculation cycles. Lesser cycles means that you can travel further downwards into the track before you'll be pushed back, and the closer you get to the track the greater this force will be obviously, hence the bouncing. A similar effect can be seen when experiencing frame-rate drops during multiplay in Pure. A solution would be to have the physics calculated with a rate independent of the rendering, but this is definitely more resource intensive then just having one code cycle per frame.

But there might be something else going on as well. This is Pure speculation however I suspect that in Pure the physics behave a little different while you're in the air from when you're 'on' the track. More in a fashion of the physics in F-Zero .. only then with the track having a hoover influence range, while the older games followed one physics rule under all circumstances. That way it is easier to counter drops from high altitude without bouncing of the track multiple times, even though this could be considered 'cheating' ( or helping ) the physics a little. But since I'm by no means sure about this, maybe one of the Liverpool associates could give some insight ?

In any case, interesting discussion, so keep it coming

Later ~
K