Maes
I like big butts!
Posts: 8662
Registered: 07-06 |
Nope, no vertical speed cap when falling, but there are some other caps in place when floating or moving up steps:
- Moving up steps is instantaneous, so you could consider this as "infinite" acceleration (z pos is simply modified to the destination's height)
- Floating up/down is done at a maximum rate of +/- 4 mu/tic (map units/tic). It's not even a proper acceleration, as floating is done at a constant speed and the z pos of a monster is simply altered directly.
- There is indeed a GRAVITY constant, defined to be 1 mu/tic per tic, or 1 mu/tic^2. Unlike floating, this is actually applied to momz (to the momentum/speed), so it causes a proper acceleration. However, it's kind of anisotropic: if you had zero vertical speed, you get a -2*GRAVITY acceleration, otherwise -GRAVITY.
If you want to translate mu/tics to "real" speeds, it will depend a lot on which interpretation of Doom's map unit values you buy into.
Commonly accepted/debated ones are:
- 10 map units are a foot.
- 16 map units are a foot.
- 8 map units are a foot.
Personally, I consider 16 horizontal map units to be a foot, and 10 vertical map units to be a foot (this is also kind of confirmed in heretic, where there is a FOOTHEIGHT constant defined to be 10 map units). 8 mu/foot IMHO doesn't fall neatly into either: it's a way too large scale for horizontal dimensions, and also for vertical ones. So for height, 10 mu/foot it is.
A tic is 1/35th of a second, so:
GRAVITY = 1 mu/tic^2 = 1225 mu/sec^2 = 122.5 ft/sec^2 = 40.425 m/sec^2 which is about 4 times stronger than normal gravity. For some reason it's hard to realize this in first person view, but it's easy to see how abnormally fast other objects do fall down (gibs, other players, dead monsters etc.)
@Mr. T (speed of light): that's not what happens: it simply gets harder and harder to accelerate towards it, in a way that is not explained by classical mechanics alone, but there are no speed reversals or slowdown effects simply because you're travelling near that particular speed.
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12-22-11 10:14 
