Buoyancy

Alright so I've been working on this for a bit and decided its time to come on here.
Basically I have a cube, and a plane of "water", I want the cube to go underwater a little bit, come up, then go back under, in smaller and smaller amounts, untill finally it stops.
Like a boat in water, Im trying to make it buoyant.
So I got the Cube to bounce up and down, by simply applying, with some gravity.

If CUBEY#<WATERLEVEL
TranslateEntity CUBE,0,-(GRAVITY*DENSITY*CUBEVOLUME),0
endif 

That makes it bounce, but it never Stops.
So how would you go about making an object "Stop" bouncing eventaully?

I'm not an expert on 3d programming, but I'm pretty sure that if you make a variable to keep track of the amount of times the cube bobs up and down, you should be able to stop it from bobbing after a certain amount of time. Like this:

-----------------------------------------------------------------------------
bob=5

if bob>=1 then
[insert bobbing code here]
bob=bob-1
end if

Thanks, thats what I thought too. But I was trying it earlier, no luck, I could get it to stop, but it wouldn't do it gradually and smoothly.

The cube should settle automatically - you just need to make sure that when in water it's upwards acceleration / force ( bouyancy ) is slightly higher than it's downwards acceleraton / force ( gravity ).

const TIMESTEP# = .005
const Gravity# = 9.8
global Bouyancy# = 10.2

[loop]

Acceleration = Acceleration - Gravity
If entityy( CUBE ) < WATERLEVEL
   Acceleration = Acceleration + Bouyancy
endif

translateentity CUBE, 0, Acceleration * TIMESTEP, 0

[loop]

Just vary the bouyancy factor to have objects surface quicker or slower etc..

Having it stop after a set amount of iterations won't look very good imo.

Stevie

You need something to reduce the bob, which is why it goes forever.

I would have done it something like:

'if entity is not in the water set:
     TimeFromfirstHit#=1.0

'else if entity is in the water,  for each loop/timeperiod set:
     TimeFromfirstHit#=TimeFromfirstHit#*0.8 '(the closer to 1.0 the slower to stop bobbing)
     if TimeFromfirstHit#<0.0001 TimeFromfirstHit#=0.0  '<-infinity catcher


TranslateEntity CUBE,0, -(GRAVITY*DENSITY*CUBEVOLUME)*TimeFromfirstHit#,0

Stevies way above looks good too.

I would use sin/cos that is multiplied by a decreasing energy value "e". Additionally the sinus index "a" may increase/loop faster and faster (like in a rubber relaxing effect).

aspeed#=1.0
e#=2.0
while e>0.1
 a#=(a + aspeed) mod 359
 aspeed=aspeed*1.01
 e=e*0.975
 positionentity cube,0,sin(a)*e,0
 renderworld()
 flip
wend