Reducing ball speed

[Boz-Lee]

I have a ball which travels at a speed of 20, for example

speed = 20;

I would like it to eventually go to "0".
So as the ball is moving it would slow down from 20,19,18 to 0.
I have used a timer, but couldnt get the results, for example

speed = (getTimer()-1)/1000;

or

t = getTimer()-1)/1000;
_x = speed*t;

Can anyone tell me if I'm on the right track here cos this is doing my head.
I would appreciate any help thankyou...

[T1ger]

on each frame, do this:

code:

---

if (speed>0) {

--speed;

}

---

it will decrease one speed-point per frame.

[crashlanding]

Originally posted by T1ger
on each frame, do this:

code:

---

if (speed>0) {

--speed;

}

---

it will decrease one speed-point per frame.

or you could use setInterval, like this:

code:

---

var interval = setInterval(reduceSpeed, 500);

function reduceSpeed(){

if (speed>0) {

--speed;

}else{

clearInterval(interval);

}



}

---

I think thats all correct. haven't checked and im in a hurry so sorry if its wrong.

[>flashl!ght<]

another way, a little closer to what you were thinking:[

speed*=decay;
_x+=speed;

and you can defined decay onLoad as a number less than 1(and greater than zero).

decay=.85;

NOTE: this method will never actually reach 0, it will only approach infinitly close. so if theres any code which depends on speed==0 then you will need to add something like:

if(Math.round(speed)==0)

so once speed<.5 it gets treated like its zero

[Boz-Lee]

Thanks for the replies and the code looks good but I was hoping to reduce the balls speed by using the timer, that way with what I'm trying to do will give me more flexibility. For example I have a speed set at 20 and it will eventually hit a wall. To bounce off the wall I would have to say "speed = -speed" after collision, but when I do this the speed changes to "-20" and it completely messes up my reducing speed to "0". If I could get the ball bouncing off the wall without it going to "-" then it would make it a whole lot easier from there...

[>flashl!ght<]

if i understand, the code i presented still works under those conditions. it does not reduce speed in a linear fashion like the others. please re-read my post, see if it works. its how i would(and have many times) do it.

[>flashl!ght<]

also, you could have an additional var called "direction" or "dir" which is always 1 or -1, for right and left respectively, then the movement code instead of

_x+=speed;

would be

_x+=(dir*speed);

then on bounce, you simple do

code:

---

if(dir){//this is saying if(dir==1) or if(dir==true) - same thing

	dir=-1;

}else{

	dir=1;

}

---