bouncing ball without physics/gravity

Questions & Answers
1

Hey, another quick question here from a beginner. II'm playing around with code and right now I'm trying to figure out how to create a bouncing ball without using any physics/force/gravity. I'm basically trying to learn how this kinda coding works so I can apply it to other things that aren't exactly meant to be physics based.. here it is so far(not very far :)):

var YMovement : float = 0;
var damp:float;
var fall:float;
var jump:boolean=false;

function Update ()
{   
    if(jump==false){
    YMovement = Mathf.Lerp(YMovement, -1, Time.deltaTime*damp);
    transform.Translate (0,YMovement * 12 * Time.deltaTime, 0);
    }else if(jump==true){
         transform.position.y+=fall*Time.deltaTime; //???
    }
    }   
function OnTriggerEnter(col:Collider){
    if(col.gameObject.tag=="ground"){
    jump=true;
    }
}

this code is attached to a box that would be bouncing on top of another box tagged as "ground". Right now after the bounce all I have is the ball shooting towards the positive y axis, but the initial fall is the way I want it ..Any pointer on how to do this or if I'm even doing it right would be greatly appreciated.

2

To do it totally programmatically without physics, you can do something like this:

var bounceSpeed = 1.0;
var bounceAmount = 2.0;

function Start () {
    while (true) {
        var t = 0.0;
        while (t < 1.0) {
            t += Time.deltaTime * bounceSpeed;
            transform.position.y = Bounce(t) * bounceAmount;
            yield;
        }
    }
}

function Bounce (t : float) : float {
    return Mathf.Sin(Mathf.Clamp01(t) * Mathf.PI);
}

Edit: actually you can remove the Start function and use this if you wanted the bouncing to continue forever:

function Update () {
    transform.position.y = Bounce((Time.time * bounceSpeed)%1) * bounceAmount;
}

If you wanted to limit the number of bounces, though, then keep the Start function and replace "while (true)" with "for (i = 0; i < 10; i++)" for 10 bounces, etc.

3

This script is simply GREAT!