How to use a stretch modifier to simulate a rubber bouncing ball.

BallBounce.cs

[cc lang=”c#”]using UnityEngine;

[ExecuteInEditMode]
public class BallBounce : MonoBehaviour
{
public float ground = 0.0f; // Ground position
public float radius = 1.0f; // radius of the ball/object
public float vel = 0.0f; // vertical velocity
public float spring = 10.0f; // spring rate of the object
public float py = 1.0f; // vertical position
public float mass = 1.0f; // objects mass
public float timescale = 1.0f; // time multiplier

MegaStretch mod;
MegaModifyObject modobj;

// Simple physics timsetp
void FixedUpdate()
{
float t = Time.fixedDeltaTime * timescale;
float fy = -9.81f * t;

if ( py < ground ) fy += (spring * (ground - py)) / mass; vel += fy * t; py += vel * t; } void Update() { // Find the stretch mod if ( !mod ) { mod = GetComponent();
modobj = GetComponent();
}

if ( mod )
{
Vector3 pos = transform.position;

float amt = py – ground;

if ( amt > 0.0f )
amt = 0.0f;

float y = py;
if ( y < ground ) y = ground; if ( mod.amount == 0.0f && amt == 0.0f ) modobj.enabled = false; else modobj.enabled = true; mod.amount = (amt / radius); pos.y = y; transform.position = pos; } } }[/cc]

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