Fake Gravity Algo


This is the fake Gravity algo. I have copied this from book “Flash MX 2004 Game Design”.

//————– Copy from here ——————-

// Object require on Stage

// ball:MovieClip – Idally with a circle or whatever you want.

var ymov:Number = 0;
var gravity:Number = 2;
ball.onEnterFrame = function() { 
 ymov += gravity;
 ball._y += ymov;
 if (ball._y>(Stage.height – ball._height)) {
  ball._y = Stage.height – ball._height;
  ymov *= -1;

//————– Stop Copying ——————-

Jump Algo in Flash


I could not fullfill promise that I’ll post daily but I am trying…..

This post is for Flash Developers who are doing game programming.

Open new Flash File, Create one MovieClip and Paste this code on MovieClip (Bad Practice, but focus on what it’s doing)

//————– Copy from here ——————-

//This is settign the initial values onLoad
onClipEvent (load) {

//Speed of the Object
//More Speed will make object go higher in sky....
//This can be mass of the object
startspeed = 10;
//Amount of Gravity, 9.8 is standard Gravity
//Use 0 as gravity and your object will be lost in space
//Will never come down...
//Can be used for animated background, with some random wind algo.
gravity = 9.8;
//Current Status
jumping = false;
//Initial position
startpos = 0;

onClipEvent (enterFrame) {

//If user press up key and object is not jumping
//This will make object jump
if ((Key.isDown(87) or Key.isDown(Key.UP)) and jumping == false) {

jumping = true;
starttime = getTimer()/1000;
startpos = this._y;

}else if(Key.isDown(Key.LEFT)){

_x -=5;

}else if(Key.isDown(Key.RIGHT)){

_x +=5;

if (jumping) {

time = getTimer()/1000-starttime;
_y -= (startspeed-gravity*time);
if (_y>startpos) {

_y = startpos;
jumping = false;




//————– Stop Copying ——————-

This code is taken from http://www.video-animation.com/flash_06.shtml