Zombie Ninjas available for Android
The beta of Zombie Ninjas has finally been published on Android Market!
https://market.android.com/details?id=air.au.com.escapetheory.ZombieNinjasGame
The development cycle from Flash to Android is now complete 
Still to come:
- Sounds
- Music
- Leaderboards
- Sharing on Facebook
I will make another post when the game is complete with music, sound and a working leaderboard!
Flexperiment 1: Physics of a Bouncing, throwable ball.
Here is a simple bit of code that demonstrates simulated physics of a ball being thrown (written with my colleague Anthony http://www.creatistblog.com/):
The keystone of this experiment is the ENTER FRAME event function that tracks the motion of the ball, applying horizontal 'drag' and vertical 'gravity' as well as spelling out the boundaries of the ball's movement area. A simple hack forces the ball to stop in its tracks when it is at a certain speed and distance from the 'ground' or bottom of the screen. Understanding the physics of something like a bouncing ball helps me build on top of it with more features (such as a true collision detection system, or adding wind).
package { import flash.display.Graphics; import flash.display.Sprite; import flash.events.*; [ SWF( frameRate="60", width="420", height="420", backgroundColor="0x000000" ) ] public class BouncingBall extends Sprite { private var maxSpeed:Number = 100; private var radius:Number = 25; private var vx:Number; private var vy:Number; private var ball:Sprite; private var previousMouseX:Number=0; private var previousMouseY:Number=0; private var currentMouseX:Number; private var currentMouseY:Number; private var throwX:Number; private var throwY:Number; public function BouncingBall() { ball = new Sprite(); ball.buttonMode=true; ball.addEventListener(MouseEvent.MOUSE_DOWN, ballDownHandler); ball.addEventListener(MouseEvent.MOUSE_UP, ballUpHandler); addChild( ball ); ball.x = Math.random() * ( stage.stageWidth - radius ); ball.y = Math.random() * ( stage.stageHeight - radius ); vx = Math.random() * maxSpeed + 0.5; vy = Math.random() * maxSpeed + 0.5; var g:Graphics = ball.graphics; g.beginFill( 0xFF0000 ); g.drawCircle( 0, 0, radius ); g.endFill(); addEventListener( Event.ENTER_FRAME, onClipEnterFrame, false, 0, true ); } private function onClipEnterFrame( p_event:Event ):void { currentMouseX = this.mouseX; currentMouseY = this.mouseY; ball.x += vx; ball.y += vy; if ( vy != 0 ) vy += 0.5; if ( vx != 0 ) vx += (0-vx)*0.015; if ( ( ball.x <= radius && vx < 0 ) || ( ball.x >= stage.stageWidth - radius && vx > 0 ) ) { vx = -vx * 0.6; } if ( ( ball.y <= radius && vy < 0 ) || ( ball.y >= stage.stageHeight - radius && vy > 0 ) ) { vy = -vy * 0.6; } if ( Math.abs( vx ) < 0.01 ) vx = 0; if ( Math.abs( vy ) < 0.1 && ball.y>=stage.stageHeight-radius-2){ vy = 0; ball.y=stage.stageHeight-radius; } throwX = currentMouseX - previousMouseX; throwY = currentMouseY - previousMouseY; previousMouseX = currentMouseX; previousMouseY = currentMouseY; } public function ballDownHandler(e:MouseEvent):void{ ball.startDrag(true); vy = vx = 0; } public function ballUpHandler(e:MouseEvent):void{ ball.stopDrag(); vx = throwX; vy = throwY - 0.6; } } }
Tween Class Tweens Freezing Halfway Through Animation
When creating multiple Tween instances using the Flash Tween classes, animations randomly freeze.
Error type: Bug
Error class: -
How to Induce error:
Using the built-in Flash Tween classes, create multiple tweens on one or more objects.
When these tweens are all firing , Flash randomly 'cleans up' the tween instance while it is still animating. In effect, the animation appears to freeze.
Further tween instances can unfreeze the animation, but clearly this is too annoying to ignore!
Solution:
We can store the tween instance in an Array, and clear the instance when the tween is no longer required. This forces the Flash garbage collector to stop destroying your tween instance:
var tweensArray:Array = []; var tween_count:Number = 0; function tweenFunc():void{ tweensArray[tween_count] = new Tween(myObj, "alpha", Strong.easeOut, myObj.alpha, 1, 0.5, true); tween_count++; }
//tween class has FREEZING bug, it removes tweens before they complete when many tweens occur - this is RANDOM.
//in order to stop the removal, we store the tweens in an array, and wipe them out on each changeContent call.
//remove this fix at your own risk!
if(currentContentNumber == showWhichNumber){
tweensArray[tween_count] = new Tween(this['content'+ (showWhichNumber).toString()], "alpha", Strong.easeOut, this['content'+ (showWhichNumber).toString()].alpha, 1, 0.5, true);
tween_count++;
}else{
tweensArray[tween_count] = new Tween(this['content'+ (showWhichNumber).toString()], "alpha", Strong.easeOut, this['content'+ showWhichNumber].alpha, 0, 0.5, true);
tween_count++;
}
}
Finding the base URL of your Flash
One of the most useful 'basic' tools of a Flash developer is to be able to find the URL of your Flash application, and it is very simple:
//in timeline trace(loaderInfo.url); //this returns the path of the Flash application stop();
The reason it is useful is because you can make your application behave differently depending on which environment it is in.
Your application may be expecting a flashvar which is only available if the Flash was embedded in an HTML. In order to test your functionality within the Flash IDE instead of creating two separate projects, you create some logic based on the URL of the movie:
//in timeline import flash.display.LoaderInfo; var myVar:String; <pre>var paramObj:Object;</pre> if(loaderInfo.url.indexOf('file://')==0){ //if the URL begins with 'file://' it means we're working locally //locally, flashvar is not going to be available //we'll give it a default value myVar = 'foo'; }else{ //we assume that not working locally means we're working live //get flashvar from HTML paramObj = LoaderInfo(root.loaderInfo).parameters; //set myVar to equal myLiveVar from the flashvar myVar = paramObj.myLiveVar; } stop();
SWFObject Error passing URI’s and HTML code into flashvars
When passing URL's or HTML code through SWFObject flashvars, some characters cause errors.
Error type: Pitfall
Error class: -
How to Induce error:
Flash file, published as 'example.swf', 550 x 400:
//in timeline import flash.text.TextField; import flash.display.LoaderInfo; //this is for Flashvars var paramObj:Object = LoaderInfo(root.loaderInfo).parameters; var myTextField:TextField = new TextField(); myTextField.width = 400; if(paramObj['testVar']){ trace('found flashvar'); myTextField.text = paramObj['testVar']; }else{ trace('no flashvar found'); myTextField.text = 'no flashvar found'; } addChild(myTextField); stop();
HTML:
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>swfObject demo</title> <script type="text/javascript" src="swfobject.js"></script> </head> <body bgcolor="#ffffff"> <div id="flashcontent"> This text is replaced by the Flash movie. </div> <script type="text/javascript"> var so = new SWFObject("swfObject_flashvar_error.swf", "swfObject_flashvar_error", "550", "400", "8", "#ffffff"); so.addVariable("testVar", "Lots & lots & lots & lots of ampersands"); so.write("flashcontent"); </script> </body> </html>
Ensure that swfObject.js is in the correct location (same folder as the .swf and .html in the above example).
If you are getting the 'no flashvar found' message, make sure you are not accessing the .html through your file system (you will know this if the start of your URL is 'file://' or something similar).
We expect to see the words 'Lots & lots & lots & lots of ampersands.' in the Flash, but if you have the correct file structure on a live environment, you'll find that you can only see the word 'Lots', this is because SWFObject doesn't like the '&' character.
This poses a huge issue with words encoded in different languages, and URL's which typically require several non-standard characters
Solution:
Simply use the encodeURIComponent() function in the HTML on your flashvar values:
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>swfObject demo</title> <script type="text/javascript" src="swfobject.js"></script> </head> <body bgcolor="#ffffff"> <div id="flashcontent"> This text is replaced by the Flash movie. </div> <script type="text/javascript"> var so = new SWFObject("swfObject_flashvar_error.swf", "swfObject_flashvar_error", "550", "400", "8", "#ffffff"); so.addVariable("testVar", encodeURIComponent("Lots & lots & lots & lots of ampersands")); so.write("flashcontent"); </script> </body> </html>
The encodeURIComponent is available for all Mozilla-style browsers, Safari, Opera, Firefox, Chrome and IE versions 5.5 and above. For more information on this workaround, visit the SWFObject FAQ.