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Quickreference: flipping DisplayObjects

kajyr — Wed, 19 May 2010 10:00:04 +0000

This one flips DisplayObjects on a vertical or horizontal axe.

public static function flipHorizontal(obj:DisplayObject):void {
var m:Matrix = obj.transform.matrix;
m.transformPoint(new Point(obj.width * .5, obj.height * .5));
m.tx = (m.a > 0)?obj.width + obj.x:obj.x - obj.width;
m.a = -1 * m.a;
obj.transform.matrix = m;
}

public static function flipVertical(obj:DisplayObject):void {
var m:Matrix = obj.transform.matrix;
m.transformPoint(new Point(obj.width * .5, obj.height * .5));
m.ty = (m.d > 0)?obj.y + obj.height:obj.y - obj.height;
m.d = -1 * m.d;
obj.transform.matrix = m;
}

Basic random functions

kajyr — Sat, 28 Nov 2009 13:53:26 +0000

Here are some really basic (but useful) functions that returns random stuff…

The really basic one, is built in the Flash api and it returns a Number between 0 and 1:

var n:Number = Math.random();

A number in a range

Sometime is more useful to have a random number in a different range, let’s say between 15 and 45, instead of 0 and 1.

public static function randNumber(max:Number = 1, min:Number = 0):Number {
return Math.random() * (max - min) + min;
}

Random int

and what if we don’t need decimals? Round’em!

public static function randInt(max:Number = 1, min:Number = 0):int {
return Math.round(Math.random() * (max - min) + min);
}

Random boolean

True or false? Flip a coin.

public static function bool():Boolean {
return (Math.round(Math.random()) == 0);
}

Random sign

-1 or 1; Useful when you have to random select random rotation verse, for example, -1*45 or 1*45, rotates counterclockwise or clockwise.

public static function sign():Number {
return (Math.round(Math.random()) == 0):-1:1;
}

Random color

Really useful when drawing debug shapes on screen..

public static function color():uint {
return Math.random() * 0xFFFFFF;
}

Random point

Inside an area. I like to use the flash.geom.Rectangle struct to describe an area, more than using 4 parameters (Flash api are quite inconsistent about this choice)

public static function point(area:Rectangle):Point {
return new Point(randInt(area.x, area.x + area.width), randInt(area.y, area.y + area.height));
}

Quickreference: display elements in a circle

kajyr — Thu, 30 Jul 2009 13:00:54 +0000

How to display elements in a circle? A small function to do that is:

GeSHi Error: GeSHi could not find the language actionscript3 (using path /nfs/c03/h01/mnt/85630/domains/nightdrops.com/html/wp-content/plugins/snipplr/geshi/geshi/) (code 2)

Parameters are:

items: the items to be displayed a a circle
center: the center of the circle
distance: the distance from the center
initialAngle: the angle of the first item. Zero means that the item wil be aligned orizontally with the center, on his right.

Here’s an example:

Tweening global volume in flash

kajyr — Mon, 08 Jun 2009 14:22:12 +0000

Just a quick reminder on how to shut up the master volume on a flash project. I like a smooth tween to the silence, so I’m using the TweenLite libraries.

GeSHi Error: GeSHi could not find the language actionscript3 (using path /nfs/c03/h01/mnt/85630/domains/nightdrops.com/html/wp-content/plugins/snipplr/geshi/geshi/) (code 2)

The trick here is to tween the volume property of a throw-away SoundTransform object, and on each step of the Tween apply that object as the SoundMixer.soundTransform Object, with an helper function. Note that I’m not going to write the function inside the TweenLite’s partameter list, as it is gross and dirty.

Tweening the volume back to 1 is so easy that I’m not writing it, to not offend anyone.

Quick reference: Drawing a scaled object in Actionscript

kajyr — Mon, 23 Feb 2009 09:43:52 +0000

Just as a quick reference, since I usually forgot each time how to do it.

Assume to have a DisplayObject obj, you want to draw in a Bitmap a scaled snapshot of that object.

Just like when you are drawing thumbs.

GeSHi Error: GeSHi could not find the language actionscript3 (using path /nfs/c03/h01/mnt/85630/domains/nightdrops.com/html/wp-content/plugins/snipplr/geshi/geshi/) (code 2)

Fading out and detaching

kajyr — Thu, 08 Jan 2009 10:27:31 +0000

One class i really do like is TweenLite. I don’t really like the default tweening engine for a couple of reasons, but mainly because i have to save the tween object in a reference in my class, or the garbage collector could eat it (stopping the tweens in a unpredictable status).
TweenLite don’t require this (it exposes static functions, and keep internal references to the tweens) and permits me to specify functions to be called, not only handlers (which i know, may sound a little ActionScript 2.0, but in fact permits to call any funcion, and so avoiding one-line handlers).

One small example, (to be used inside a DisplayObjectContainer) is fading out a child, and detaching after. In one clear line:

GeSHi Error: GeSHi could not find the language actionscript3 (using path /nfs/c03/h01/mnt/85630/domains/nightdrops.com/html/wp-content/plugins/snipplr/geshi/geshi/) (code 2)

Let’s bring this a step further: we can easily apply this technique to all child of a given container:

GeSHi Error: GeSHi could not find the language actionscript3 (using path /nfs/c03/h01/mnt/85630/domains/nightdrops.com/html/wp-content/plugins/snipplr/geshi/geshi/) (code 2)

So now all the time removeChild is called from outside, the child gently fade away, and then quietly removes himself.