code4u - DelayedLoop

[leifi]

Hey guys!

Here's an interesting ActionScript 3 class for experienced programmers. It can delay simple 'for loops'. It's very useful for scripts with many loops that take much processing power (e.g. A* search algorithm). Check it out!

You can copy the following script or download the attached sample movie.

Notice that both the code and the sample are released under GNU General Public License.

-------------
DelayedLoop
Version 1.0
-------------

/*
	DelayedLoop
	 Version 1.0
	 code4u projects
	
    Copyright (C) 2009 TreeBytes Interactive

	[NATIVE] + [AS3] only
	

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.




	-HOW IT WORKS-
	
	Just create a new DelayLoop instance.
	
	-----
	
	new DelayedLoop( func:Function ,
					 start:Number,
					 end:Number
					 [,prio:Number] );
	
	func	-	the function that contains the loop script.
	Function	It has to take 1 parameter so that the handler
				can pass the current loop position.
	
	start	-	the start position of the loop.
	Number
	
	end		-	the end position.
	Number
	
	prio	-	(default = 1) the priority of the loop.
	Number		Loops with a higher value will be called
				more often.
				
	+-NOTICE!---------------------------------------+
	| The handler will increase the loop position	|
	| by 1 on every step.							|
	+-----------------------------------------------+
	
	
	-EXAMPLE-
	
	// A simple 'for loop':
	// ------------------
	
	for (var i:uint=0; i < myArray.length; i++)
	{
		myArray[i].foo();
		myArray[i].x += 3;
		root.foo += myArray[i].y;
	}
	


	
	// Now we "delay" this loop:
	// -------------------------
	
	function myloop(i:uint)
	{
		myArray[i].foo();
		myArray[i].x += 3;
		root.foo += myArray[i].y;
	}
	
	var dl = new DelayedLoop(myloop,0,myArray.length);
	
	// That's all!
*/

#if native || as3
class DelayedLoop extends EventDispatcher
{
	static var list:Array = new Array;
	static var setup:Boolean = false;
	static var performanceMaximum:Number;
	static var performanceRaise = 0.25;
	
	var func:Function;
	var end:Number;
	var userPriority:Number;
	var priority:Number;
	var intensity:Number;
	var position:Number;
	
	function DelayedLoop(func:Function,start,end,prio=1)
	{
		this.func = func;
		this.position = Math.abs(start);
		this.end = Math.abs(end);
		this.userPriority = Math.abs(prio);
		this.priority = Math.abs(prio);
		this.intensity = -1;
		
		if (!DelayedLoop.setup)
		{
			root.addEventListener(Event.ENTER_FRAME,DelayedLoop.run);
			DelayedLoop.setup = true;
			DelayedLoop.performanceMaximum = (1000 / (root.stage.frameRate+5))
		}
		
		DelayedLoop.list.push(this);
	}
	
	function call()
	{
		this.func(this.position);
		this.position = this.position+1;
		this.priority = 0;
	}
	
	static function run(e:Event)
	{
		var globtimebef = getTimer();
		var usablePerformance = performanceMaximum;

		list.sortOn("priority",Array.NUMERIC | Array.DESCENDING);
		
		var runs = 0;
		
		while (usablePerformance > 0 && list.length > 0)
		{
			list.sortOn("priority",Array.NUMERIC | Array.DESCENDING);

			var work = DelayedLoop.list[0];
			
			if (work.position < work.end)
			{
				if (work.intensity < usablePerformance)
				{
					var tbef = getTimer();
					work.call();
					var time = getTimer()-tbef;
					work.intensity = time;
					usablePerformance = usablePerformance-time;
					runs++;
				}
			}
			else
			{
				list.removeValue(work);
			}
			usablePerformance--;
			
			for (var a=0; a<list.length; a++)
			{
				list[a].priority = list[a].priority+list[a].userPriority;
			}
		}
		
		if (list.length > 0)
		{
			if (runs == 0)
			{
				work = list[0];
				work.call();
			}
			var globtime = getTimer() - globtimebef;
			
			if(globtime > (1000 / (root.stage.frameRate)))
			{
				performanceMaximum = performanceMaximum-5;
				performanceRaise = performanceRaise / 2;
			}
			else if (performanceMaximum < (1000 / (root.stage.frameRate-5)))
			{
				performanceMaximum = performanceMaximum+performanceRaise;
				performanceRaise = performanceRaise*1.01;
			}
		}
	}
}
#endif

Have fun!