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Fps

Kind of class:	class
Inherits from:	CoreObject
Implements:	RunnableInterface
Version:	12/14/06
Author:	Aaron Clinger
Classpath:	org.casaframework.util.Fps
File last modified:	Sunday, 19 August 2007, 13:43:36

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/*
    CASA Framework for ActionScript 2.0
    Copyright (C) 2007  CASA Framework
    http://casaframework.org
    
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    
    This library 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
    Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

import org.casaframework.core.CoreObject;
import org.casaframework.control.RunnableInterface;
import org.casaframework.util.ArrayUtil;
import org.casaframework.time.EnterFrame;
import org.casaframework.time.Stopwatch;

/**
    Calculates the movie's frames per second.
    
    @author Aaron Clinger
    @version 12/14/06
    @since Flash Player 7
    @example
        <code>
            var movieFps:Fps = Fps.getInstance();
            this.movieFps.start();
            
            this.myButton_btn.onRelease = function():Void {
                trace(this._parent.movieFps.getFps());
            }
        </code>
*/

class org.casaframework.util.Fps extends CoreObject implements RunnableInterface {
    private static var $fpsInstance:Fps;
    private var $pulseInstance:EnterFrame;
    private var $frameTimes: /*Number*/ Array;
    private var $stopwatch:Stopwatch;
    private var $frameTotal:Number;
    
    /**
        @return {@link Fps} instance.
    */
    public static function getInstance():Fps {
        if (Fps.$fpsInstance == undefined)
            Fps.$fpsInstance = new Fps();
        
        return Fps.$fpsInstance;
    }
    
    private function Fps() {
        super();
        
        this.$stopwatch     = new Stopwatch();
        this.$frameTimes    = new Array();
        this.$pulseInstance = EnterFrame.getInstance();
        
        this.setFramesToAverage(20);
        
        this.$setClassDescription('org.casaframework.util.Fps');
    }
    
    /**
        Calculates the current frames per second of the movie.
        
        @return The FPS.
    */
    public function getFps():Number {
        return 1000 / ArrayUtil.average(this.$frameTimes);
    }
    
    /**
        Defines the amount of frames the class compares and averages.
        
        @param total: The amount of previous frames to average; defaults to <code>20</code>.
    */
    public function setFramesToAverage(total:Number):Void {
        this.$frameTotal = total;
    }
    
    /**
        Starts observing the FPS and actively records and calulates the FPS.
    */
    public function start():Void {
        this.$stopwatch.start();
        this.$pulseInstance.addEventObserver(this, EnterFrame.EVENT_ENTER_FRAME, '$onEnterFrame');
    }
    
    /**
        Stops observing the FPS.
    */
    public function stop():Void {
        this.$pulseInstance.removeEventObserver(this, EnterFrame.EVENT_ENTER_FRAME, '$onEnterFrame');
    }
    
    private function $onEnterFrame():Void {
        this.$stopwatch.stop();
        this.$frameTimes.push(this.$stopwatch.getTime());
        
        if (this.$frameTimes.length > this.$frameTotal)
            this.$frameTimes.splice(0, 1);
        
        this.$stopwatch.start();
    }
}

Calculates the movie's frames per second.

Since:

Flash Player 7

Example:

var movieFps:Fps = Fps.getInstance();
this.movieFps.start();

this.myButton_btn.onRelease = function():Void {
    trace(this._parent.movieFps.getFps());
}