Grenade Explosion

@author: Dennis Wilson
@see: http://www.abakia.de/

forked:2
favorite:8
lines:138
license : MIT License
modified : 2009-08-14 23:54:58

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package {
        //@author: Dennis Wilson
        //@see: http://www.abakia.de/
        
	import flash.display.*;
	import flash.events.*;
	import flash.filters.*;
	import flash.geom.*;
	import flash.text.TextField;

[SWF(frameRate="75", backgroundColor="#000000")]

public class Explosion extends Sprite {
		public const MAX_W : uint = 500;
		public const MAX_H : uint = 500;
		public const HALF_MAX_W : uint = MAX_W / 2;
		public const HALF_MAX_H : uint = MAX_H / 2;

public const MAX_PARTICLES : uint = 100;
		public const RADIUS : uint = 10;
		public const EXPLODE_SPEED : uint = 5;
		public const PI_DIV_180 : Number = Math.PI / 180;
                public const GRAVITY : Number = 0.5;

public var frame : uint = 0;
                public var particles : Array = [];
        
		public var container : Sprite;
		public var bmpdSmoke : BitmapData;
		public var tf : TextField;
		public var bitmap : Sprite;
		public var bmpdGlow : BitmapData;

public var smokeBlur : BitmapFilter;
		public var fragmentBlur : BitmapFilter;

public var x_shake : Number;
		public var shiver_till: uint = 0;

public function Explosion() {
			stage.scaleMode = StageScaleMode.NO_SCALE;
			stage.align = StageAlign.TOP_LEFT;
			stage.quality = StageQuality.LOW;            
			init();
			addEventListener(Event.ENTER_FRAME, update);
		}

/* Helper */

private function init() : void {
                    smokeBlur = new BlurFilter(2, 10);
                    fragmentBlur = new BlurFilter(15, 10)
                    bmpdSmoke = new BitmapData(MAX_W, MAX_H, true, 0x00ffffff);
                    bmpdGlow = new BitmapData(MAX_W, MAX_H, true, 0x00ffffff);

container = new Sprite();
                    container.x = 0;
                    container.y = 0;
			
		    bitmap = new Sprite();
                    bitmap.addChild(new Bitmap(bmpdSmoke));
                    bitmap.addChild(new Bitmap(bmpdGlow));
		    bitmap.mouseEnabled = true;
		    bitmap.buttonMode = true;
		    bitmap.useHandCursor = true;
                    bitmap.alpha = 1;
                    bitmap.addEventListener(MouseEvent.CLICK, onClick);
                    addChild(bitmap);
            
                    tf = new TextField();
		    tf.text = 'click-click-boom!';
		    tf.x = 10;
		    tf.y = 10;
		    tf.height = 15;
		    tf.blendMode = BlendMode.INVERT;
		    addChild(tf);
		}

private function spawnFragments(x:uint, y:uint) : void {
			var p : Particle;

for(var i : int = 0;i < MAX_PARTICLES; i++) {
			    p = new Particle();
			    p.x = p.x_orig = x;
			    p.y = p.y_orig = y;
                            p.x_to = x + Math.sin((Math.random() * 1) * PI_DIV_180) * (Math.random() * RADIUS);
                            p.y_to = y + Math.cos((Math.random() * 2) * PI_DIV_180) * (Math.random() * RADIUS);

// random power to specified direction.
                            // creepy math. wanna fork? ;-)
                            var a:Number = y - p.y_to; 
                            var c:Number = x - p.x_to;
                            p.x_speed = Math.sin((a/c)) * Math.random()*10;
                            p.y_speed = Math.cos((a/c)) * Math.random()*10;
			    p.perish_at = Math.round(Math.random()*100+20);
			    p.alpha_to = 0.15;
				
			    container.addChild(p); 
			    particles[particles.length] = p;
			}
			shiver_till = frame + 20;
			x_shake = 4;
		}

/* Events */

private function onClick(event : MouseEvent) : void {
			spawnFragments(mouseX, mouseY);
		}

private function update(e : Event = null) : void {
			frame++;
        	
			//move fragments
			var j : Number = 0;
			for each(var p:Particle in particles) {
                            p.x += p.x_speed;
                            p.y += p.y_speed;
			    p.y_speed += GRAVITY;
			    p.alpha = p.alpha + ( p.alpha_to - p.alpha) / 2;

if(p.perish_at < (p.y - p.y_orig)) {
			        p.alpha_to = 0;					
			    }
			    if(p.y > MAX_H) {
		                particles.splice(particles.indexOf(p),1);
                                container.removeChild(p);
                            }
			}
			
                        // shiver
			if(frame <= shiver_till) {
                            bitmap.x = Math.random()*x_shake*Math.sin(frame);
                            bitmap.y = Math.random()*2*Math.sin(frame);
                            x_shake = x_shake + ( 0 - x_shake)/10;
			} else {
                            bitmap.x = 0;
                            bitmap.y = 0;
			}

// draw smoke
                        bmpdSmoke.draw(container, null, null, BlendMode.ADD);
                        bmpdSmoke.draw(container, null, null, BlendMode.ADD);
                        bmpdSmoke.colorTransform(bmpdSmoke.rect, new ColorTransform(1, 1, 1, 1, 0xff, 0xff, 0xff, 0));
                        bmpdSmoke.scroll(0, -2); 
                        bmpdSmoke.applyFilter(bmpdSmoke, bmpdSmoke.rect, new Point(), smokeBlur);

// draw fragments
			bmpdGlow.draw(container, null, null, BlendMode.ADD);
                        bmpdGlow.applyFilter(bmpdGlow, bmpdGlow.rect, new Point(), fragmentBlur);
                        bmpdGlow.draw(container,null,null, BlendMode.ADD);
                        bmpdGlow.draw(container,null,null, BlendMode.ADD);
		}
	}
}

import flash.display.Sprite;

class Particle extends Sprite {
    public var x_to    :Number = 0;
    public var y_to    :Number = 0;
    public var x_orig : Number =0;
    public var y_orig : Number =0;
    public var x_speed : Number = 0;
    public var y_speed : Number = 0;
    public var alpha_to : Number = 1;
    
    public var color : uint = 0;
    public var perish_at:uint=0;
    
    public function Particle() {
        const COLORS:Array = [0xf26700, 0xf29400, 0xff0000];
        color = COLORS[Math.round(Math.random()*(COLORS.length-1))];
		
	graphics.beginFill(color);
	graphics.drawCircle(-2, -2, 2);
	graphics.endFill();
    }
}

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