Tag Archives: flash

Function Chaining & Classes

By Zevan | April 2, 2009
CLICK HERE TO COPY
Actionscript:
  1. package {
  2.     import flash.display.Sprite;
  3.     public class Chaining extends Sprite{
  4.         public function Chaining(){
  5.               print(n(100).divide(2).plus(2));
  6.               // outputs 52              
  7.               print(n(100).plus(n(10).multiply(2)));
  8.               // outputs 120
  9.         }
  10.     }
  11. }
  12.  
  13. function print(n:Num):void{
  14.    trace(n.getValue());
  15. }
  16. function n(n:Number):Num{
  17.    return new Num(n);
  18. }
  19.  
  20. class Num{
  21.     private var value:Number;
  22.    
  23.     public function Num(n:Number):void{
  24.        value = n;
  25.     }
  26.     private function convert(n:*):Number{
  27.         if (n is Num) n = n.getValue();
  28.         return n;
  29.     }
  30.     public function getValue():Number{
  31.         return value;
  32.     }
  33.     public function plus(n:*):Num{
  34.         n = convert(n);
  35.         value += n;
  36.         return this;
  37.     }
  38.     public function minus(n:*):Num{
  39.         n = convert(n);
  40.         value -= n;
  41.         return this;
  42.     }
  43.     public function multiply(n:*):Num{
  44.         n = convert(n);
  45.         value *= n;
  46.         return this;
  47.     }
  48.     public function divide(n:*):Num{
  49.         n = convert(n);
  50.         value /= n;
  51.         return this;
  52.     }
  53. }

This snippet is meant to be run as a document class. It shows how one might go about designing a class to make extensive use of function chaining.

Posted in OOP, functions | Also tagged | 2 Comments

Save BitmapData to your HD

By Zevan | April 1, 2009
CLICK HERE TO COPY
Actionscript:
  1. import com.adobe.images.JPGEncoder;
  2.  
  3. var jpgEncoder:JPGEncoder = new JPGEncoder(80);
  4. var file:FileReference = new FileReference();
  5. var id:int = 0;
  6.  
  7. var bit:BitmapData = new BitmapData(400, 400, false, 0x000000);
  8. addChild(new Bitmap(bit));
  9.  
  10. stage.addEventListener(MouseEvent.CLICK, onClick);
  11. function onClick(evt:MouseEvent):void{
  12.     // draw some perlin noise
  13.     bit.perlinNoise(200,200, 2, Math.random()*100, true, false,0, true);
  14.     //bit.draw(someClip);
  15.     //bit.draw(someVideo);
  16.     id++;
  17.     file.save(jpgEncoder.encode(bit), "image_" +id+".jpg");
  18. }

This snippet uses the as3corelib which you can download on this page. It uses the JPGEncoder class to save a jpeg image to a users HD. It also makes use of the flash player 10 FileReference.save() method.

I used BitmapData.perlinNoise() to quickly create an arbitrary image.... as the code comments suggest you could easily snapshot a video or other DisplayObject.

Posted in BitmapData, misc | Also tagged | 3 Comments

Closed Catmull-Rom

By Zevan | March 31, 2009
CLICK HERE TO COPY
Actionscript:
  1. var canvas:BitmapData = new BitmapData(400,400,false, 0x000000);
  2. addChild(new Bitmap(canvas));
  3.  
  4. var pnts:Array = new Array();
  5. // make control points
  6. for (var i:int = 0; i<5; i++){
  7.     var t:Number = i * 72 * Math.PI /180;
  8.     pnts.push(dot(200 + 100 * Math.cos(t),200 +100 * Math.sin(t)));  
  9. }
  10.  
  11. addEventListener(Event.ENTER_FRAME, onLoop);
  12. function onLoop(evt:Event):void {
  13.     canvas.lock();
  14.     canvas.fillRect(canvas.rect, 0x000000);
  15.     curve(pnts);
  16.     canvas.unlock();
  17. }
  18.  
  19. function tangent(pk1:Sprite, pk_1:Sprite){
  20.     return new Point((pk1.x - pk_1.x) / 2, (pk1.y - pk_1.y) / 2);
  21. }
  22.  
  23. // all math from http://en.wikipedia.org/wiki/Cubic_Hermite_spline
  24. function curve(p:Array, res:Number=.03):void{
  25.     var px:Number = 0;
  26.     var py:Number = 0;
  27.     var pIter:int = p.length - 1;
  28.     var m:Array = [];
  29.    
  30.     m[0] = tangent(p[1] ,  p[pIter]);
  31.     for (var i:int = 1; i<pIter; i++){
  32.         m[i] = tangent(p[i + 1], p[i - 1]);
  33.     }
  34.     m[pIter] = tangent(p[0],p[pIter-1]);
  35.    
  36.     for (var t:Number = 0; t <1; t+=res){
  37.          var t_2:Number = t * t;
  38.          var _1_t:Number = 1 - t;
  39.          var _2t:Number = 2 * t;
  40.          
  41.          var h00:Number =  (1 + _2t) * (_1_t) * (_1_t);
  42.          var h10:Number =  t  * (_1_t) * (_1_t);
  43.          var h01:Number =  t_2 * (3 - _2t);
  44.          var h11:Number =  t_2 * (t - 1);
  45.          
  46.          for (var k:int = 0; k <pIter; k++){
  47.              var k1:int = k + 1;
  48.              var pk:Sprite = p[k];
  49.              var pk1:Sprite = p[k1];
  50.              var mk:Point = m[k];
  51.              var mk1:Point = m[k1];
  52.              px = h00 * pk.x + h10 * mk.x + h01 * pk1.x + h11 * mk1.x;
  53.              py = h00 * pk.y + h10 * mk.y + h01 * pk1.y + h11 * mk1.y;
  54.              canvas.setPixel(px, py, 0xFFFFFF);
  55.          }
  56.           pk = p[k];
  57.           pk1 = p[0];
  58.           mk = m[k];
  59.           mk1= m[0];
  60.          
  61.           px = h00 * pk.x + h10 * mk.x + h01 * pk1.x + h11 * mk1.x;
  62.           py = h00 * pk.y + h10 * mk.y + h01 * pk1.y + h11 * mk1.y;
  63.           canvas.setPixel(px, py, 0xFFFFFF);
  64.     }
  65. }
  66.  
  67. // draggable dot
  68. function dot(xp:Number, yp:Number, col:uint = 0xFF0000, rad:Number=4):Sprite {
  69.     var s:Sprite = Sprite(addChild(new Sprite));
  70.     s.x = xp;
  71.     s.y = yp;
  72.     with(s.graphics) beginFill(col), drawCircle(0,0,rad);
  73.     s.buttonMode = true;
  74.     s.addEventListener(MouseEvent.MOUSE_DOWN, onDrag);
  75.     return s;
  76. }
  77. function onDrag(evt:MouseEvent):void {
  78.     evt.currentTarget.startDrag()
  79. }
  80. stage.addEventListener(MouseEvent.MOUSE_UP, onUp);
  81. function onUp(evt:MouseEvent):void{
  82.     stopDrag();
  83. }

This a variation on a post from a few days ago. This shows how to create a closed Catmull Rom spline.

See the other Catmull-Rom related Posts

Posted in Math, graphics algorithms, setPixel | Also tagged | 2 Comments

Hippopede

By Zevan | March 30, 2009
CLICK HERE TO COPY
Actionscript:
  1. x=stage.stageWidth/2;
  2. y=stage.stageHeight/2;
  3. var xp:Number = 0, yp:Number = 0;
  4. var r:Number = 0, t:Number = 0;
  5. var speed:Number=.1;
  6.  
  7. var range:Number=.2;
  8. var b:Number = 20;
  9. var a:Number = b * range;
  10. var orbit:Number = 2 * Math.PI + speed;
  11.  
  12. graphics.lineStyle(0,0x000000);
  13.  
  14. addEventListener(Event.ENTER_FRAME, onLoop);
  15. function onLoop(evt:Event):void {
  16.     var sin:Number=Math.sin(t);
  17.     r =  Math.sqrt(4 * b * (a - b * (sin * sin)));
  18.     xp= r * Math.cos(t);
  19.     yp= r * sin;
  20.    
  21.     if (t==0) {
  22.         graphics.moveTo(xp, yp);
  23.     } else {
  24.         graphics.lineTo(xp, yp);
  25.     }
  26.  
  27.     t += speed;
  28.    
  29.     if (t> orbit) {
  30.         range += .5;
  31.         a= b * range;
  32.         t= 0;
  33.     }
  34. }

The above draws a Hippopede

Posted in Graphics, Math, motion | Also tagged | Leave a comment