Monthly Archives: March 2010

Catmull-Rom Error

By Zevan | March 22, 2010

I was messing with Catumull Rom spline code from awhile back and this this came out:

CLICK HERE TO COPY
Actionscript:
  1. [SWF(width = 500, height= 500)]
  2. var pnts:Array = new Array();
  3. // make 8 control points
  4. for (var i:int = 0; i<8; i++){
  5.     pnts.push(dot(50 + Math.random() * 80 * i, Math.random()*(stage.stageHeight-40)+20));
  6. }
  7. addEventListener(Event.ENTER_FRAME, onLoop);
  8. function onLoop(evt:Event):void {
  9.    
  10.     graphics.clear();
  11.     graphics.lineStyle(0,0);
  12.     curve(pnts);
  13. }
  14. function tangent(pk1:Sprite, pk_1:Sprite){
  15.     return new Point((pk1.x - pk_1.x) / 2, (pk1.y - pk_1.y) / 2);
  16. }
  17. // all math from http://en.wikipedia.org/wiki/Cubic_Hermite_spline
  18. function curve(p:Array, res:Number=.05):void{
  19.     var px:Number = 0;
  20.     var py:Number = 0;
  21.     var pIter:int = p.length - 1;
  22.     var m:Array = [];
  23.     m[0] = tangent(p[1], p[0]);
  24.     for (var i:int = 1; i<pIter; i++){
  25.         m[i] = tangent(p[i + 1], p[i - 1]);
  26.     }
  27.     m[pIter] = tangent(p[pIter], p[pIter - 1]);
  28.     for (var t:Number = 0; t <1; t+=res){
  29.          var t_2:Number = t * t;
  30.          var _1_t:Number = 1 - t;
  31.          var _2t:Number = 2 * t;
  32.          var h00:Number =  (1 + _2t) * (_1_t) * (_1_t);
  33.          var h10:Number =  t  * (_1_t) * (_1_t);
  34.          var h01:Number =  t_2 * (3 - _2t);
  35.          var h11:Number =  t_2 * (t - 1);
  36.          for (var k:int = 0; k <pIter; k++){
  37.              var k1:int = k + 1;
  38.              var pk:Sprite = p[k];
  39.              var pk1:Sprite = p[k1];
  40.              var mk:Point = m[k];
  41.              var mk1:Point = m[k1];
  42.            
  43.              px = h00 * pk.x + h10 * mk.x + h01 * pk1.x + h11 * mk1.x;
  44.              py = h00 * pk.y + h10 * mk.y + h01 * pk1.y + h11 * mk1.y;
  45.              if (k == 0){
  46.                 graphics.moveTo(px, py);
  47.              }else{
  48.                 graphics.lineTo(px, py);
  49.              }
  50.              
  51.             // canvas.setPixel(px, py, 0xFFFFFF);
  52.          }
  53.     }
  54. }
  55. // draggable dot
  56. function dot(xp:Number, yp:Number, col:uint = 0xFF0000, rad:Number=4):Sprite {
  57.     var s:Sprite = Sprite(addChild(new Sprite));
  58.     s.x = xp;
  59.     s.y = yp;
  60.  
  61.     with(s.graphics) beginFill(col), drawCircle(0,0,rad);
  62.     s.buttonMode = true;
  63.     s.addEventListener(MouseEvent.MOUSE_DOWN, onDrag);
  64.     return s;
  65. }
  66. function onDrag(evt:MouseEvent):void {
  67.     evt.currentTarget.startDrag()
  68. }
  69. stage.addEventListener(MouseEvent.MOUSE_UP, onUp);
  70. stage.addEventListener(MouseEvent.MOUSE_DOWN,onDown);
  71. function onDown(evt:MouseEvent):void{
  72.       dotsVisible(false);
  73. }
  74. function onUp(evt:MouseEvent):void{
  75.     stopDrag();
  76.     dotsVisible(true);
  77. }
  78.  
  79. function dotsVisible(bool:Boolean):void{
  80.     for (var i:int = 0; i<pnts.length; i++){
  81.       pnts[i].visible = bool;
  82.      }
  83. }


You can see the swf over at wonderfl.

Posted in Uncategorized | 4 Comments

Color Words Motion Capture

By Zevan | March 20, 2010

We're still working on this long term project for medialab prado in madrid. Here is a camera test from today. It uses frame differencing and places names of colors on the areas of motion.


Click here to view the swf file... make sure to move around a bit in front of your web-cam.

Posted in Announcements, misc | Tagged , , , | 2 Comments

Connect The Dots E8

By Zevan | March 19, 2010
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width = 500, height = 500)]
  2. const TWO_PI:Number = Math.PI * 2;
  3. var centerX:Number = stage.stageWidth / 2;
  4. var centerY:Number = stage.stageHeight / 2;
  5. addEventListener(Event.ENTER_FRAME, onLoop);
  6. function onLoop(evt:Event):void{
  7.     // data
  8.     var points:Array = [];
  9.     var i:int = 0;
  10.     var pointNum : int = Math.max(2,int(mouseX / 12))
  11.    
  12.     var radius:Number = 200;
  13.     var step:Number = TWO_PI / pointNum;
  14.     var theta:Number = step / 2;
  15.     for (i = 0; i<pointNum; i++){
  16.         var xp:Number = centerX + radius * Math.cos(theta);
  17.         var yp:Number = centerY + radius * Math.sin(theta);
  18.         points[i] = new Point(xp, yp);
  19.         theta += step;
  20.     }
  21.     // render
  22.     graphics.clear();
  23.     graphics.lineStyle(0,0);
  24.     for ( i = 0; i<pointNum; i++){
  25.      var a:Point = points[i];
  26.      for (var j:int = 0; j<pointNum; j++){
  27.         var b:Point = points[j];
  28.         if (a != b){
  29.            graphics.drawCircle(a.x, a.y, 10);
  30.            graphics.moveTo(a.x, a.y);
  31.            graphics.lineTo(b.x, b.y);
  32.         }
  33.      }
  34.    }
  35. }

I've been using this geometric shape for lots of different things recently. Including during consulting gigs as a helpful visualization. Just move your mouse left and right... I particularly like the simpler forms you get by moving your mouse to the left (triangles squares and simple polygons):

While not entirely related this wikipedia article is interesting.

[EDIT : Thanks to martin for reminding me that I can do away with the if statement here in the above code ]

CLICK HERE TO COPY
Actionscript:
  1. graphics.clear();
  2. graphics.lineStyle(0,0);
  3. for (i = 0; i<pointNum; i++) {
  4.     var a:Point=points[i];
  5.     for (var j:int = i+1; j<pointNum; j++) {
  6.         var b:Point=points[j];
  7.         graphics.drawCircle(a.x, a.y, 10);
  8.         graphics.moveTo(a.x, a.y);
  9.         graphics.lineTo(b.x, b.y);
  10.     }
  11. }
  12. graphics.drawCircle(a.x, a.y, 10);

I implemented that change over at wonderfl and it works nicely

Posted in Graphics, Math, misc | Tagged , , | 4 Comments

Nonsense Clocks

By Zevan | March 15, 2010
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width = 500, height=500, backgroundColor=0x000000)]
  2.  
  3. var clockNum:int = 100;
  4. var clocks:Vector.<Function> = new Vector.<Function>(clockNum, true);
  5.  
  6. var clockContainer:Sprite = Sprite(addChild(new Sprite()));
  7. clockContainer.x = stage.stageWidth / 2;
  8. clockContainer.y = stage.stageHeight / 2;
  9. buildClocks();
  10. runClocks();
  11.  
  12. function buildClocks():void{
  13.     for (var i:int = 0; i<clockNum; i++){
  14.         var theta:Number = Math.random() * Math.PI * 2;
  15.         var radius:Number = Math.random() * 200;
  16.         var xp:Number = radius * Math.cos(theta);
  17.         var yp:Number = radius * Math.sin(theta);
  18.         clocks[i] = makeClock(xp,yp,Math.random() * Math.PI * 2);
  19.     }
  20. }
  21. function runClocks():void{
  22.     addEventListener(Event.ENTER_FRAME, onRunClocks);
  23. }
  24. function onRunClocks(evt:Event):void{
  25.     for (var i:int = 0; i<clockNum; i++){
  26.         clocks[i]();
  27.     }
  28.     clockContainer.rotationX = clockContainer.mouseY / 30;
  29.     clockContainer.rotationY = -clockContainer.mouseX / 30;
  30. }
  31. function makeClock(x:Number, y:Number, time:Number=0):Function{
  32.     var radius:Number = Math.random() * 20 + 5;
  33.     var border:Number = radius * 0.2;
  34.     var smallRadius:Number = radius - radius * 0.3;
  35.    
  36.     var clock:Sprite = Sprite(clockContainer.addChild(new Sprite()));
  37.     clock.x = x;
  38.     clock.y = y;
  39.     clock.z = 100 - Math.random() * 200;
  40.     clock.rotationX = Math.random() * 40 - 20;
  41.     clock.rotationY = Math.random() * 40 - 20;
  42.     clock.rotationZ = Math.random() * 360;
  43.     return function():void{
  44.         with (clock.graphics){
  45.             clear();
  46.             lineStyle(1,0xFFFFFF);
  47.             drawCircle(0,0,radius + border);
  48.             var xp:Number = smallRadius * Math.cos(time/2);
  49.             var yp:Number = smallRadius * Math.sin(time/2);
  50.             moveTo(0,0);
  51.             lineTo(xp, yp);
  52.             xp = radius * Math.cos(time);
  53.             yp = radius * Math.sin(time);
  54.             moveTo(0,0);
  55.             lineTo(xp, yp);
  56.         }
  57.         time+=0.1;
  58.     }
  59. }


You can go check the swf out at wonderfl.net...

Posted in 3D, Graphics, misc, motion | Tagged , , | 3 Comments