Category Archives: pixel manipulation

Frame Differencing

Actionscript:
  1. [SWF(width = 800, height= 600)]
  2. var sw:Number = 800;
  3. var sh:Number = 600;
  4. var pixelNum:int = sw * sh;
  5. var blurAmount:Number = 10;
  6. var pnt:Point = new Point(0,0);
  7. var rect:Rectangle = new Rectangle(0,0,sw,sh);
  8.  
  9. var canvas:BitmapData = new BitmapData(sw, sh, false, 0x000000);
  10. var buffer:BitmapData = new BitmapData(sw, sh, false, 0x000000);
  11. var feed  :BitmapData = new BitmapData(sw, sh, false, 0x000000);
  12. var prev  :BitmapData = new BitmapData(sw, sh, false, 0x000000);
  13.  
  14. var frame:Bitmap = new Bitmap(canvas, "auto", true);
  15. addChild(frame);
  16.  
  17. var cam:Camera =  Camera.getCamera();
  18. cam.setMode(sw,sh,12);
  19. var video:Video = new Video(sw, sh);
  20. video.attachCamera(cam);
  21.  
  22. cam.addEventListener(ActivityEvent.ACTIVITY, onActivityStart);
  23.  
  24. function onActivityStart(evt:ActivityEvent):void {
  25.     addEventListener(Event.ENTER_FRAME, onRun);
  26.     cam.removeEventListener(ActivityEvent.ACTIVITY, onActivityStart);
  27. }
  28.  
  29. function onRun(evt:Event):void{
  30.     buffer.draw(video);
  31.     feed.copyPixels(buffer, rect, pnt);
  32.     buffer.draw(prev, null, null, BlendMode.DIFFERENCE);
  33.     prev.draw(video);
  34.     canvas.copyPixels(buffer, rect, pnt);
  35. }

This snippet shows a simple method to do frame differencing with a web cam. This is useful for detecting which areas of the screen have change from frame to frame. This post assumes you pretty much know what frame differencing is.


You can view an swf file here:

This is one of those things I do a good deal but never wrapped up into a library... it's easy (for me at least) to forget exactly how to set it up from scratch.

I added an extra buffer because it's pretty common that you'll want to other things aside from just frame differencing alone, so it's nice to have it all wrapped up in a buffer BitmapData that you can use elsewhere. If speed is a real concern, you can do away with the buffer and just use the canvas instead - depending on what kind of analysis your doing on the frame differenced image it may be trickier without the buffer.

Also posted in BitmapData, Video, graphics algorithms | Tagged , , | 5 Comments

~20,000 Rollovers

Actionscript:
  1. [SWF(width = 500, height = 500, frameRate = 30)]
  2.  
  3. var canvas:BitmapData = new BitmapData(stage.stageWidth,stage.stageHeight,false, 0xFFFFFF);
  4.  
  5. var indexCanvas:BitmapData = new BitmapData(stage.stage.stageWidth, stage.stageHeight, false,
  6.                                             0xFFFFFF);
  7. addChild(new Bitmap(canvas));
  8.  
  9. var s:Shape = new Shape();
  10.  
  11. var lineData:Array = [];
  12. var dataIndex:int = 0;
  13.  
  14. trace(0xFFFFFF - 1)
  15. var totalLines:int = 20000;
  16. var iterations:int = 9;
  17. var linesPerIter:int = totalLines / iterations;
  18.  
  19. var xp:int = stage.stageWidth / 2;
  20. var yp:int = stage.stageHeight / 2;
  21.  
  22. var stepAmt:Number = 60;
  23. var halfStepAmt:Number = stepAmt / 2;
  24.  
  25. addEventListener(Event.ENTER_FRAME, onDraw);
  26. function onDraw(evt:Event):void {
  27.      if (lineData.length <totalLines){
  28.         generateData(linesPerIter);
  29.      }else{
  30.         stage.quality = "high";
  31.         addChild(s);
  32.         s.x = 0;
  33.         s.y = 0;
  34.          
  35.         removeEventListener(Event.ENTER_FRAME, onDraw);
  36.         addEventListener(Event.ENTER_FRAME, onRun);
  37.      }
  38. }
  39.  
  40. function onRun(evt:Event):void {
  41.    var currentIndex:int = indexCanvas.getPixel(mouseX, mouseY);
  42.    var currentLine:Array = lineData[currentIndex];
  43.    
  44.    s.graphics.clear();
  45.    if (currentIndex != 0xFFFFFF){
  46.           s.graphics.lineStyle(3, 0xFF0000);
  47.           s.graphics.moveTo(currentLine[0], currentLine[1]);
  48.           s.graphics.lineTo(currentLine[2], currentLine[3]);  
  49.    }
  50. }
  51.  
  52. function generateData(num:int):void{
  53.     var rxA:int, rxB:int, ryA:int, ryB:int;
  54.     var g:Graphics = s.graphics;
  55.     for (var i:int = 0; i<num; i++){
  56.         rxA = xp;
  57.         ryA = yp;
  58.        
  59.         xp += Math.round(Math.random() * stepAmt) - halfStepAmt;
  60.         yp += Math.round(Math.random() * stepAmt) - halfStepAmt;
  61.        
  62.         if (xp> stage.stageWidth){
  63.             xp = stage.stageWidth - halfStepAmt;
  64.         }else
  65.         if (xp <0){
  66.             xp = halfStepAmt;
  67.         }
  68.         if (yp> stage.stageHeight){
  69.             yp = stage.stageHeight - halfStepAmt;
  70.         }else
  71.         if (yp <0){
  72.             yp = halfStepAmt;
  73.         }
  74.        
  75.         rxB = xp;
  76.         ryB = yp;
  77.          
  78.         lineData[dataIndex] = [rxA, ryA, rxB, ryB];            
  79.         s.x = rxA;
  80.         s.y = ryA;
  81.         var endX:Number = rxB - rxA;
  82.         var endY:Number = ryB - ryA;
  83.         var m:Matrix = s.transform.matrix;
  84.         g.clear();
  85.         g.lineStyle(1, 0x000000, 0.3);
  86.  
  87.         g.lineTo(endX, endY);
  88.         stage.quality = "high";
  89.         canvas.draw(s, m);
  90.        
  91.         g.clear();
  92.         g.lineStyle(3, dataIndex);
  93.        
  94.         g.lineTo(endX, endY);
  95.         stage.quality = "low";
  96.         indexCanvas.draw(s, m);
  97.        
  98.         dataIndex++
  99.     }
  100. }

I'm working on a data visualization that contains a long path made up of approximately one million points. There is some information associated with every two sets of coordinates that needs to be displayed when the user rolls their mouse over any part of the line.

I took a little time to think about the best way to do this and came up with a few techniques. The first one I tried seems to work nicely - this snippet is the proof of concept for that first technique. I tested this snippet with 1,000,000 xy coordinates and it works nicely. It takes a little while to draw though, so for the purposes of this demo I've just included 20,000 coordinates.

Have a look at the swf over at wonderfl.net

The way this works is by drawing lines to two different BitmapData instances. I draw anti-aliased slightly transparent lines to a BitmapData instance called "canvas" (this is added to the display list) - I then draw aliased lines to a BitmapData called "indexCanvas" (this is never added to the display list) - each aliased line uses an incremental value for its color - this incremental value is also the index for a two dimensional array containing the coordinate information for the aliased line. I use getPixel() on the "indexCanvas" and use the return value as the index for the 2D array. The data from the 2D array is used to draw a red line with the graphics class. This technique enables you to have many many rollovers and all you ever have to do is call getPixel() and use the returned color value to look up info about what you're mouse is touching.

There are a few cool ways this could be repurposed and this is really only one solution to the problem of having many many things that you need to be able to rollover... there are others that don't use BitmapData at all... I may write those up in the next couple of days.

Also posted in BitmapData, Data Structures, UI, arrays, display list, graphics algorithms, matrix, misc, return values | Tagged , , | 2 Comments

QuickBox2D 1.1 (2 major bug fixes)

Since the release of QuickBox2D 1.0 two bugs were discovered by numerous developers. The first bug was the inability to properly destroy group objects. The second bug was a small memory leak that caused most QuickObjects to remain in memory. Both of these bugs are now resolved.

Download QuickBox2D 1.1

Testing the memory leak. In QuickBox2D 1.0 if you created and destroyed 100s of rigid bodies, the ram would very slowly rise... Sometimes it would get garbage collected, but the memory would never fully be released. I created a simple test to make sure this is fixed in 1.1:

Actionscript:
  1. import com.actionsnippet.qbox.*;
  2.  
  3. var sim:QuickBox2D = new QuickBox2D(this, {debug:false});
  4.  
  5. sim.createStageWalls();
  6.  
  7. var levelParts:Array = [];
  8. const TWO_PI:Number = Math.PI * 2;
  9.  
  10. // destroys and then creates a bunch of rigid bodies
  11. // called every second
  12. buildRandomLevel();
  13. setInterval(buildRandomLevel, 1000);
  14.  
  15. var txt:TextField = TextField(addChild(new TextField()));
  16. txt.x = txt.y = 30;
  17. txt.backgroundColor = 0xFFFFFF;
  18. sim.start();
  19.  
  20. // display amount of ram used, to make sure garbage collection is working
  21. sim.addEventListener(QuickBox2D.STEP, onStep);
  22. function onStep(evt:Event):void{
  23.     txt.text = (System.totalMemory / 100000).toFixed(2) + "mb";
  24. }
  25.  
  26. function buildRandomLevel():void{
  27.     // destroy all rigid bodies
  28.     for (var i:int = 0; i<levelParts.length; i++){
  29.         levelParts[i].destroy();
  30.     }
  31.     levelParts = [];
  32.     // create a bunch of circles and boxes
  33.     for (i = 0; i<16; i++){
  34.         var rad:Number = 0.4 ;
  35.         levelParts.push(sim.addCircle({x:1 + i * rad * 4, y : 2, radius:rad - Math.random()*0.3}));
  36.        
  37.         var rot:Number = Math.random() * TWO_PI;
  38.         levelParts.push(sim.addBox({x:4+Math.random() * i * 2, y:4+Math.random()*i,
  39.                     width:3, height:0.25, angle:rot, density:0}));
  40.     }
  41. }

This snippet creates and destroys a bunch of rigid bodies again and again.... On my macbook 2.6 Ghz intel core duo... the ram runs between 79mb and 112mb. I let it run for 40 minutes and this did not change - it always eventually returned down to 79mb.


Have a look at the swf...

Thanks to all the people who gave feedback that lead to the discover of these bugs.

Also posted in Box2D, QuickBox2D, motion | Tagged , , , | 25 Comments

BitmapData Frame Animation (w/ linked list)

Actionscript:
  1. [SWF(width = 100, height = 100)]
  2. var circle:Shape = new Shape();
  3. with(circle.graphics) beginFill(0x000000), drawCircle(20,20,20);
  4.  
  5. var currFrame:Frame;
  6.  
  7. // populate the linked list
  8. generateAnimation();
  9.  
  10. var canvas:BitmapData = new BitmapData(stage.stageWidth,stage.stageHeight,false, 0x000000);
  11. addChild(new Bitmap(canvas));
  12. var loc:Point = new Point(20, 20);
  13.  
  14. addEventListener(Event.ENTER_FRAME, onLoop);
  15. function onLoop(evt:Event):void {
  16.     // clear the canvas
  17.     canvas.fillRect(canvas.rect, 0x000000);
  18.     // draw the current frame
  19.     canvas.copyPixels(currFrame.bitmap, currFrame.bitmap.rect, loc, null, null, true);
  20.     // get the next frame of the animation
  21.     currFrame = currFrame.next;
  22. }
  23.  
  24. // generate and capture 40 bitmaps by altering the colorTransform of the circle shape
  25. function generateAnimation():void{
  26.     var channel:uint = 0;
  27.     var ct:ColorTransform = new ColorTransform();
  28.     var increase:Boolean = true;
  29.     var firstFrame:Frame;
  30.     var pFrame:Frame;
  31.     for (var i:int = 0; i<40; i++){
  32.         if (increase){
  33.            channel += 10;
  34.            if (channel == 200){
  35.               increase = false;  
  36.            }
  37.         }else{
  38.            channel -= 10;
  39.         }
  40.         ct.color = channel <<16 | channel <<8 | channel;
  41.         circle.transform.colorTransform = ct;
  42.         // populate linked list
  43.         currFrame = capture(circle);
  44.         if (pFrame){
  45.            pFrame.next = currFrame;
  46.         }
  47.         if (i == 0){
  48.            firstFrame = currFrame;
  49.         }
  50.         pFrame = currFrame;
  51.     }
  52.     // close the list
  53.     currFrame.next = firstFrame;
  54.     currFrame = firstFrame;
  55. }
  56.  
  57. // create the Frame instance and draw the circle to it
  58. // preserving the colorTransform information
  59. function capture(target:Shape):Frame{
  60.     var frame:Frame = new Frame();
  61.     frame.bitmap = new BitmapData(target.width, target.height, true, 0x00000000);
  62.     frame.bitmap.draw(target, null, target.transform.colorTransform);
  63.     return frame;
  64. }

Requires this little Frame class

Actionscript:
  1. package {
  2.     import flash.display.*;
  3.     final public class Frame{
  4.         public var bitmap:BitmapData;
  5.         public var next:Frame;
  6.     }
  7. }

This is a small test I did today to see how easy it would be to use a circular linked list to loop an animation of bitmaps. I did this because I was thinking about using some animated sprites in conjunction with Utils3D.projectVectors() to do an orthographic 3D demo with lots of animating sprites. In the past I've had up to 7,000 animated sprites running nicely using arrays and copyPixels... figured it would be interesting to try and do the same with a circular linked list.

When compiled, this test simply draws a circle that fades from black to gray and back again... Pretty boring, but I threw it up over at wonderfl anyway... check it out.

I recently saw a few tweets (forget who from) about using the final keyword on linked list nodes... haven't tested it myself but it's supposed to be faster...

Also posted in BitmapData, Data Structures, misc, motion | Tagged , , | 1 Comment

Flowing Leaves (optical illusion)


Saw this optical illusion today... figured I'd make a snippet to create a few variations on the illusion...

Actionscript:
  1. [SWF( backgroundColor=0x2E7999, width=780, height = 600) ]
  2.  
  3. var leafNum:Number = 375;
  4. var spacing:Number = 12;
  5. var cols:Number = 25;
  6. var hh:Number = stage.stageHeight / 2;
  7. var hw:Number = stage.stageWidth / 2;
  8.  
  9. for (var i:Number = 0; i<leafNum; i++){
  10.     var leaf:Shape = makeLeaf();
  11.     leaf.scaleX = leaf.scaleY = 0.25;
  12.     leaf.rotation = 90;
  13.     leaf.x = 50 + (i % cols) * (leaf.width + spacing);
  14.     leaf.y = 40 + int(i / cols) * (leaf.height + spacing);
  15.     var dx:Number = leaf.x - hw;
  16.     var dy:Number = leaf.y - hh;
  17.     leaf.rotation = Math.sqrt(dx * dx + dy * dy);
  18. }
  19.  
  20. function makeLeaf():Shape{
  21.     var leaf:Shape = Shape(addChild(new Shape()));
  22.     leaf.graphics.beginFill(0x9DC4D4);
  23.     scaleYcircle(leaf.graphics, 50, .65, false);
  24.     leaf.graphics.endFill();
  25.     leaf.graphics.lineStyle(2, 0x003366, 1, false, "none", CapsStyle.SQUARE, JointStyle.MITER);
  26.     scaleYcircle(leaf.graphics, 50, .65);
  27.     leaf.graphics.lineStyle(2, 0xFFFFFF, 1, false, "none", CapsStyle.SQUARE, JointStyle.MITER);
  28.     scaleYcircle(leaf.graphics, -50, .65);
  29.     return leaf;
  30. }
  31.  
  32.  
  33. // original circle function by senocular (www.senocular.com) from here http://www.actionscript.org/forums/showthread.php3?s=&threadid=30328
  34. // circle that can be scaled on the y axis
  35. function scaleYcircle(g:Graphics, r:Number, s:Number = 1, isHalf:Boolean=true):void {
  36.      
  37.     var c1:Number = r * (Math.SQRT2 - 1);
  38.     var c2:Number = r * Math.SQRT2 / 2;
  39.     var rs:Number = r * s, c1s:Number = c1 * s, c2s:Number = c2 * s;
  40.     var x_r:Number =  -r, y_r:Number = -rs, x_c2:Number =  -c2;
  41.     var y_c2:Number =  -c2s, x_c1:Number =  -c1, y_c1:Number =  -c1s
  42.     g.moveTo(r, 0), g.curveTo(r, c1s, c2, c2s);
  43.     g.curveTo(c1, rs, 0, rs), g.curveTo(x_c1,rs, x_c2, c2s);
  44.     g.curveTo(x_r, c1s, x_r, 0);
  45.     if (!isHalf){
  46.      g.curveTo(x_r,y_c1,x_c2,y_c2);
  47.      g.curveTo(x_c1,y_r,0,y_r), g.curveTo(c1,y_r,c2,y_c2);
  48.      g.curveTo(r,y_c1,r,0);
  49.     }
  50. }

Also posted in Graphics, Math, Vector, misc, motion | Tagged , , , | 5 Comments

Sierpiński Glitch Texture #3

Actionscript:
  1. [SWF(frameRate=60, backgroundColor=0x000000, width=500, height=500)]
  2.  
  3. var canvas:BitmapData = new BitmapData(500,500,false, 0x000000);
  4. addChild(new Bitmap(canvas));
  5. var clone:BitmapData = new BitmapData(500,500,false, 0x000000);
  6. var canvasRect:Rectangle = canvas.rect;
  7. var w:int = canvas.width;
  8. var w2:Number = 1/w;
  9. var w10:Number = 1/(w * 80);
  10. var convert:Number = Math.PI/180;
  11. var size:int = canvas.width * canvas.height;
  12. var pix:Vector.<uint> = new Vector.<uint>(size, true);
  13. var m:Matrix = new Matrix();
  14. m.scale(1,-1);
  15. m.translate(0,canvas.height);
  16. var sin:Number = 0, cos:Number = 0;
  17. var dx:Number = 0, dy:Number = 0;
  18. var pnt:Point = new Point();
  19. var blur:BlurFilter = new BlurFilter(10,10,1);
  20. addEventListener(Event.ENTER_FRAME, onLoop);
  21. function onLoop(evt:Event):void {
  22.     canvas.lock();
  23.     dx +=  (mouseX * 10 - 3000 - dx) / 8;
  24.     dy +=  (mouseY * 4 - dy) / 8;
  25.     for (var i:int = 0; i<size; i++){
  26.         var xp:int = i % w;
  27.         var yp:int = int(i * w2);
  28.         var xp2:int = xp <<1;
  29.         var t:Number;
  30.         t = ((yp|(xp + yp * 0.1)) * (xp + dx) *w10) % 6.14687;
  31.         //compute sine
  32.         // technique from http://lab.polygonal.de/2007/07/18/fast-and-accurate-sinecosine-approximation/
  33.         // by Michael Baczynski
  34.         if (t<0) {
  35.             sin=1.27323954*t+.405284735*t*t;
  36.         } else {
  37.             sin=1.27323954*t-0.405284735*t*t;
  38.         }
  39.         // compute cosine
  40.         t = (xp2|(yp+xp*0.1) + dy) * convert % 6.28;
  41.         t+=1.57079632;
  42.         if (t>3.14159265) {
  43.             t-=6.28318531;
  44.         }
  45.         if (t<0) {
  46.             cos=1.27323954*t+0.405284735*t*t;
  47.         } else {
  48.             cos=1.27323954*t-0.405284735*t*t;
  49.         }
  50.         var c1:int = 31 * (sin - cos);
  51.         if (c1 <0) c1 = 256 - c1;
  52.         c1 = (c1 <<4 | c1) ;
  53.         pix[i] = c1 <<16 | c1 <<8 | c1;
  54.     }
  55.     canvas.setVector(canvasRect, pix);
  56.     clone.copyPixels(canvas, canvasRect, pnt);
  57.     canvas.draw(clone, m, null, BlendMode.SUBTRACT);
  58.     clone.copyPixels(canvas, canvasRect, pnt);
  59.     clone.applyFilter(clone, canvasRect, pnt, blur);
  60.     canvas.draw(clone, null, null, BlendMode.SCREEN);
  61.     canvas.unlock();
  62. }

Decided to do a grayscale version ... also rendered it out large and posted it on flickr...

Check out the swf...


Check out the large flickr version...

Also posted in BitmapData, Operators, Vector | Tagged , , | 2 Comments

Sierpiński Glitch Texture #2

Actionscript:
  1. [SWF(frameRate=60, backgroundColor=0x000000, width=500, height=500)]
  2. var canvas:BitmapData = new BitmapData(500,500,false, 0x000000);
  3. addChild(new Bitmap(canvas));
  4. var clone:BitmapData = new BitmapData(500,500,false, 0x000000);
  5. var canvasRect:Rectangle = canvas.rect;
  6. var w:int = canvas.width;
  7. var w2:Number = 1/w;
  8. var w10:Number = 1/(w * 80);
  9. var convert:Number = Math.PI/180;
  10. var size:int = canvas.width * canvas.height;
  11. var pix:Vector.<uint> = new Vector.<uint>(size, true);
  12. var gray:ColorMatrixFilter = new ColorMatrixFilter([1, 0.55, 0.55, 0,0,0.55, 0.9, 0.55, 0,0,0.55, 0.55, 0.550,0, 0,0,0,1,0]);
  13. var m:Matrix = new Matrix();
  14. m.scale(1,-1);
  15. m.translate(0,canvas.height);
  16. var sin:Number = 0, cos:Number = 0;
  17. var dx:Number = 0, dy:Number = 0;
  18. var pnt:Point = new Point();
  19. var blur:BlurFilter = new BlurFilter(10,10,1);
  20. addEventListener(Event.ENTER_FRAME, onLoop);
  21. function onLoop(evt:Event):void {
  22.     canvas.lock();
  23.     dx += (mouseX * 10 - 3000 - dx) / 8;
  24.     dy += (mouseY * 4 - dy) / 8;
  25.     for (var i:int = 0; i<size; i++){
  26.         var xp:int = i % w;
  27.         var yp:int = int(i * w2);
  28.         var xp2:int = xp <<1;
  29.         var t:Number;
  30.         t = ((yp|(xp + yp)) * (xp + dx) *w10) % 6.14687;
  31.         //compute sine
  32.         // technique from http://lab.polygonal.de/2007/07/18/fast-and-accurate-sinecosine-approximation/
  33.         // by Michael Baczynski
  34.         if (t<0) {
  35.             sin=1.27323954*t+.405284735*t*t;
  36.         } else {
  37.             sin=1.27323954*t-0.405284735*t*t;
  38.         }
  39.         // compute cosine
  40.         t = (xp2|(yp+xp/dx) + dy) * convert % 6.28;
  41.         t+=1.57079632;
  42.         if (t>3.14159265) {
  43.             t-=6.28318531;
  44.         }
  45.         if (t<0) {
  46.             cos=1.27323954*t+0.405284735*t*t;
  47.         } else {
  48.             cos=1.27323954*t-0.405284735*t*t;
  49.         }
  50.         var c1:int = 31 * (sin - cos);
  51.         if (c1 <0) c1 = 256 - c1;
  52.         c1 = (c1>>1  | c1) ;
  53.         pix[i] = c1 <<17 | c1 <<8 | c1;
  54.     }
  55.     canvas.setVector(canvasRect, pix);
  56.     clone.copyPixels(canvas, canvasRect, pnt);
  57.     canvas.draw(clone, m, null, BlendMode.SUBTRACT);
  58.     clone.copyPixels(canvas, canvasRect, pnt);
  59.     clone.applyFilter(clone, canvasRect, pnt, blur);
  60.    
  61.     canvas.draw(clone, null, null, BlendMode.LIGHTEN);
  62.     canvas.applyFilter(canvas, canvasRect, pnt, gray);
  63.     canvas.unlock();
  64. }

More texture experimentation...

Have a look at the swf over at wonderfl.net...

Also posted in BitmapData, Operators, Vector | Tagged , , | Leave a comment

Interesting Texture #3 (animated)

Actionscript:
  1. [SWF(frameRate=60, backgroundColor=0x000000, width=500, height=500)]
  2. var canvas:BitmapData = new BitmapData(500,500,false, 0x000000);
  3. addChild(new Bitmap(canvas));
  4. var clone:BitmapData = new BitmapData(500,500,false, 0x000000);
  5. var canvasRect:Rectangle = canvas.rect;
  6. var w:int = canvas.width;
  7. var w2:Number = 1/w;
  8. var w10:Number = 1/(w * 80);
  9. var convert:Number = Math.PI/180;
  10. var size:int = canvas.width * canvas.height;
  11. var pix:Vector.<uint> = new Vector.<uint>(size, true);
  12. var gray:ColorMatrixFilter = new ColorMatrixFilter([1, 0.55, 0.55, 0,0,0.55, 0.9, 0.55, 0,0,0.55, 0.55, 0.550,0, 0,0,0,1,0]);
  13. var m:Matrix = new Matrix();
  14. m.scale(1,-1);
  15. m.translate(0,canvas.height);
  16. var sin:Number = 0, cos:Number = 0;
  17. var dx:Number = 0, dy:Number = 0;
  18. var pnt:Point = new Point();
  19. var blur:BlurFilter = new BlurFilter(10,10,1);
  20. addEventListener(Event.ENTER_FRAME, onLoop);
  21. function onLoop(evt:Event):void {
  22.     canvas.lock();
  23.     dx += (mouseX * 10 - 3000 - dx) / 8;
  24.     dy += (mouseY * 4 - dy) / 8;
  25.     for (var i:int = 0; i<size; i++){
  26.         var xp:int = i % w;
  27.         var yp:int = int(i * w2);
  28.         var xp2:int = xp <<1;
  29.         var t:Number = (yp * (xp2 + dx) * w10) % 3.14687;
  30.         //compute sine
  31.         // technique from http://lab.polygonal.de/2007/07/18/fast-and-accurate-sinecosine-approximation/
  32.         // by Michael Baczynski
  33.         if (t<0) {
  34.             sin=1.27323954*t+.405284735*t*t;
  35.         } else {
  36.             sin=1.27323954*t-0.405284735*t*t;
  37.         }
  38.         // compute cosine
  39.         t = (xp2 + dy) * convert % 6.28;
  40.         t+=1.57079632;
  41.         if (t>3.14159265) {
  42.             t-=6.28318531;
  43.         }
  44.         if (t<0) {
  45.             cos=1.27323954*t+0.405284735*t*t;
  46.         } else {
  47.             cos=1.27323954*t-0.405284735*t*t;
  48.         }
  49.         var c1:int = 31 * (cos - sin);
  50.         if (c1 <0) c1 = 256 - c1;
  51.         c1 = (c1 <<2 | c1) ;
  52.         pix[i] = c1 <<15 | c1 <<9 | c1;
  53.     }
  54.     canvas.setVector(canvasRect, pix);
  55.     clone.copyPixels(canvas, canvasRect, pnt);
  56.     canvas.draw(clone, m, null, BlendMode.SUBTRACT);
  57.     clone.copyPixels(canvas, canvasRect, pnt);
  58.     clone.applyFilter(clone, canvasRect, pnt, blur);
  59.     canvas.draw(clone, null, null, BlendMode.ADD);
  60.     canvas.applyFilter(canvas, canvas.rect, new Point(0,0), gray);
  61.     canvas.unlock();
  62. }

This snippet creates an interactive animated texture. Originally this texture wasn an unoptimized messy code snippet (see the original post here) - I went through and did a few optimizations to get it running in real-time and this is the result:

Check out the swf over at wonderfl.net...

Also posted in BitmapData, Vector, color | Tagged , , | Leave a comment

Interesting Texture #3

Actionscript:
  1. var canvas:BitmapData = new BitmapData(1500,1000,false, 0x000000);
  2. addChild(new Bitmap(canvas));
  3. scaleX = scaleY = .5;
  4.  
  5. var w:int = canvas.width;
  6. var w10:int = w * 80;
  7. var convert:Number = Math.PI/180;
  8. var size:int = canvas.width * canvas.height;
  9. for (var i:int = 0; i<size; i++){
  10.     var xp:int = i % w;
  11.     var yp:int = int(i / w);
  12.     var xp2:int = xp * 2;
  13.     var c1:int = (255/8) * (Math.cos(xp2 * convert) - Math.sin(yp*(xp2 + 500)/w10));
  14.     if (c1 <0) c1 = 256 - c1;
  15.     c1 = (c1 <<2 | c1) ;
  16.     canvas.setPixel(xp, yp, c1 <<15 | c1 <<9 | c1 );
  17. }
  18. var m:Matrix = new Matrix();
  19. m.scale(1,-1);
  20. m.translate(0,canvas.height);
  21. var clone:BitmapData = canvas.clone();
  22. canvas.draw(clone, m, null, BlendMode.SUBTRACT);
  23. clone.draw(canvas);
  24. clone.applyFilter(clone, clone.rect, new Point(0,0), new BlurFilter(10,10,1));
  25. canvas.draw(clone, null, null, BlendMode.ADD);
  26. var gray:ColorMatrixFilter = new ColorMatrixFilter([1, 0.55, 0.55, 0,0,0.55, 0.9, 0.55, 0,0,0.55, 0.55, 0.550,0, 0,0,0,1,0]);
  27. canvas.applyFilter(canvas, canvas.rect, new Point(0,0), gray);

Soon I'll work on a real-time variation. For now, here is one more still...

Also posted in BitmapData, setPixel | Tagged , , | Leave a comment

Interesting Texture #2

Actionscript:
  1. var canvas:BitmapData = new BitmapData(1000,1000,false, 0x000000);
  2. addChild(new Bitmap(canvas));
  3. scaleX = scaleY = .5;
  4.  
  5. var w:int = canvas.width;
  6. var w10:int = w * 40;
  7. var size:int = canvas.width * canvas.height;
  8. for (var i:int = 0; i<size; i++){
  9.     var xp:int = i % w;
  10.      
  11.     var yp:int = int(i / w);
  12.     var c1:int = (255/8) * (Math.cos(xp* Math.PI/180 * 2) + Math.sin(yp*(xp + 200)/w10));
  13.     if (c1 <0) c1 = 256 - c1;
  14.     c1 = (c1 <<1 | c1) ;
  15.     canvas.setPixel(xp, yp, c1 <<15 | c1 <<7 | c1 );
  16. }
  17. var m:Matrix = new Matrix();
  18. m.scale(1,-1);
  19. m.translate(0,canvas.height);
  20. var clone:BitmapData = canvas.clone();
  21. canvas.draw(clone, m, null, BlendMode.SUBTRACT);
  22. clone.draw(canvas);
  23. clone.applyFilter(clone, clone.rect, new Point(0,0), new BlurFilter(10,10,1));
  24. canvas.draw(clone, null, null, BlendMode.ADD);

Randomly bit shifting on this one is actually getting a good deal of millage.. I know I can easily optimize so that it works in realtime - could even be done in pixelbender... but going to play a bit more first before I optimize....

Also posted in BitmapData, misc, setPixel | Tagged , , | Leave a comment