Tag Archives: actionscript

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...

Posted in BitmapData, Data Structures, misc, motion, pixel manipulation | Also tagged , | 1 Comment

Three Color Triangle

Actionscript:
  1. /*
  2. *       Petri Leskinen, Finland
  3. *       25 October 2009
  4. *       pixelero.wordpress.com
  5. *
  6. *       Actionscript 3.0, Flash CS3, Flash Player 10
  7. *
  8. *       threeColorTriangle
  9. *       draws a triangle with a gradient fill of three colors for each vertex
  10. *       using graphics.drawTriangles and a BitmapData of size 2x2
  11. */
  12. function threeColorTriangle(
  13.       point0:Point, color0:uint,
  14.       point1:Point, color1:uint,
  15.       point2:Point, color2:uint):void {
  16.  
  17.       //      create a  bitmap of size 2x2 pixels
  18.       var bmd:BitmapData = new BitmapData(2,2,true);
  19.       //      copy colors to bitmap
  20.       //      the fourth color is average of color1 and color2
  21.       bmd.setVector(bmd.rect,
  22.               Vector.<uint>([color0,color1,color2,
  23.                                          (color1+color2)>>1
  24.                                          ]));
  25.  
  26.       //      draw triangle
  27.       this.graphics.beginBitmapFill(bmd,null,false,true /* =smooth */ );
  28.       this.graphics.drawTriangles(
  29.               // x,y -coordinates
  30.               Vector.<Number>([
  31.                       point0.x,point0.y,
  32.                       point1.x,point1.y,
  33.                       point2.x,point2.y]),
  34.               // indices
  35.               Vector.<int>([0,1,2]),
  36.               // texture coordinates
  37.               Vector.<Number>([0,0, 1,0, 0,1])
  38.               );
  39. }
  40.  
  41.  
  42. // demo, let's draw some of these on the stage
  43. randomize();
  44. function randomize():void {
  45.       this.graphics.clear();
  46.  
  47.       for (var i:int = 0;i<128;i++) {
  48.               //      pick some random colors
  49.               var color0:uint = 0xFFFFFFFF;
  50.               var color1:uint = 0xFFFFFF*Math.random() | 0xFF000000;
  51.               var color2:uint = 0xFFFFFF*Math.random() | 0xFF000000;
  52.  
  53.               //      random points
  54. var point0:Point = new Point(Math.random()*stage.stageWidth,
  55.             Math.random()*stage.stageHeight);
  56. var point1:Point = new Point(point0.x+200*(Math.random()-Math.random()),
  57.             point0.y+200*(Math.random()-Math.random()));
  58. var point2:Point = new Point(point0.x+200*(Math.random()-Math.random()),
  59.             point0.y+200*(Math.random()-Math.random()));
  60.  
  61.         threeColorTriangle(point0, color0, point1, color1, point2,  color2);
  62.       }
  63. }

This snippet is by Petri Leskinen (pixelero). It draws a triangle with a gradient fill of three colors for each vertex using Graphics.drawTriangles and a BitmapData of size 2x2. This is the simplest case, it can easily be extended to four colors or maybe to use a larger 3x3, 4x4 etc... bitmap.

Here's a still...

Posted in Graphics, Vector | Also tagged , , | 5 Comments

Triangular Numbers

Actionscript:
  1. [SWF(width = 500, height = 500)]
  2.  
  3. var txt:TextField = TextField(addChild(new TextField()));
  4. txt.defaultTextFormat = new TextFormat("_sans", 4);
  5. txt.width = stage.stageWidth;
  6. txt.height = stage.stageHeight+4;
  7. txt.z = -1;
  8. txt.x = stage.stageWidth
  9. txt.rotation = 90;
  10. var count:int = 0;
  11. addEventListener(Event.ENTER_FRAME, onLoop);
  12. function onLoop(evt:Event):void{
  13.      count++;
  14.      txt.appendText(triangular(count).toString(2) + "\n");
  15.      txt.scrollV= txt.maxScrollV;
  16. }
  17. function triangular(n:int):int{
  18.        return (n * (n + 1)) / 2;
  19. }

Calculate some triangular numbers... (n * (n + 1)) / 2....

Check out the swf on wonderfl

Posted in Math, misc | Also tagged , | Leave a 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. }

Posted in Graphics, Math, Vector, misc, motion, pixel manipulation | Also tagged , , | 5 Comments