Variable Line Resolution

By Zevan | July 7, 2009
CLICK HERE TO COPY
Actionscript:
  1. var loc:Vector.<Point> = new Vector.<Point>();
  2. var lifts:Vector.<int> = new Vector.<int>();
  3. var index:int = 0;
  4. var resolution:int = 1;
  5. var down:Boolean;
  6. stage.addEventListener(MouseEvent.MOUSE_DOWN, onDown);
  7. stage.addEventListener(MouseEvent.MOUSE_UP, onUp);
  8. stage.addEventListener(KeyboardEvent.KEY_UP, onKeyReleased);
  9. addEventListener(Event.ENTER_FRAME, onLoop);
  10. function onKeyReleased(evt:KeyboardEvent):void{
  11.     if (evt.keyCode == Keyboard.RIGHT){
  12.         resolution -= 1;
  13.         if (resolution <1) resolution = 1;
  14.     }else
  15.     if (evt.keyCode == Keyboard.LEFT){
  16.         resolution += 1;
  17.     }
  18. }
  19. function onDown(evt:MouseEvent):void{
  20.     down = true;
  21.     lifts.push(index);
  22. }
  23. function onUp(evt:MouseEvent):void{
  24.     down = false;
  25. }
  26. function onLoop(evt:Event):void {
  27.     if (down){
  28.         loc[index] = new Point(mouseX, mouseY);
  29.         index++;
  30.     }
  31.     graphics.clear();
  32.     graphics.lineStyle(0,0x000000);
  33.     var liftIndex:int = 0;
  34.     for (var i:int = 0; i<loc.length; i++){
  35.         if (liftIndex == lifts.length) liftIndex = 0;
  36.         if (i == lifts[liftIndex]){
  37.             graphics.moveTo(loc[i].x, loc[i].y);
  38.             liftIndex++;
  39.         }else{
  40.             if (i % resolution == 1 || resolution == 1){
  41.                 graphics.lineTo(loc[i].x, loc[i].y);
  42.             }
  43.         }
  44.     }
  45. }

This snippet shows a simple approach to creating variable resolution graphics.

Below is a drawing done using this snippet. The left arrow key is used to decrease resolution and the right arrow key is used to increase resolution:


Click to view swf...

Posted in Graphics, Vector | Tagged , , | 3 Comments

Utils3D.projectVectors() Lathe

By Zevan | July 6, 2009
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width = 500, height = 500, backgroundColor = 0x000000)]
  2. var halfWidth:Number = stage.stageWidth / 2;
  3. var halfHeight:Number = stage.stageHeight / 2;
  4. var loc:Vector.<Number>;
  5.  
  6. graphics.lineStyle(0, 0xFF0000);
  7. graphics.moveTo(halfWidth, 0);
  8. graphics.lineTo(halfWidth, stage.stageHeight);
  9. graphics.moveTo(0, halfHeight);
  10. graphics.lineTo(stage.stageWidth, halfHeight);
  11.  
  12. var line:Shape = Shape(addChild(new Shape()));
  13. line.x = halfWidth;
  14.  
  15. var idle:Function = function(){};
  16. var currentMode:Function = idle;
  17. stage.addEventListener(MouseEvent.MOUSE_DOWN, onDown);
  18. stage.addEventListener(MouseEvent.MOUSE_UP, onUp);
  19. addEventListener(Event.ENTER_FRAME, onLoop);
  20. function onDown(evt:MouseEvent):void{
  21.     if (contains(frame)){
  22.         removeChild(frame);
  23.         currentMode = idle;
  24.         line.graphics.clear();
  25.         return;
  26.     }
  27.     loc = new Vector.<Number>();
  28.     line.graphics.lineStyle(0,0xFFFFFF);
  29.     line.x = halfWidth
  30.     line.y = halfHeight;
  31.     line.graphics.moveTo(line.mouseX, line.mouseY);
  32.     currentMode = captureLocs;
  33.     canvas.fillRect(canvas.rect, 0x000000);
  34. }
  35. function onUp(evt:MouseEvent):void{
  36.     if (currentMode == idle) return;
  37.     setupLathe();
  38.     currentMode = showLathe;
  39. }
  40.  
  41. function onLoop(evt:Event):void{
  42.     currentMode();
  43. }
  44. function captureLocs():void{
  45.     loc.push(line.mouseX);
  46.     loc.push(line.mouseY);
  47.     loc.push(0);
  48.     line.graphics.lineTo(line.mouseX, line.mouseY);
  49. }
  50. /**
  51.  -- Lathe Stuff:
  52. */
  53. var canvas:BitmapData = new BitmapData(stage.stageWidth, stage.stageHeight,false, 0x000000);
  54. var frame:Bitmap = new Bitmap(canvas);
  55. var dx:Number=0;
  56. var dy:Number=0;
  57.  var matrix:Matrix3D = new Matrix3D();
  58. var pVerts:Vector.<Number>;
  59. var uvts:Vector.<Number>;
  60. function setupLathe():void{
  61.     addChild(frame);
  62.     pVerts =  new Vector.<Number>();
  63.     uvts = new Vector.<Number>();
  64.     var nVerts:Vector.<Number> = new Vector.<Number>();
  65.     var tVerts:Vector.<Number> = new Vector.<Number>();
  66.     matrix.identity();
  67.     var step:Number = 2;
  68.     for (var i:int = 0; i <360; i+=step){
  69.         matrix.appendRotation(step,Vector3D.Y_AXIS);
  70.         matrix.transformVectors(loc, tVerts);
  71.         nVerts = nVerts.concat(tVerts);
  72.     }
  73.     loc = nVerts.concat();
  74. }
  75. function showLathe():void{
  76.     dx += (mouseX - dx)/4;
  77.     dy += (mouseY - dy)/4;
  78.     matrix.identity();
  79.     matrix.appendRotation(dy,Vector3D.X_AXIS);
  80.     matrix.appendRotation(dx,Vector3D.Y_AXIS);
  81.     matrix.appendTranslation(halfWidth, halfHeight, 0);
  82.     Utils3D.projectVectors(matrix, loc, pVerts, uvts);
  83.     canvas.lock();
  84.     canvas.fillRect(canvas.rect, 0x000000);
  85.     var leng:int = pVerts.length;
  86.     for (var i:int = 0; i<leng; i+=2){
  87.         canvas.setPixel( pVerts[i], pVerts[i + 1], 0xFFFFFF);
  88.     }
  89.     canvas.unlock();
  90. }

This snippet allows you to create 3D lathe shapes by drawing a 2D line. This is done using Utils3D.projectVectors() and Matrix.transformVectors().

Have a look at the swf here...

Posted in 3D, BitmapData, Math, Vector, graphics algorithms, matrix, setPixel | Tagged , , | 3 Comments

FileReference.load()

By Zevan | July 5, 2009
CLICK HERE TO COPY
Actionscript:
  1. var txt:TextField = TextField(addChild(new TextField()));
  2. txt.autoSize = TextFieldAutoSize.LEFT;
  3. txt.x = txt.y = 20;
  4. txt.text = "click anywhere to load an image file...";
  5.  
  6. var fileRef:FileReference= new FileReference();
  7. stage.addEventListener(MouseEvent.MOUSE_DOWN, onDown);
  8. function onDown(evt:MouseEvent):void{
  9.     fileRef.browse([new FileFilter("Images", "*.jpg;*.gif;*.png")]);
  10.     fileRef.addEventListener(Event.SELECT, onSelected);
  11.     stage.removeEventListener(MouseEvent.MOUSE_DOWN, onDown);
  12. }
  13. function onSelected(evt:Event):void{
  14.     fileRef.addEventListener(Event.COMPLETE, onLoaded);
  15.     fileRef.load();
  16.     fileRef.removeEventListener(Event.SELECT, onSelected);
  17. }
  18. function onLoaded(evt:Event):void{
  19.     var loader:Loader = new Loader();
  20.     loader.loadBytes(evt.target.data);
  21.     addChild(loader);
  22.     fileRef.removeEventListener(Event.COMPLETE, onLoaded);
  23. }

This snippet shows how to use the FileReference.load() method to load an image into flash player RAM and display it on the stage.

Posted in external data, misc | Tagged , , | Leave a comment

Counter Function

By Zevan | July 4, 2009
CLICK HERE TO COPY
Actionscript:
  1. var counter:Function = function(count:Array):Function{
  2.     var leng:int = count.length;
  3.     var index:int = 0;
  4.     return counter = function(reset:*=""):Function{
  5.         if (reset=="reset"){
  6.             index = 0;
  7.             return counter;
  8.         }else
  9.         if (reset is Array){
  10.             count = reset;
  11.             return counter;
  12.         }
  13.         trace(count[index % leng]);
  14.         index++;
  15.         return counter;
  16.     }
  17. }
  18.  
  19. // first time it's called you pass an array
  20. trace("count through the array:");
  21. // you can optionally call trigger the counter by calling the newly
  22. // returned function
  23. counter(["a","b","c"])();
  24. counter();
  25. counter();
  26. trace("change the array:");
  27. // here we choose to simply set the array and not trigger the counter
  28. counter([10,20,40,60,80]);
  29. counter();
  30. counter()
  31. trace("reset the counter:");
  32. // reset and the counter is called 3 times
  33. counter("reset")()()();
  34.  
  35. /*outputs :
  36. count through the array:
  37. a
  38. b
  39. c
  40. change the array:
  41. 10
  42. 20
  43. reset the counter:
  44. 10
  45. 20
  46. 40
  47. */

Today I felt like messing around with functions and this is the result. This snippet shows a strange and interesting technique to create a function that iterates through a given array in a few different ways.

I believe the technical term for this kind of thing is a continuation...

There are a bunch of other posts like this on actionsnippet. Some are purely experimental, others are actually quite useful... these can all be found in the functions category.

Posted in dynamic, functions | Tagged , , | Leave a comment