Category Archives: dynamic

Dynamic Graphics and Function.apply()

By Zevan | February 5, 2009
CLICK HERE TO COPY
Actionscript:
  1. var cmds:Array = [["lineStyle", 0, 0xFF0000], ["drawCircle",100, 100, 50], ["drawRect", 50, 50, 100, 100]];
  2. cmds.push(["drawCircle", 100, 100, 70]);
  3. cmds.push(["beginFill",  0x555555]);
  4. cmds.push(["drawRoundRect", 80, 80, 40, 40, 10, 10]);
  5. cmds.push(["endFill"]);
  6.  
  7. render(cmds);
  8.  
  9. function render(p:Array):void {
  10.     for (var i:int = 0; i<p.length; i++) {
  11.         graphics[p[i][0]].apply(graphics,p[i].splice(1));
  12.     }
  13. }

The above creates a function called render() that takes a 2D array of Graphics class methods and then runs them. This is a very interesting technique, specifically if you'd like to write Graphics class method calls in an XML or txt file and then have them run on a given DisplayObject in flash.

I've been thinking about the best way to do this for awhile... I started off doing something very convoluted and then realized that I could use Function.apply()....

Tomorrow I'll post a snippet showing how to use this function in conjunction with XML.

Also posted in Graphics, functions | Tagged , | 2 Comments

Snippet Template (imports)

By Zevan | February 2, 2009
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Actionscript:
  1. package {
  2.     import adobe.utils.*;
  3.     import flash.accessibility.*;
  4.     import flash.display.*;
  5.     import flash.errors.*;
  6.     import flash.events.*;
  7.     import flash.external.*;
  8.     import flash.filters.*;
  9.     import flash.geom.*;
  10.     import flash.media.*;
  11.     import flash.net.*;
  12.     import flash.printing.*;
  13.     import flash.profiler.*;
  14.     import flash.sampler.*;
  15.     import flash.system.*;
  16.     import flash.text.*;
  17.     import flash.ui.*;
  18.     import flash.utils.*;
  19.     import flash.xml.*;
  20.    
  21.     dynamic public class Snippet extends MovieClip {
  22.         public function Snippet() {
  23.              // paste your snippet here (functions and all)
  24.         }
  25.     }
  26. }

This snippet imports all flash packages and is dynamic... you can copy actionsnippet code into the constructor of this file if you use Flex, FlashDevelop, TextMate etc... I tested it with a bunch of snippets and it seems to work nicely.

When I first teach classes in AS3 this is the template I use:

CLICK HERE TO COPY
Actionscript:
  1. package{
  2.     import flash.display.*;
  3.     import flash.events.*;
  4.      
  5.     public class Main extends Sprite{
  6.         // etc...
  7.     }
  8. }

Display and events cover a lot of ground..... next one I find myself adding is flash.geom, followed by flash.net... I'd say those are my top 4 most frequently used packages.... I do lots of text layout in the Flash IDE, otherwise flash.text would be in there....

Also posted in OOP, misc, timeline | Tagged , | 4 Comments

nesting(function(calls()))

By Zevan | January 17, 2009
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Actionscript:
  1. [SWF(width=500, height=500, backgroundColor=0x000000, frameRate=30)]
  2.  
  3. for (var i:int = 0; i<10; i++){
  4.        // draggable ellipse
  5.     var dot:Sprite = drag(createSprite("Ellipse",  -10, -10, 20, 20));
  6.     dot.x = Math.random() * stage.stageWidth ;
  7.     dot.y = Math.random() * stage.stageHeight ;
  8. }
  9.  
  10. for (i = 0; i<10; i++){
  11.  
  12.       var box:Sprite = drag(spin(createSprite("Rect", -20, -20, 40, 40, 0xFF0000), Math.random()*5 + 1));
  13.     box.x = Math.random() * stage.stageWidth ;
  14.     box.y = Math.random() * stage.stageHeight ;
  15. }
  16.  
  17.  
  18.  // createSprite can create ellipses or rectangles
  19. function createSprite(shape:String, xp:Number, yp:Number, w:Number, h:Number, col:uint=0x444444):Sprite {
  20.     var s:Sprite = new Sprite();
  21.     s.graphics.beginFill(col);
  22.     // trick from a previous post
  23.     s.graphics["draw" + shape](xp, yp, w, h);
  24.     addChild(s);
  25.     return s;
  26. }
  27.  
  28. // drag and spin add listeners to an untyped target and return that target for easy function nesting
  29. function drag(target:*):*{
  30.     target.addEventListener(MouseEvent.MOUSE_DOWN, function(evt:MouseEvent){ evt.currentTarget.startDrag(); });
  31.     return target;
  32. }
  33.  
  34. function spin(target:*, speed:Number):*{
  35.     target.addEventListener(Event.ENTER_FRAME, function(evt:Event){ evt.currentTarget.rotation+=speed; });
  36.     return target;
  37. }
  38.  
  39. stage.addEventListener(MouseEvent.MOUSE_UP, function(){ stopDrag() });

The above will create some draggable circles and some rotating draggable rects... but that's not really the point....

When prototyping and just playing around I write functions that take an Object as an argument, alter that Object in some way and pass that some Object out as a return value.... this makes it so I can write things like this:

CLICK HERE TO COPY
Actionscript:
  1. drag(spin(createSprite("Rect", -20, -20, 40, 40, 0xFF0000), Math.random()*5 + 1));

Readability can be a problem so... consider that before using this for anything...

Also posted in functions, misc | Tagged , | Leave a comment

Dynamic Vars Dictionary

By Zevan | December 26, 2008
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Actionscript:
  1. var vars:Dictionary = new Dictionary();
  2.  
  3. var sp:Sprite = new Sprite();
  4.  
  5. // associate variables with a sprite (or any non-dynamic class)
  6. vars[sp] = {posX:100, posY:100, velX:1, velY:1};
  7.  
  8. // read
  9. trace(vars[sp].posX);

I've heard people mention that they wish the sprite class were dynamic... meaning they wish they could add methods and properties to a Sprite instance at runtime. There's no way I know of to do this, however... the dictionary class can be used to associate variables with any non-dynamic class instance... as it does in this the above example.

The dictionary class is similar to an associative array except that instead of using strings for keys, dictionaries use object instances.

Also posted in Dictionary, arrays | Tagged , | 1 Comment