Monthly Archives: March 2010

Bracket Syntax Reminder

If you haven't looked at every post on this site it's possible you've missed one of my favorite actionscript features.... Bracket Syntax:

  1. var s:Sprite = Sprite(addChild(new Sprite()));
  2. s["x"] = 100;
  3. s["y"] = 100;
  5. s["graphics"]["beginFill"](0xFF0000);
  6. s["graphics"]["drawCircle"](0,0,10);
  8. this["addChild"](s);

If you don't realize how powerful this is then there is something wrong with you (joking). If you don't see how powerful this is, take some time and think about it. You can use it to avoid lots of annoying repetitive code in state machines for instance. It's always important to keep things readable if you decide to go this route on a real project.

[EDIT ....and as Quasimondo mentioned there is a notable performance hit when using this syntax. So don't forget to keep that in mind.]

Here is a very old post showing some of the power of this trick.

Posted in dynamic, functions | Tagged , , | 4 Comments

URLVariables Replacement

  1. function decode(str:String):Object {
  2.     var vars:Object={};
  3.     var parse:Array =str.split("&");
  4.     var i:int=0;
  5.     for (i = 0; i<parse.length; i++) {
  6.         var pair:Array=parse[i].split("=");
  7.         if (pair.length==2) {
  8.             vars[pair[0]]=pair[1];
  9.         }
  10.     }
  11.     return vars;
  12. }
  14. var nameValuePairs="one=1&&two=éllo&three=1000&four=0xFF0000";
  15. var parsed:Object=decode(nameValuePairs);
  17. trace(;
  18. trace(parsed.two);
  19. trace(parsed.three);
  20. trace(parsed.four);
  22. /*outputs:
  23. 1
  24. éllo
  25. 1000
  26. 0xFF0000
  27. */

Well not exactly a URLVariables replacement, but I often use the URLVariables.decode() function and find that its very picky... like if there is an extra & or something it freaks out and breaks, or if there are line returns. As a quick and simple solution the other day I wrote this function into part of a class (Model class) that I was working on. Fixed the problem and even handles Spanish characters nicely.

There is plenty of room for improvement with this simple function... feel free to post improvements in the comments.

Posted in external data, string manipulation, strings | Tagged , , | 3 Comments

Colors For Questions

I get lots of questions about actionscript and QuickBox2D. Too many questions to answer really. But if you enter 30 colors into this project I'm working on I'll help you by answering any question (within reason of course) and possibly giving you a code snippet related to your question.

To enter colors use you'll be using a simple color picker app. Select a color, give it a name "dark red, maroon" etc.. and Then post in the comments that you did so... You'll need to enter a contributer name as well... you can use a handle or your real name... doesn't matter. So go back to this post and watch how to go about adding colors. If you have a question about how to enter stuff, here is the place to ask it....

Posted in Uncategorized | 11 Comments

Polygon Problems

Lots of people have mentioned that they have problems with QuickBox2D Polygons. The simple solution is not to use the verts 2d array (which is more like how Box2D does polys). So when in doubt about polygons, simply use the points array which will nearly always work as long as the contour you define does not cross over itself. Here is a simple example on wonderfl:

Also... polygons are covered extensively in part two of the tutorial over at active tuts... more on that later.

Here is the timeline code:

  1. import com.actionsnippet.qbox.*;
  2.             /*
  3.                0
  4.               / \
  5.              0_0 0
  6.                | |
  7.                0-0
  8.             */
  9.             var sim:QuickBox2D = new QuickBox2D(this);
  10.             sim.createStageWalls();
  11.             // define the contour of your poly
  12.             // no limits as long as it doesn't cross over
  13.             // itself
  14.             sim.addPoly({x:10, y:5, points:[0.5,0,
  15.                                             1, 1,
  16.                                             1, 2,
  17.                                             0.5, 2,
  18.                                             0.5, 1,
  19.                                             0,1,
  20.                                             0.5,0],
  21.                                             wireframe:false});
  22.             sim.addCircle({x:11, y:10});
  23.             sim.start();
  24.             sim.mouseDrag();

Posted in Uncategorized | Tagged , , , | Leave a comment