Glitch Auto-asteroids

By Zevan | January 25, 2009
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width=600, height=400, backgroundColor=0x000000, frameRate=30)]
  2. // make some ships
  3. for (var i:int = 0; i<10; i++) makeShip();
  4. //
  5. function makeShip():void {
  6.     // setup vars
  7.     var char:Object ={posX:Math.random()*stage.stageWidth, posY:Math.random()*stage.stageHeight, velX:0, velY:0, rad:4, theta:Math.random()*6.28, thetaDest:Math.random()*6.28, mc: MovieClip(addChild(new MovieClip()))}
  8.     // draw and position the char
  9.     with(char.mc) graphics.lineStyle(0,0xFFFFFF), graphics.moveTo(-15, -5), graphics.lineTo(0, 0), graphics.lineTo(-15, 5), x=char.posX, y=char.posY;
  10.     // loop
  11.     addEventListener(Event.ENTER_FRAME, function(){
  12.         // change position based on velocity, .9 friction
  13.         with (char) posX += velX *= .9, posY += velY *= .9;
  14.         // randomize radius and theta
  15.         if (int(Math.random()*10) == 1) char.thetaDest += Math.random()*2-1;
  16.         if (int(Math.random()*90) == 1) char.rad = Math.random()*4 + 4
  17.         // apply changes to velocity
  18.         char.theta += (char.thetaDest - char.theta) / 12;
  19.         char.velX = char.rad * Math.cos(char.theta);
  20.         char.velY = char.rad * Math.sin(char.theta);
  21.         // screen bounds
  22.         if (char.posX> 620) char.posX = -20;
  23.         if (char.posX <-20) char.posX = 620;
  24.         if (char.posY> 420) char.posY = -20;
  25.         if (char.posY <-20) char.posY = 420;
  26.         // rotation
  27.         char.mc.rotation = (Math.abs(char.mc.y - char.posY)>.7 || Math.abs(char.mc.x - char.posX)> .7) ?  Math.atan2(char.posY - char.mc.y,char.posX -  char.mc.x) / Math.PI * 180 : char.mc.rotation;
  28.         // shoot
  29.         if(int(Math.random()*100) <20) shootBullet(char, 5 * Math.cos(char.mc.rotation * Math.PI / 180)+ char.velX, 5 * Math.sin(char.mc.rotation * Math.PI / 180) + char.velY);
  30.         // apply position
  31.         with(char) mc.x = posX, mc.y = posY;
  32.         });
  33. }
  34. //
  35. function shootBullet(char:Object, vx:Number, vy:Number):void{
  36.     var b:MovieClip = MovieClip(addChild(new MovieClip()));
  37.     b.life = 0;
  38.     with(b) graphics.beginFill(0xFFFFFF), graphics.drawCircle(0,0,2), x = char.mc.x, y = char.mc.y;
  39.     b.addEventListener(Event.ENTER_FRAME, function(){
  40.             with (b) x += vx, y += vy, life++;
  41.             if (b.life> 30) b.removeEventListener(Event.ENTER_FRAME, arguments.callee), removeChild(b);
  42.     });
  43. }

An asteroids inspired code snippet. See the swf here.

Posted in misc, motion | Tagged , | Leave a comment

Zeno’s [classic easeOut]

By Zevan | January 24, 2009
CLICK HERE TO COPY
Actionscript:
  1. stage.frameRate = 30;
  2. var circle:Shape = Shape(addChild(new Shape()));
  3. with(circle.graphics) beginFill(0x000000), drawCircle(0,0,10);
  4. circle.y = 50;
  5.  
  6. addEventListener(Event.ENTER_FRAME, onLoop);
  7. function onLoop(evt:Event):void {
  8.     circle.x += (mouseX - circle.x) / 12;
  9. }

Posted in motion, one-liners | Tagged , | Leave a comment

Point.polar() Stars

By Zevan | January 23, 2009
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width=700, height=400, backgroundColor=0x000000, frameRate=30)]
  2.  
  3. var points:Array = new Array();
  4. var index:int = -1;
  5. function polar(thetaInc:Number, radius:Number):Point{
  6.     index++;
  7.     if (!points[index]) points[index] = 0;
  8.     return Point.polar(radius, points[index] += thetaInc)
  9. }
  10. ///////////////////////////////////////////////////
  11. // test it out:
  12.  
  13. var canvas:BitmapData = new BitmapData(700, 400, false, 0xFFFFFF);
  14.  
  15. addChild(new Bitmap(canvas, "auto", true));
  16.  
  17. var p0:Point = new Point(200, 200);
  18. var p1:Point = new Point(500, 200);
  19.  
  20. addEventListener(Event.ENTER_FRAME, onLoop);
  21. function onLoop(evt:Event):void {
  22.    
  23.     var rad:Point = polar(.05, 4);
  24.      
  25.     for (var i:int= 0; i<100; i++){
  26.        
  27.         // reset index;
  28.         index = -1;
  29.        
  30.         p0 = p0.add(polar(.025, 2).add(polar(-.05,rad.x)));
  31.         canvas.setPixel(p0.x, p0.y, 0x000000);
  32.        
  33.         p1 = p1.add(polar(.025, 2).add(polar(-.05,rad.x).add(polar(.1, rad.y))));
  34.         canvas.setPixel(p1.x, p1.y, 0x000000);
  35.     }
  36. }

This is pretty much the same as yesterdays... I just changed the way I use the polar() function to draw two more shapes:

Posted in BitmapData, motion, setPixel | Tagged , | Leave a comment

Playing with Curves Point.polar()

By Zevan | January 22, 2009
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width=600, height=500, backgroundColor=0x000000, frameRate=30)]
  2. var points:Array = new Array();
  3. var index:int = -1;
  4. function polar(thetaInc:Number, radius:Number):Point{
  5.     index++;
  6.     if (!points[index]) points[index] = 0;
  7.     return Point.polar(radius, points[index] += thetaInc);
  8. }
  9. ///////////////////////////////////////////////////
  10. // test it out:
  11.  
  12. var canvas:BitmapData = new BitmapData(600, 500, false, 0xFFFFFF);
  13.  
  14. addChild(new Bitmap(canvas, "auto", true));
  15.  
  16. var p0:Point = new Point(80, 100);
  17. var p1:Point = new Point(270, 100);
  18. var p2:Point = new Point(480, 40);
  19. var p3:Point = new Point(170, 180);
  20. var p4:Point = new Point(430, 300);
  21.  
  22. addEventListener(Event.ENTER_FRAME, onLoop);
  23. function onLoop(evt:Event):void {
  24.     for (var i:int= 0; i<100; i++){
  25.        
  26.         // reset index;
  27.         index = -1;
  28.        
  29.         p0 = p0.add(polar(.2, 4).add(polar(-.4,2).add(polar(.05, 1))));
  30.         canvas.setPixel(p0.x, p0.y, 0x000000);
  31.    
  32.         p1 = p1.add(polar(.1, 2).add(polar(-.2, 2).add(polar(.03, 1).add(polar(-.01,.5)))));
  33.         canvas.setPixel(p1.x, p1.y, 0x000000);
  34.      
  35.         p2 = p2.add(polar(.08, 3 ).add(polar(-.2, -12).add(polar(2, 10))));
  36.         canvas.setPixel(p2.x, p2.y, 0x000000);
  37.      
  38.         p3 = p3.add(polar(.08, 7).add(polar(-.2, -12).add(polar(2, 11))));
  39.         canvas.setPixel(p3.x, p3.y, 0x000000);
  40.        
  41.         p4 = p4.add(polar(.025, 2).add(polar(-.05,1)));
  42.         canvas.setPixel(p4.x, p4.y, 0x000000);
  43.     }
  44. }

The polar() function is the real trick here... the rest of the code just uses it to draw this:

The Point.polar() function is just a conversion from polar to cartesian coords:

CLICK HERE TO COPY
Actionscript:
  1. x = radius * Math.cos(theta);
  2. y = radius * Math.sin(theta);

Posted in motion, setPixel | Tagged , | Leave a comment