Actionscript:
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// from http://codebase.dbp-site.com/code/find-difference-between-two-angles-25
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function angleDifference(angle0:Number, angle1:Number):Number{
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return Math.abs((angle0 + 180 - angle1) % 360 - 180);
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}
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trace("get the angle between:");
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trace("350 and 10 =", angleDifference(350, 10));
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trace("180 and -1 =", angleDifference(180, -1));
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trace("-10 and 5 =", angleDifference(-10, 5));
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trace("725 and -45 =", angleDifference(725, -45));
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/* outputs:
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get the angle between:
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350 and 10 = 20
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180 and -1 = 179
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-10 and 5 = 15
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725 and -45 = 50
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*/
This snippet shows an easy way to find the difference between two angles. The tricky part about doing this is finding the difference between something like 350 and 1 (which should be 11).
Over the years I have done this a few different ways - I needed it for something today and realized that my way was a tad clunky (had a little redundant logic) - So with a quick google search I found a more elegant solution.
Actionscript:
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var count:int = 0;
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var cursors:Array = [MouseCursor.ARROW, MouseCursor.BUTTON, MouseCursor.HAND, MouseCursor.IBEAM];
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setInterval(changeMouse, 100);
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function changeMouse():void{
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Mouse.cursor = cursors[count % cursors.length];
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count++;
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}
This is a small snippet that shows the cursor property of the Mouse class. This is fp10 only...
Posted in UI | Tagged actionscript, flash |
Actionscript:
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[SWF(width=600,height=500,frameRate=30)]
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var canvas:BitmapData=new BitmapData(600,500,false,0x000000);
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addChild(new Bitmap(canvas));
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var size:Number=canvas.width*canvas.height;
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var w:Number=canvas.width;
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var wd:Number=1/w;
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var pix:Vector.<uint> = new Vector.<uint>();
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var sin:Number;
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var cos:Number;
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var dx:Number=110;
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var dy:Number=52;
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addEventListener(Event.ENTER_FRAME, onLoop);
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function onLoop(evt:Event):void {
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dx+=0.001;
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canvas.lock();
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for (var i:int = 0; i<size; i++) {
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var xp:Number=i%w;
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var yp:Number=int(i*wd);
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var xx:Number=xp*0.05+dx;
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var yy:Number=yp*0.05+dy;
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var t:Number= (xx * yy) % 3.14159265;
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//compute sine
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// technique from http://lab.polygonal.de/2007/07/18/fast-and-accurate-sinecosine-approximation/
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// by Michael Baczynski
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if (t<0) {
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sin=1.27323954*t+.405284735*t*t;
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} else {
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sin=1.27323954*t-0.405284735*t*t;
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}
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//compute cosine: sin(t + PI/2) = cos(t)
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t+=1.57079632;
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if (t>3.14159265) {
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t-=6.28318531;
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}
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if (t<0) {
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cos=1.27323954*t+0.405284735*t*t;
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} else {
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cos=1.27323954*t-0.405284735*t*t;
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}
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var c:Number=sin+cos*cos*cos;
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// fast math abs
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c=c<0? -c:c;
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c=c*140;
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// math max 255
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c=c>255?255:c;
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pix[i]=c<<16|c<<8|c;
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}
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canvas.setVector(canvas.rect, pix);
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canvas.unlock();
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}
The above snippet will animate a gradient that looks like this:
Actionscript:
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import com.actionsnippet.qbox.*;
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import Box2D.Common.Math.*;
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[SWF (backgroundColor=0xaa0000, width=700, height=600)]
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const TWO_PI:Number = Math.PI * 2;
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var sim:QuickBox2D = new QuickBox2D(this,{gravityY:20, debug:false});
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var i:int = 0;
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// add some circles
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var circles:Array = [];
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var circleNum:int = 20;
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for (i = 0; i<circleNum; i++){
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circles[i] = sim.addCircle({x: 8, y:-2 - i, radius:0.1 + Math.random()*0.4, fillColor:0x000000});
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}
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// add some boxes
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var boxes:Array = [];
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var boxNum:int = 20;
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for (i= 0; i<boxNum; i++){
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var rx:Number = 4 + (i % 5) * 4;
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var ry:Number = 4 + int(i / 5) * 4;
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var ra:Number = Math.random() * TWO_PI;
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boxes[i] = sim.addBox({x:rx, y:ry, width:3, height:0.4, angle:ra, density:0,fillColor:0xFF2200});
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}
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// vector(0,0) used to reset velocity
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var resetVec:b2Vec2 = new b2Vec2();
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sim.start();
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sim.mouseDrag();
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addEventListener(Event.ENTER_FRAME, onLoop);
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function onLoop(evt:Event):void {
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// rotate all boxes
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for (i= 0; i<boxNum; i++){
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boxes[i].angle += .05;
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}
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// move circles to top of sceen after they fall off bottom
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for (i= 0; i<circleNum; i++){
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if (circles[i].y> 20){
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circles[i].y = -1;
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circles[i].x = Math.random()*(stage.stageWidth / 30 - 9) + 4;
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// access to Box2D b2Body methods
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circles[i].body.SetLinearVelocity(resetVec);
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}
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}
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}
This is another QuickBox2D experiment. If you don't know what QuickBox2D is ... read about it here.
Take a look at the swf here
