Actionscript:
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[SWF(width=600,height=500,frameRate=30)]
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var canvas:BitmapData=new BitmapData(400,400,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 pix:Vector.<uint> = new Vector.<uint>(size);
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addEventListener(Event.ENTER_FRAME, onLoop);
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function onLoop(evt:Event):void {
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canvas.lock();
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var i:int = size;
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var x1:Number=mouseX;
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var y1:Number=mouseY;
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var x2:Number=250;
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var y2:Number=250;
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var dx:Number=x2-x1;
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var dy:Number=y2-y1;
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var denom:Number = 1/(dx * dx + dy * dy);
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if (dx==0&&dy==0) {
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x2+=1;
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y2+=1;
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dx=dy=1;
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}
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while( --i> -1 ){
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var xp:int= i % w;
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var yp:int = i / w;
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var u:Number = ((xp - x1) * dx + (yp - y1) * dy) * denom;
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var closestX:Number;
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var closestY:Number;
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if (u<0) {
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closestX=x1;
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closestY=y1;
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} else if (u> 1) {
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closestX=x2;
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closestY=y2;
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} else {
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closestX=x1+u*dx;
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closestY=y1+u*dy;
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}
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var dfx:Number=closestX-xp;
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var dfy:Number=closestY-yp;
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var d:Number=255-Math.sqrt(dfx*dfx+dfy*dfy);
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if (d<0) d=0;
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pix[i]=uint(d);
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}
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canvas.setVector(canvas.rect, pix);
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canvas.unlock();
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}
This didn't come out as interesting as I thought it would for some reason - just used the technique from the last two posts to draw a gradient. Event though it's visually boring, it does show how I went about inlining the function from yesterday... so I figured I'd post it.
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:
Recently saw some great links making use of Global Illumination/Ambient Occlusion... these ones are from wonderfl posted by keim at Si :
This first example is based on something called AO bench.
one
two
three
and there is something called MiniLight which has been ported to Flex.
Actionscript:
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var size:Number = 800;
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var canvas:BitmapData = new BitmapData(size,size,false, 0x000000);
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addChild(new Bitmap(canvas, "auto", true));
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scaleX = scaleY = .5;
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var pix:Number = size * size;
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var scale:Number = 1/(size/3);
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-
for (var i:Number = 0; i<pix; i++){
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var xp:Number = (i % size);
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var yp:Number = int(i / size);
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var xt:Number = xp * scale;
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var yt:Number = yp * scale;
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var ca:Number = (Math.abs(Math.tan(yt) * Math.pow(Math.sin(xt),3)) * 100 ) % 155;
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var cb:Number = (Math.abs(Math.tan(xt) * Math.pow(Math.sin(yt),3)) * 100) % 155;
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ca|= cb;
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canvas.setPixel(xp, yp, ca <<16 | ca <<8 | ca);
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}
Another messy code snippet that I e-mailed to myself at some point...
Try replacing line 16 with some of these variations:
ca &= cb;
ca += cb;
ca -= cb;
ca ^= cb;
ca %= cb