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reference: tech-ni

by cosaic 14 Jul 2009

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/**
 * Copyright cosaic ( http://wonderfl.net/user/cosaic )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/7uWB
 */

/**
 * reference: tech-ni
 */
package {
	import flash.display.Sprite;
	import flash.display.*;
	import flash.filters.*;
	import flash.geom.*;
	
	public class FlashTest extends Sprite
	{
		private const WIDTH:int = 200;
		private const HEIGHT:int = 150;
		
		public function FlashTest()
		{
			scaleX = scaleY = 2;
			
			// Create circle
			var circle:Sprite = new Sprite();
			circle.graphics.beginFill(0x808080);
			circle.graphics.drawCircle(0, 0, 10);
			circle.graphics.endFill();
			
			// Create buffered image
			var fire:BitmapData = new BitmapData(WIDTH, HEIGHT, false, 0);
			var pg:BitmapData = fire.clone();
			var noiseBmd:BitmapData = new BitmapData(WIDTH, 1);
			
			var bmp:Bitmap = new Bitmap(pg);
			addChild(bmp);
			
			// Generate the palette
			var r:Array = [], g:Array = [], b:Array = [];
			for(var x:int = 0; x < 256; x++)
                        {
				//Hue goes from 0 to 85: red to yellow
				//Saturation is always the maximum: 255
				//Lightness is 0..255 for x=0..128, and 255 for x=128..255
				HSVtoRGB(x / 3, 1, Math.min(x * 3 / 255.0, 1), r, g, b);
			}
			
			// Use ConvolutionFilter to calculate for every pixel
			var filter:ConvolutionFilter = new ConvolutionFilter(3, 3, [0, 0, 0, 16, 16, 16, 0, 16, 0], 65);
			
			// Prepare points and matrix
			var matrix:Matrix = new Matrix();
			var pt0:Point = new Point(0, HEIGHT - 1);
			var pt1:Point = new Point(0, -1);
			var pt2:Point = new Point(0, 1);
			
			// Do loop
			addEventListener("enterFrame", function(event:*):void
			{
				// Randomize the bottom row of the fire buffer
				noiseBmd.noise(Math.random() * 0xffffffff, 0, 190, 7, true);
				fire.copyPixels(noiseBmd, noiseBmd.rect, pt0);
				
				// Display circle
				matrix.tx = mouseX;
				matrix.ty = mouseY;
				fire.draw(circle, matrix);
				
				// Add pixel values around current pixel
				fire.applyFilter(fire, fire.rect, pt1, filter);
				
				// Output everything to screen using our palette colors
				pg.paletteMap(fire, fire.rect, pt2, r, g, b);
			});
		}
		
		// AS3 does not natively support HSV...  :-(
		private function HSVtoRGB(h:int, s:Number, v:Number, r:Array, g:Array, b:Array):void
		{
			if (h < 60)
			{
				r.push((v * 255) << 16);
				g.push((v * (1 - (1 - h / 60.0) * s) * 255) << 8)
				b.push(v * (1 - s) * 255);
			}
			else if (h < 120)
			{
				r.push((v * (1 - (-h / 60.0 - 1) * s) * 255) << 16);
				g.push((v * 255) << 8);
				b.push(v * (1 - s) * 255);
			}
			else
			{
				throw Error('not implemented');
			}
		}
	}
}