点击图像打开实例文件：

PBK文件源码：

<languageVersion : 1.0;>

# define PI 3.141592
# define DOUPLEPI 6.28318531

kernel RadialCaleidoscope
<   namespace : "RadialCaleidoscope";
    vendor : "ChenTong";
    version : 1;
    description : "Caleidoscope -effect for radial reflection";
>
{
    parameter float angle
        // 类似于 2*PI/n, 整数 n >3
        <
        minValue:float(0.0001);
        maxValue:float(PI);
        defaultValue:float(0.628318531); 
        >;
    parameter float direction
        <
        minValue:float(0.0);
        maxValue:float(DOUPLEPI);
        defaultValue:float(0.0001);
        >;     
    parameter float2 basepoint 
        // 或 中心点
        <
        minValue:float2(0.01);
        maxValue:float2(496.01,496.01);
        defaultValue:float2(150.01,150.01);
        >;

    input image4 src;
    output pixel4 dst;
    
    void
    evaluatePixel()
    {
        //  相对于中心点(基点)的位置
        float2 po = outCoord() - basepoint;
        //  极坐标的角度和半径
        //  加 4*PI 保持角度为正角度
        float theta = atan(po.y,po.x)-direction +2.0*DOUPLEPI;
        float radius = sqrt(po.x*po.x+po.y*po.y);
        
        //  求余操作
        float newAngle = mod(theta,angle);
        float section = floor(theta/angle);
        
        //  镜像奇数位置
        if (mod(section,2.0)>0.5) newAngle = angle-newAngle;
        
        //  将极坐标转换为平面直角坐标
        dst = sampleLinear(src,basepoint+float2(radius *cos(newAngle += direction), radius *sin(newAngle)));
    }
}

AS类文件：

package{
	import flash.display.Bitmap;
	import flash.display.GradientType;
	import flash.display.Shader;
	import flash.display.Shape;
	import flash.display.Sprite;
	import flash.display.StageAlign;
	import flash.display.StageScaleMode;
	import flash.events.Event;
	import flash.filters.ShaderFilter;
	import flash.geom.Matrix;
		
	[SWF(width="800",height="600",frameRate="10",backgroundColor="0x000000")]
	public class RadialKaleidoscope extends Sprite{
		[Embed(source="pbj/RadialCaleidoscope.pbj",mimeType="application/octet-stream")]
		private var ShaderClass:Class;
		
		[Embed(source="assets/Flower6.jpg")]
		private var Flower:Class;
		
		private var container:Sprite;
		private var shader:Shader;
		private var filter:ShaderFilter;
		
		private var image:Bitmap;
		private var maskShape:Shape;
		private var gradientShape:Shape;
		private var radius:Number = 250;
		
		private var angle:Number = 0;
		private var value:Number = 0;
		
		public function RadialKaleidoscope(){
			stage.align = StageAlign.TOP_LEFT;
			stage.scaleMode = StageScaleMode.NO_SCALE;
			
			container = new Sprite();
			addChild(container);
			
			shader = new Shader(new ShaderClass());
			shader.data.basepoint.value = [256.0,192.0];
			shader.data.angle.value = [0.2168];
			filter = new ShaderFilter(shader);
			image = new Flower();
			container.x = (800-image.width)/2;
			container.y = (600-image.height)/2;
			container.addChild(image);			
			image.filters = [filter];
			
			maskShape = new Shape();
			maskShape.graphics.beginFill(0xffffff,1);
			maskShape.graphics.drawCircle(0,0,radius);
			maskShape.graphics.endFill();
			addChild(maskShape);
			maskShape.x = 400;
			maskShape.y = 300;
			container.mask = maskShape;
			
			gradientShape = new Shape();
			var matrix:Matrix = new Matrix();
			var colors:Array = [0x000000,0x000000];
			var alphas:Array = [0,1];
			var ratios:Array = [150,255];
			matrix.createGradientBox(radius*2,radius*2,0,-radius,-radius);
			gradientShape.graphics.lineStyle();
			gradientShape.graphics.beginGradientFill(GradientType.RADIAL,colors,alphas,ratios,matrix);
			gradientShape.graphics.drawCircle(0,0,radius);
			gradientShape.graphics.endFill();
			addChild(gradientShape);
			gradientShape.x = 400;
			gradientShape.y = 300;
			
			addEventListener(Event.ENTER_FRAME,onEnterframe);
		}
		
		private function onEnterframe(e:Event):void{
			value = Math.cos(angle+=0.02)*Math.PI+Math.PI*2;
			shader.data.direction.value = [value];
			image.filters = [filter];
		}
	}
}

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