flash – 使用PixelBender将位图的大小加倍

我有一个关于像素弯曲的性能问题.我想放大许多BitmapData(将它们的大小加倍到新的BitmapData).我是用as3做的,但是想用像素弯曲器来获得更好的性能.在我的机器上,我从像素弯曲机 demonstrations然后as3获得更好的性能.

令我惊讶的是(或编码/理解不好),我在像素弯曲器中的表现要差得多 – 2秒vs 1/2秒！我期望得到至少与as3相同的性能.我究竟做错了什么？

我得到了直接的像素弯曲代码here(它包含在下面以便于参考).

package
{

import flash.display.BitmapData;
import flash.display.Shader;
import flash.display.ShaderJob;
import flash.display.Sprite;
import flash.display.StageAlign;
import flash.display.StageScaleMode;
import flash.events.Event;
import flash.geom.Matrix;

public class flashFlash extends Sprite
{


[Embed ( source="pixelbender/bilinearresample.pbj",mimeType="application/octet-stream" ) ]
private static var BilinearScaling:Class;

public function flashFlash( ):void
{
    stage.align = StageAlign.TOP_LEFT;
    stage.scaleMode = StageScaleMode.NO_SCALE;

    addEventListener( Event.ENTER_FRAME,efCb,false,true );
}

private function efCb( evt:Event ):void
{
    removeEventListener( Event.ENTER_FRAME,false );

    traceTime( "init" );

    var srcBmd:BitmapData = new BitmapData( 80,120,0 );
    var destBmd:BitmapData = new BitmapData( 160,240,0 );

    var mx:Matrix = new Matrix( );
    mx.scale( 2,2 );
    for (var i:uint = 0; i < 3000; i++)
    {   destBmd.draw( srcBmd,mx );
    }

    traceTime( "scaled with as3" );

    // create and configure a Shader object
    var shader:Shader = new Shader( );
    shader.byteCode = new BilinearScaling( );
    shader.data.scale.value = [.5];
    shader.data.src.input = srcBmd;

    for (var j:uint = 0; j < 3000; j++)
    {
        var shaderJob:ShaderJob = new ShaderJob( );
        shaderJob.shader = shader;
        shaderJob.target = destBmd;
        shaderJob.start( true );
    }

    traceTime( "scaled with pixel bender bilinearresample.pbj" );
}

private static var _lastTraceTime:Number = new Date().getTime();
public static function traceTime( note:String ):Number
{   var nowTime:Number = new Date().getTime();
    var diff:Number = (nowTime-_lastTraceTime);
    trace( "[t" + diff + "] " + note );
    _lastTraceTime = nowTime;
    return diff;
}

}
}

和像素弯曲代码：

<languageVersion : 1.0;>

kernel BilinearResample
<   namespace : "com.brooksandrus.pixelbender";
    vendor : "Brooks Andrus";
    version : 1;
    description : "Resizes an image using bilinear resampling. Constrains aspect ratio - divide Math.max( input.width / output.width,input.height / output.height ) and pass in to the scale parameter";
>
{
    parameter float scale
    <
        minValue: 0.0;
        maxValue: 1000.0;
        defaultValue: 1.0;
    >;

    input image4 src;
    output pixel4 dst;

    void
    evaluatePixel()
    {
        // scale should be Math.max( src.width / output.width,src.height / output.height )
        dst = sampleLinear( src,outCoord() * scale ); // bilinear scaling
    }
}