Displacement filter cpu usage problem

[phil7]

Hi, i'm using the displacement filter to create a magnify glass effect on my image.

Using similar code to the example from adobe found at:

http://livedocs.adobe.com/flex/3/htm...bjects_18.html

Using adobes example uses about 22% of my cpu. (Pentium 4 3.4 ghz)

The image im using the effect on is quite large at over 1000 px * 1000 px and layer masking is involved so this pushes cpu usage up to 85%.

However, i have code which moves the magnified image and the magnifier at the same time and this way cpu usage is simply too high and it stutters.

Does anyone know how I can reduce the cpu usage used by the displacement filter?

This is a snippet of my code:

	

var filterX:Number = houseBig.mouseX;     //(houseBig.mouseY) - (map.width / 2);
var filterY:Number = houseBig.mouseY;       //(houseBig.mouseY) - (map.height / 2); 
var xyFilter:DisplacementMapFilter = new DisplacementMapFilter(); 


the code below inside a function which has to be repeated


filterX = (magnify.x) - (houseBig.x) ;
	filterY = (magnify.y) - (houseBig.y) ;        
	

	var pt = new Point(filterX, filterY); 
	mapBitmap.x = mouseX;
	mapBitmap.y = mouseY;
    xyFilter.mapBitmap = map; 
    xyFilter.mapPoint = pt; 
    // The red in the map image will control x displacement. 
    xyFilter.componentX = BitmapDataChannel.RED; 
    // The blue in the map image will control y displacement. 
    xyFilter.componentY = BitmapDataChannel.BLUE; 
    xyFilter.scaleX = 25; //MANIFY STRENGTH
    xyFilter.scaleY = 25; //MANIFY STRENGTH
	xyFilter.mode = DisplacementMapFilterMode.IGNORE;
	houseBig.filters = [xyFilter];

I just want to reposition the filter more efficiently when this code repeats and the houseBig variables have changed.

Thanks, Phil

[shamimsaad03]

is the full 1000x1000px viewable? if not try using a mask to render only the viewable area

[Phix]

Yea dude, displacement in any form of computer graphics is CPU intensive. I would go with the mask technique. Much easier on the 'puter.

[phil7]

Thanks for help. Thing is, as im using this for a magnifying glass effect, only a small area of the image is visible anyway. Ive tried adding another mask of the whole stage using:

houseBig.mask = stageMask;

However this removes my displacement filter effect.

[Phix]

Keep in mind also that, unless you're creating this for educational purposes, if you distribute, people are going to be on everything from netbooks to workstations. If a 3.4 is being pushed to 85%, no way a dinky netbook/laptop will be able to use it gracefully.

My advice is to scrap the displacement idea. It's just too expensive, especially with interactivity.