darqwan’s cookie jar..

The jumpy MovieClip.. is caused by Flash moving the content of the movieclip pixel by pixel. This, although Flash is capable of subpixel operations via it’s AntiAliasing engine, in some circumstances it will discard them. Most of this circumstances are related to speed optimizations and/or bugs on the Flash player. The first thing you need to do if you find that the animation of the movieclip is not smooth, is to disable cacheAsBitmap. cacheAsBitmap inherently disables sub pixel operations thus, if set to true, the movieclips (or any other displayobject for that matter) will have a sloppy animation.

PixelSnapping.. If you create/load the content of the display object at runtime, ie load a bitmap or create one via a bitmapdata.draw AND want smooth animation you will have to specify pixelsnapping. PixelSnapping is a property of the Bitmap class, that can have 3 values, NEVER,ALWAYS,AUTO. By default it’s set to AUTO which causes some snapping to occur in some circumstances. Set this to NEVER.

The filters.. As I stated earlier, some cases in which pixelsnapping always enabled are due to some optimizations required. The use of filters is one of these cases. Basically whenever you add a filter to a displayobject the cacheAsBitmap property will always be overriden to true. There’s no way that I know of to over-override this and probably even if there would be, I suspect the end results would be less than acceptable.

the hack.. If you still decide that you want to use filters and also must have smooth animation, there’s at least a way to deal with it. This consists of drawing the movieclip with the filters on into a bitmapdata, creating a bitmap with pixelsnapping set to never with this bitmapdata and using it instead of the original movieclip. This works quite well with movieclips that are static (sprites) since because of rendering the filter also, the renderer has one less thing to do (even if this is cached at runtime).

of course, if someone wants a snippet of the code, just let me know,

dw.

Tags: actionscript, Things you probably didnt knew about Flash

This entry was posted on Thursday, July 23rd, 2009 at 11:22 am and is filed under Action Script, Flash. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.