yea... this is true unfortunately :( On Jul 11, 2007, at 2:40 PM, Austin Haas wrote:
> Maybe I should have said you "can" see tearing instead of you > "will" see tearing. The point is that tearing is absolutely > possible in Flash, and it occurs b/c there is no way to sync with > the vertical refresh. All of the techniques proposed, and the > performance of the client's machine, can only mitigate the problem, > not solve it completely. > > -austin > > -- > Austin Haas > Pet Tomato, Inc. > http://pettomato.com > > On Wed Jul 11 14:24 , Samuel Agesilas wrote: >> Whoa! That's a little bit of a generalization that I'm not 100% in an >> agreement with. Tearing does NOT always happen. The AVM2 display >> engine is fast enough to update the screen in most cases so tearing >> does not occur. However this is entirely up to the performance >> capabilities of the host machine. In other words the faster the >> machine the less of a chance you have an experience tearing. If you >> run flash on a Pentium 2 then you will some artifacts. As proof you >> can download a 1024x768 image and use actionscript to move it across >> the screen and you will not notice any tearing ( of course it would >> be wise to set the image to use runtime bitmap caching ). The reason >> for this is that starting in Flash 8 Adobe is using OpenGL on the Mac >> to do the final blitting to the screen. Using OpenGL for this greatly >> improves performance on the Mac platform where artifact could be seen >> the most as compared to the windows version of the plugin which if >> memory serves me correctly uses Direct X(not sure about this though). >> >> -sam >> >> On Jul 11, 2007, at 2:05 PM, Austin Haas wrote: >> >>> >>> No, we do have those problems in Flash. If you move a large image >>> horizontally across the screen, you will see tearing and there is >>> no way to fix it. The frame rate in Flash is not sync'd to the >>> refresh rate of the screen. >>> >>> Blitting just means combining pixels from one bitmap into another. >>> I suppose you could say that calling copyPixels() or draw() is >>> blitting. >>> >>> -austin >>> >>> -- >>> Austin Haas >>> Pet Tomato, Inc. >>> http://pettomato.com >>> >>> On Wed Jul 11 14:54 , Keith Peters wrote: >>>> Well it seems like true double buffering would be solving a >>>> problem we >>>> don't really have in Flash. I've also heard the term "blitting" be >>>> applied to this technique in Flash. There are a couple videos up >>>> on the >>>> fitc.ca site from the toronto 07 conference that discuss this. >>>> >>>> Austin Haas wrote: >>>>> Double buffering isn't about performance. It's about drawing the >>>>> next screen before the monitor does a vertical sync. The purpose >>>>> of double buffering is to avoid graphic issues like tearing and >>>>> shearing that occur when the screen is being updated at the same >>>>> time as it's being drawn. >>>>> >>>>> You can use two buffers to simulate the double buffer technique, >>>>> and there might be some performance gains there, and you might >>>>> reduce the chances of tearing/shearing, but calling that double >>>>> buffering would be an abuse of terminology, as that term already >>>>> has an accepted meaning. You would be misleading anyone who was >>>>> looking for a solution to the real problems that double buffering >>>>> is intended to solve. >>>>> >>>>> I'd really like to know if there are performance gains with this >>>>> technique in Flash. I thought that I tried it a while back, but >>>>> abandoned the idea after seeing no real gains. Does anyone have >>>>> any data or a live comparison? >>>>> >>>>> -austin >>>>> >>>>> >>>> >>>> >>>> _______________________________________________ >>>> osflash mailing list >>>> [email protected] >>>> http://osflash.org/mailman/listinfo/osflash_osflash.org >>>> >>> >>> _______________________________________________ >>> osflash mailing list >>> [email protected] >>> http://osflash.org/mailman/listinfo/osflash_osflash.org >> >> >> _______________________________________________ >> osflash mailing list >> [email protected] >> http://osflash.org/mailman/listinfo/osflash_osflash.org >> > > _______________________________________________ > osflash mailing list > [email protected] > http://osflash.org/mailman/listinfo/osflash_osflash.org _______________________________________________ osflash mailing list [email protected] http://osflash.org/mailman/listinfo/osflash_osflash.org
