Wow... Haven't thought about double-buffering in a while :0) I have seen the same "stair-step" pattern myself, particularly when flipping through a series of bitmaps in an un-moving member. It happens on some video cards, not on others. Hence, I have blamed it on the implementation of the video driver.
However, is this what you are talking about Court? From your initial posting, I got the feeling that your issue was with the perceived motion of the image itself, be it a bitmap or a solid block of color. First of all, is my perception correct? If so, are you doing any fancy easing with the animation? From what I have seen, sometimes interpolating an image only using whole pixel values can produce chunky results, especially if you are trying to finesse it. If I am wrong, just ignore all this spewing of ??? Thanks, ~Mathew -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kerry Thompson Sent: Tuesday, August 12, 2003 5:09 PM To: [EMAIL PROTECTED] Subject: RE: <lingo-l> animating scaling of sprites > In my opinion this effect is due to the frequency difference > of the animation and the graphics adaptor. > > Director or Flash could be running let's say at 13 fps, > whereas the graphics adaptor would run at 60 fps for example. Interesting theory, but I don't think it holds up in reality. The graphics adaptor will draw the screen at whatever refresh rate you set--we can use 60 Hz as a base rate. When it draws, it draws whatever is in the video card's current page memory. Director fills its part of that memory with whatever is on the stage (in a projector). Actually, it instructs Windows to display something, and Windows tells the video card driver what to draw, and the video card driver zaps the stuff into the video card's RAM. If Director is running at, say, 20 fps, it fills its part of the video ram 20 times per second. That process, though, takes microseconds, and it's unlikely to be interrupted part of the way through, simply because it's so fast. Also, most video cards have a paging system where it draws a page in a part of the ram that's not currently being displayed, then, when it's finished, it displays that page. It knows when a page is being updated, and it won't flip pages until the page is finished updating. Even if the video card did an update while Director was in the process of drawing a frame, the "stair step" would only be visible briefly, for 1/60th of a second until the next video refresh. So, there is another reason for the stair step effect. Not sure what it is, but I'm pretty sure of what it isn't. Cordially, Kerry Thompson [To remove yourself from this list, or to change to digest mode, go to http://www.penworks.com/lingo-l.cgi To post messages to the list, email [EMAIL PROTECTED] (Problems, email [EMAIL PROTECTED]). Lingo-L is for learning and helping with programming Lingo. Thanks!]
