Kerry, I am not a computer hardware specialist, but I am QUITE sure my theory is correct.
Here's why: > The graphics adaptor will draw the screen at whatever refresh rate you set--we can use 60 Hz as a base rate. This is exactly what you can use for testing. Change the refresh rate and watch the result. As for my numerous tests: Whenever I changed the refresh rate, what I saw was what I expected in [my] theory. > 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 The important thing is that the graphics adapter takes its time to prepare or draw the image. I almost had written that it didn't matter how long Director takes to draw its image. But as a matter of fact it does! The video card takes quite long to get the image displayed. If Director too took so long, then you wouldn't get stair steps, but a gradient (which would be fine, because you wouldn't notice it!). You see stair steps, BECAUSE Director is so fast. If the resolution of the monitor was much higher than it is, and if you had the eye of a fly to be able to measure out the width of the step/gradient in a fraction of a second, then you could use that to calculate the time Director takes to fill the video ram. > 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. You think, 1/60th of a second is "brief"? When you take a photo, the flash light is visible for about 1/50,000 of a second. Don't you see it? I do! Ever watched a movie in the cinema? A scratch in a frame is displayed for 1/48 seconds. You see that VERY WELL. If you chose the frequencies the way that one is similar to the other or different by a multiple of a whole number, then you will see that the stair steps appear more or less in the same area of your monitor. If you chose them arbitrarily, the stair steps appear all over the monitor at random. Also, the stair steps are always horizontal, never vertical. Another evidence is that that if you increase the refresh rate of the video card, the effect is less visible. This problem bothers me quite a while and I am very keen of getting it solved. But unless someone comes up with a better, more plausible theory, I'll stick to mine. Michael -----Ursprungliche Nachricht----- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Auftrag von Kerry Thompson Gesendet: Dienstag, 12. August 2003 23:09 An: [EMAIL PROTECTED] Betreff: 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!] [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!]
