CompuServe Messages

<You mean writing a second page while waiting for the vertical retrace so you don't have to just sit and wait for the next one if it takes 2% too much time for a single screen draw?> Yes <Would you do this on another X-Page and then flip between 3 pages instead of 2?> Right again. <Also, what do you mean by "tearing"? You mean that (sometimes moving) horizontal line across the screen where you see one frame on top and the next frame on the bottom?> Three for three. <If what I said about triple buffering is right, how do you know when to jump out of your 2nd-page-draw and flip pages? Can you set up an interrupt that calls the page flipper during retrace? If so, how?> You wait until you finish drawing to the page, and then flip pages. You don't have to worry about when you flip pages, because the page flip will not take effect until verticle retrace. <And another thing – can't uou still do this in Mode 13?> You can do this in mode 13h. As you know, in mode 13h you are using system ram, that you copy to vram, instead of a true page flip. So you never know if you are blitting the screen during retrace. To solve this problem you have to sync the retrace with the timer so that you know approximately when a retrace will happen.