CompuServe Messages

Screen centering affects how much "free time" there is available at the beginning and end of each scan line. Sprites are moved and displayed during those time periods (end of line). When you re-center, you can easily reduce the amount of free time at the end of the scan line where the sprites are handled by the custom hardware such that there is not enough to do it right. As a result, the hardware starts the job, gets partway in, and then loses it's marbles as far as that sprite goes. Display of bitplane (normal screen data) has a much higher hardware priority, and so the sprite generator is clobbered, and bitplane display begins. That's it in a nutshell. Ben Amateur Radio Callsign is A A 7 A S