CompuServe Messages

Rick: When you say you are going "to interlace", do you mean you simply flip the display into interlace, or are you doubling the screen height (from, say, 200 to 400 lines)? If you are running 4 bitplane graphics (16 color), and you change from a 640 x 200 to a 640 x 400 screen, most of the CHIP DMA will be used to move the screenbits out to video. In this environment, very, very few of the real sprites will be available for use by the vsprite software. The visual effect you are witnessing is the vsprite software running out of real sprites. I believe that it is unable to reuse a sprite until a scan line or two underneath its bottom raster line. Thus, if more than 2 or 3 appear together horizontally, some will simply not be there. As the sprites move vertically away from each other, they will flicker on. If this is indeed the problem you are seeing, I think you'll have to live with it. Of course, you COULD use BOBS instead. Ariel