#2948 - jerky - Fri Feb 14, 2003 11:40 pm
hi there, nothing special about mode 2 except that's what i'm using. so you know i'm using a tile background (synonamous with text bg?), writing 16 bits a time, 256 unique tile limit, etc.
short is, i'm getting flicker, a visual artifact. every 8 pixels i reset my scroll back 8 pixels and completely write over the vram map with a new map advanced 8 pixels - primitive scroller n'est-ce pas?
when i do this transition, i see a flicker of the "new map" with the old scroll setting, before it is properly redrawn with the reset scroll.
first question: is this a vsync problem? am i not writing fast enough between redraws?
if so, how can i write faster? i see dma posts, but how do i enable dma - currently i have my map in a linear array and copy right into vram?
lastly, my map is 64x64 tiles = 4K vram (right?). is it best to draw the "new" map to a different 4K screen base, and then swap pointers?
appreciatively j
short is, i'm getting flicker, a visual artifact. every 8 pixels i reset my scroll back 8 pixels and completely write over the vram map with a new map advanced 8 pixels - primitive scroller n'est-ce pas?
when i do this transition, i see a flicker of the "new map" with the old scroll setting, before it is properly redrawn with the reset scroll.
first question: is this a vsync problem? am i not writing fast enough between redraws?
if so, how can i write faster? i see dma posts, but how do i enable dma - currently i have my map in a linear array and copy right into vram?
lastly, my map is 64x64 tiles = 4K vram (right?). is it best to draw the "new" map to a different 4K screen base, and then swap pointers?
appreciatively j