Subject: Re: [stella] VDEL... From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx> Date: Sun, 24 Feb 2002 16:38:41 +0100 |
> >With VDEL you can update one > >of the players at anytime you want during the two > scanlines. > > Hm... how would that work? Could you post some little > example? I don't have an example myself, but you can look at the commented Combat code, which uses this method I think. Remember how VDEL works. There are actually two graphics registers for each player (GRP0-A, GRP0-B, GRP1-A and GRP1-B) and VDEL only selects whether to use the A or the B register for the output. Whenever you write something to the GRP register of one player this data gets written to the player's A register. But at the same time the data from the other player's A register gets copied to the corresponding B register. So if you update the graphics for both players on alternating scanlines, and turn on VDEL for only one of them, then both players will have their display changed in the same scanline. By chosing which players VDEL is turned on, you can get single line positioning precission (but only double line display resolution) even with a two line kernel. Ciao, Eckhard Stolberg ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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