Subject: Re: [stella] Built-in screen saver From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx> Date: Fri, 06 Aug 1999 14:14:15 +0200 |
At 00:06 06.08.99 -0500, you wrote: >Is this just a subroutine that is accessed in the "mainloop" (to use Nick >Bensema's playfield code)? Does anyone know what this code looks like, and >how it checks if a game is idle or not, and how long the game waits before >a screen saver mode hits? I haven't seen the actual code, but I think it works something like this: The early Atari games checked the COLOUR-B/W switch once per frame, so that they could set the colours apropriately. I think that they probably did some bit manipulation with the colour values before they were written to the TIA colour registers, if the game wasn't in play mode. I also think that they used one byte to tell if the game is in play mode. One bit toggles the mode and the other seven bits work as a counter for the next change to the colour modifier. This would result in a colour change about every two seconds, which seems to be what the games do. 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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