Subject: Re: [stella] video memory From: Glenn Saunders <krishna@xxxxxxxxxxxx> Date: Thu, 11 Sep 1997 23:29:52 -0700 (PDT) |
On Fri, 12 Sep 1997, Mike St. Clair wrote: > Um, somebody *please* correct me if my interpretation is correct, but > these comments seem to me to say that the ram+rom of a 2600 game is larger > than the screen buffer/display ram of a modern console. No, what I'm saying is this: The 2600 can't really do much thinking when it is generating the display (well, a little, but not much). It has to decide what to do on the next frame mostly during the unused portion of the display, or the vertical blank interval. So for all intents and purposes, the 6507 hand-feeds the TIA chip during the visual portion of the display, and any data that it needs could be considered "video memory" since the machine is concerned totally with generating the display, scanline by scanline, during the visual portion of the code. Some games require 4, 8K or more worth of data and instructions by the time that individual screen alone goes from top to bottom. I'm not talking about game logic and other game-think. I'm just talking about banging the 2600 hardware registers. So the lack of "video memory" can be misleading. My point is that if the 2600 is generating a very busy display, with many different sprites and different shapes, and frames of animation, that it could very well be accessing more "pseudo video memory" if you call it, than its peers like the Astrocade had built in. You can not create complex displays without using more memory than the 2600 provides. Even Combat requires more than the 2600's internal scanline buffers to generate its displays (not much, but some). The 2600 is a scanline based system (maybe the only one). It's memory requirements for the individual scanlines themselves are MINISCULE, and it requires very modest resources to create simple displays with simple reflected playfields, but the resources it can require over the course of a whole screen redraw can be HUGE if you want to make a decent looking display like Solaris where the screen is filled with nothing but reused single-line-res sprites with color changes on every scanline with many frames of animation/scaling. You can't get something for nothing... -- Archives updated once/day at http://www.biglist.com/lists/stella/archives/ Unsubscribing and other info at http://www.biglist.com/lists/stella/stella.html
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [stella] video memory, Greg Miller | Thread | Re: [stella] video memory, Nick S Bensema |
Re: [stella] video memory, Greg Miller | Date | Re: [stella] video memory, Nick S Bensema |
Month |