Subject: Re: [stella] 'Look Ma No Flicker' revisited From: Chris Wilkson <ecwilkso@xxxxxxx> Date: Fri, 31 Aug 2001 01:17:09 -0400 (EDT) |
On Thu, 30 Aug 2001, Erik Mooney wrote: > On Wed, 29 Aug 2001 20:10:05 -0700, you wrote: > > >>SC Football already definitively does it, so you aren't really doing > >>anything strictly new technically. More so the challenge here is to create > > > >I tried disassembling SC Football and didn't get that far. Huge chunks of > >"data" which I knew had to be code and not knowing what to do with it. > > > >>believable sprite shapes within the constraints of the missile objects. > > > >I already attempted as much that in the mockup images. I thought it looked > >somewhat Berzerk-like and acceptable. > > Those look okay, but they're only one frame of animation each; keep going. > :) > > >This is a real newbie question, but what's the best approach in the middle > >of the kernel to answer all these scanline-state questions, namely: > > > >Am I on a scanline that requires P0, if so, which address offset from the > >top of P0 do I pull the graphics from? > > > >Am I on a scanline that requires P1, if so, which address offset from the > >top of P0 do I pull the graphics from? > > Using Supercharger or Superchip RAM, there's a very elegant solution to > this. Simply have a 100-byte (or however many iterations your kernel goes > through) zeroed block of RAM. Offscreen, copy the sprite data into the > proper place into the 100 bytes, and every line in the kernel all you need > is an indexed load and zeropage store! (Works for your missile objects > too although you need to separate the NUSIZ and HMOVE data.) > > Sadly, even Superchip RAM isn't enough to do that for more than one player > object. Supercharger or Megacart RAM, on the other hand, could. > > Isn't there one of the M-network banking schemes that has 2K of RAM? That > could pull this off and make it playable on current emulators (SC is but > Megacart isn't.) I'd like to see a game come out of this list that goes > beyond the standard 4k cart or SC formats. If you really want to push the > 2600's limits... > > >I have a hard time figuring out how I can write the above code in the tiny > >amount of time one is given between WSYNC and the first playfield rewrite. > >Once the playfield starts rewriting there isn't going to be any time to do > >anything else until after PF1 on the right side is stored, which only leaves > >a little time left before you've reached cycle76. > > > >Since I'm only doing double-line res, I can unroll the kernel into a > >line-pair and only ask relevant questions about one player at a time, since > >even if they are supposed to appear on the same scanline, VDEL will make the > >adjustment to line them back up. But even then, it seems like there isn't > >enough time to do all this processing. > > Well, first you need to figure out exactly how you're writing the > playfield code, then you'll know exactly how many cycles you have to do > the players. Get your playfield functional, then we'll all have a go at > optimizing it. > > >Once I can get beyond this critical-section of the code, I think the rest is > >going to be a piece of cake in comparison. > > It's a piece of cake to code but not necessarily to get up the motivation > to do it. I lost interest in INV once the technical parts were done. > > - > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > Unsub & more at http://www.biglist.com/lists/stella/ > - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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