Subject: Re: [stella] Gunfight 2600: Descissions had to be made From: Manuel Polik <manuel.polik@xxxxxxxxxxx> Date: Tue, 06 Mar 2001 10:03:52 +0100 |
Erik Mooney wrote: > >The next step I'll work on is the weapons system. Continuing with the > >playfield right now doesn't make sense, since I just don't now how many > >RAM is left after I'm done with the weapons. (I need at least need 2 > >bytes of X/Y coordinates, plus one byte direction + one byte lifetime > >per bullet, so handling 12 bullets for example would eat up a minimum of > >48 bytes RAM...) > You don't need 8 bits each for direction and lifetime. The direction is > only 8-way right? Uhm... well, normally yes. But I'm thinking about 2- and/or 3-way guns, which would introduce some more angles to take care about. > That's only 3 bits for direction. I'm not sure how > long the bullets last, but 6 bits gives you over one second at 60 fps. That's something I have in mind. The trick I'll do is: Decrementing the bullet life-time not every frame, but only every 8th or so. > Can't quite compress it to one byte per bullet which would be convenient, > unless you have half-second bullet lifetimes, or run the bullet processing > only every 2 or 3 frames With the little trick above, I can process the bullets every frame and still have a big enough lifetime value. But I can display only three bullets per frame, so I have to flicker them obviously. I just have to test to which degree this is acceptable, 12 bullets might already be too much, so I might come down to a total of 8 or 6 (which would then render 3-way shots impossible... at least for both players at once :-)) > I'm not quite sure of the behavior of the bullets - do they bounce or > anything? If not, you're storing redundant information somewhere in the > X/Y/lifetime bytes. Yes, they are intended to bounce, from obstacles as well as from screen borders. > >Please comment on the new demo. I hope it works fine for both players, I > >just had no second player to test if the players can interfere with each > >other during some weird Joystick movements :-) > Not sure what comments you want to see, but it does look good. Exactly the comments you just sent. Thanks! > Hope > there's time to load some playfield data instead of storing what looks > like the scanline counter. Currently there's still 24 NOPs in the second scanline, which should be enough for displaying some fine playfield obstacles. At least I hope so. I just need some 20-30 bytes of RAM left in the end to make 'em shootable. We'll see how it works out :-) Greetings, Manuel - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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