Re: A82: questions from a low intermidiate level programmer
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Re: A82: questions from a low intermidiate level programmer
>>1. If you wanted to make a scrolling screen, (like for Pocman for the 85, or
>>Srqxz for that matter) what would be the easiest way to do it? Could you just
>>make a huge string of ones and zeros stored at the end of the program and
>>then store a certain section of it into the graph_mem to display, using
>>ROM_CALL(DISP_GRAPH) or is that immpossible.
>
>The is a somewhat feasible but very inefficient way of doing it. A better
>way to do it would be to store the level like this:
>
>.db 1,1,1,1,1,1
>.db 1,0,0,0,0,1
>.db 1,4,0,2,0,1
>.db 1,1,1,1,1,1
>
>with each number corresponding to a different block in your game. Then you
>need to draw your screen using that data. In order to scroll (depending on
>how many/which ways you want to scroll) you need to either shift the screen
>left, right, up or down. For the left and right scrolling, look into the
>'rr' and 'rl' instructions and for the up and down scrolling, 'ldir' and
>'lddr' are your best bet. Once you have scrolled, you will be left with
>some garbage on the edge of the screen (which edge depends on which way you
>scrolled) that needs to be filled in with the appropriate sprites. A good
>way to do this is to use sprite clipping. There are some excellent routines
>written by Jimmy Mardell for his 85/86 game Sqrxz that clip sprites. (They
>need to be modified slightly, but the modifications aren't terribly difficult)
Isn't this how it's done on the NES? I read some pecs on it somewhere that
made mention of a "Pattern Table", and there is definate repitition of
background (& foreground) objects.
Robert Glass rglass@lab.Lander.edu dash_squirrel@geocities.com
http://www.geocities.com/Yosemite/3542 http://iceweasel.home.ml.org
The SPC quote of the week:
Big Cheese offering suggestions on how to get rid of a dragon:
We could elect the dragon vice-president, that way we'd never hear from it
again.