Subject: Re: [stella] Games to be shown in the documentary From: Erik Mooney <emooney@xxxxxxxxxxxxxxxx> Date: Wed, 7 Jan 1998 09:04:19 -0500 (EST) |
> I had thought of this, it seems a good idea. I'm just about a little scared, > because I'll have to change the code that 'eats' the shields.. any suggestion? > P. ok... looking at my code and dredging up memories (*yeech* that code is a mess!), I find that the part that actually removes the pixel from the shield is after label SH1 in the code. Since you're still only removing one pixel from memory at a time, you don't need to change that part... Currently, the shields are stored bottom-to-top in the array at $A0 (bottom line of leftmost shield is at $A0, top line at $A7, bottom line of second shield at $A8, etc). What I *think* you need to change is, right before the label SH0 (that's a zero), add an LSR between the AND #$F8 and the following TAX. That'll limit the shield-destroying routine to four rows. Then, you need to change the draw-shields routine so that the shields start at Shields, Shields+4, Shields+8 and Shields+12 instead of the current Shields, Shields+8, Shields+16, and shields+24. You also need to make that routine display each line twice, but that's easy - change the LDY #7 to LDY #3, and do DEY every other line instead of every line. And you need to change the shield-initialization code at the end of subroutine BoardInit to only write four bytes to each shield instead of eight. That *should* do it and get you 16 bytes of RAM. Have fun :) -- Stella list is Administered by krishna@xxxxxxxxxxxx <Glenn Saunders> Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/stella.html +-shameless plugs-------------------------------------------------------+ | Stella documentary at http://www.primenet.com/~krishna | | Nick's VCS links via http://www.primenet.com/~nickb/atariprg.htm | | Write the best game, win framed autographs of famous Atari alumni!! | +-----------------------------------------------------------------------+
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [stella] Games to be shown in t, Piero Cavina | Thread | Re: [stella] Games to be shown in t, Piero Cavina |
Re: [stella] Games to be shown in t, Erik Mooney | Date | RE: [stella] Games to be shown in t, A. |
Month |