Re: [stella] DD Dead end?

Subject: Re: [stella] DD Dead end?
From: "Glenn Saunders" <cybpunks@xxxxxxxxxxx>
Date: Thu, 08 Nov 2001 13:14:42 -0800

Are you sure that my LMNF kernel can't be adapted for DD?

I thought LMNF was a single-line kernel for one thing, and it had horizontal restrictions on the missiles. I'm not even worrying about tearing problems right now, but ultimately I will. If it takes me up to half the width of the kernel to update the width register for the missile, then depending on the missile X position, the width could inherit itself from the previous line on the left half, then tear in the middle, then be correct, as it moves from left to right. I can probably find a way to work around that if I get that far.

What's killing me is the playfield stuff. If I didn't have a dynamic playfield I'd probably have enough time. The playfield overhead involves not only the load/stores but the looping logic to index through all the tombstone graphics.

I guess I should try to disassemble Super Challenge Football again but I can tell it's got a very different kind of kernel just by looking at it.

If you look closely, it appears as if it's only generating one player and one missile per scanline, and it's staggering them. You never see two missiles or two players on the same scanline. That results in somewhat coarse movement. I can probably tolerate that with the pedestrians but I'd prefer not to do that with the cars. So that's why I'm doing P0 and P1 on the same scanline and using VDEL where necessary to get them on even/odd lines.

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