Re: [stella] First steps

Subject: Re: [stella] First steps
From: "Glenn Saunders" <cybpunks@xxxxxxxxxxx>
Date: Mon, 10 Sep 2001 12:08:57 -0700
Have you tried setting x=0 to the CENTER of the screen, rather than the left?
If you do that, you can use mirrored PF quite easily. This might raise other
issues though....

It's mostly a matter of mental visualization.

I "think" in terms of a coordinate space where 0,0 is at the top left of the screen and the scanline counter incrementing downward. It's been confusing as it is dealing with this decrementing scanline counter. I hate that, but it seems to be the standard way to do it on the 2600, having all the data upside down, probably because BNE is a quicker way to end a loop than testing for a given maximum value.

BTW, for those in the know, with rotating sprite games like Combat and Indy500, how many of the 16 frames of sprite rotation animation are stored in ROM? You could get by with only storing 5 frames for 1/4 of the rotation, and then using the sprite flip register for the other half, and scanning in reverse to flip it vertically. I'm assuming that these games store 9 frames in order to simplify the kernel, only taking advantage of the sprite flip.

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