Re: [stella] Re: the big sprite

Subject: Re: [stella] Re: the big sprite
From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 06 Apr 1998 17:11:50 +0200
At 17:17 05.04.98 GMT, you wrote:

>(There wouldn't be a cycle penalty if some of the pointers point to
>different pages, right?  As long as we never index across a page boundary?)

That's right. We just need to make sure, that all columns for
a certain set of animation frames would fit into one 2kb bank,
since we can't switch the bank during display.

>That's enough to load/store a color (8 cycles), and maybe even check and
>turn on or off the ball or do a little bit of playfield.  The two-sprite
>kernel wouldn't have support for projectiles - perhaps the ball could be
>used for that?

Colour changes would be possible, but they would be 11 cycles, since
we have to change colour for both player graphics. The ball and the
playfield thing would be a bit difficult, since conditional branches
would mess up the timing. Also, since the players are moveable, the
writes to PFx or ENABL would occur at different cycles in the scanline.
That means graphics left of the player would be affected one line
earlier than graphics right of the player, which would look a bit 

Ciao, Eckhard Stolberg

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