Re: [stella] 11 Invaders "Reloaded"

[christophertumber@xxxxxxxxxx]

(Sorry about that, I'm using a library terminal and it logs me out every 15 minutes)

Anyway, doing 11x5 in and of itself is not a big deal - Erik did it years ago, and Space Instigators did it as well (until I had to change it). There are also numerous other demos which display more than 13 sprites. The big trick is NOT displaying sprites. Specifically, leaving the space blank when aliens are killed off.

A big, big part of the Space Instigators code is to handle exceptions where you can no longer use the RESPn trick. Something like:

010_0_010

Where 0 is an RESP0 sprite,
1 is an RESP1 sprite
and _ is an empty sprite.

There are an awful lot of these, however at 9x5 it's still manageable. In the case above, the 0's would be done with RESPn trickery, while the 0 would be a double sprite set at (umm) medium (? off the top of my head) distance.

However, at 11x5 the number of exceptions is increased exponentially and some of them may not be possible to do at all. For example:

10_0_0_0_01

Is that even possible? The 0's would be RESPn trick, but is there a configuration of duplicated sprites that can span that vertical distance?

Anyway, I do wish you the best of luck, but I think from our previous emails you're really underestimating what's left - You've only just done the easy part (that was already done by Erik). The hard part is just coming up...



Chris...


(BTW - All the previous stuff about GRPn is irrelevant, the reason there are so many different kernals is one for each vertical position of the formation. At the time I couldn't come up with any other delay loop with 1 cycle of accuracy (ie: a delay between 0 to 11 cycles or whatever)


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