>
>I suspect that a common technique for putting more objects on the screen
>must be based on the multiple copies feature of Atari 2600 sprites.
>
>Think about Activision Plaque Attack enemies (or a lot of other shooters),
>where you have groups of three aliens:
>
> X X X
Space Invaders, and I think Galaxian, used groups of six, or rather,
two groups of three.
This is a perfect opportunity to make your life simpler through tables.
It would probably take 16 bytes; 14 if you take it as given in your
code that 000 means nothing shows up... very wise, since there is no
NUSIZ register for "nothing shows up".
I'm pretty sure Okie Dokie does something similar.
>And what about explosions? If you want to use the same sprite for a group
>of aliens and their explosions, I think that a pattern change "on the fly"
>is needed, as said above. Or maybe you might use the other sprite to draw
>the exploding alien. Or just let them disappear... :-)
Or the missile. Of course, Space Invaders did id the hard way, and I
suggest you check the source code to figure out how they pulled
that one off.
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