Re: [stella] Collaboration

Subject: Re: [stella] Collaboration
From: "Glenn Saunders" <cybpunks@xxxxxxxxxxx>
Date: Fri, 17 Jan 2003 13:09:28 -0800

I understand. If we can't find a way for different colors , then how about blinking (not flickering!) grenades? With a 50% on/off ratio, we could show two grenades without having to reposition them inside the kernel.

By giving the grenade objects a unique color I can do cool stuff like have different kinds of powerups based on the color so it can serve many purposes. There is also no reason the zombies have to spawn it. It could show up spontaneously. I could use those scanlines for grenades and powerups. By making grenades 1-pixel-width and powerups 4-pixel-width, although I can't have both on screen at once, I can still have the two more discrete object types in the game.

A good way around the ball problems, I think would be to use a single playfield bit for the grenade. You just lose a little horizontal positioning accuracy and you can't smoothly animate it. But it might be a lot simpler to just do that than to try to use a sprite there. There might be enough time to give it a unique color and allow for a grenade on every row that way.

Of course, that eats up more RAM that way. If only one bit is going to appear on any given grenade line then it might be possible to just reserve a single byte for each grenade line, with 4 different kernels that selectively blank out the other playfield registers. Depending on the X position of the grenade, the proper kernel would be called that uses the byte for the proper register/instance of register.

1---- 00000000 -------- -------- -------- ---- NO GRENADE (blank byte)
1---- 00001000 -------- -------- -------- ----
2---- -------- 00001000 -------- -------- ----
3---- -------- -------- 00001000 -------- ----
4---- -------- -------- -------- 00001000 ----

That way you'd only need 9 or 10 bytes of RAM to allow for one grenade active for every row at the same time, more if the grenades can be of different types (hence different colors, you'd need RAM for that unless you burned the color as an immediate load into more kernel variations).

With some positioning limitations in kernel variation 1 or 4 it should be possible to change the playfield color register for the grenade, don't you think?

If we use playfield, I can think of at least one creative use for the ball. We could just draw a simple straight line down the screen. Setup for the ball would occur during the border zones so that should be plenty of time. This could be a kind of barrier powerup or something that can be used to trap zombies, keeping them from reaching the other half of the screen. Imagine if that barrier could be "nudged" by the cars when you bounce against it. Lots of things you can do with that.

How does that sound?

The combination of having an independently colored playfield bit inbetween tombstone zones and an independently positioned ball line should provide all the flexibility we need to create plenty of variation in gameplay.

We can even leave the ball "on" all the time if it helps simplify the kernel and just position it on top of the safe zones when it's not needed.

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