[airstrike] Airstrike engine questions?

[Ulf Ekström]

On Sun, Apr 25, 2004 at 07:14:17PM +0300, Eero Tamminen wrote:
> Hi,
> 
> While porting the old objects back to CVS version, I got a few questions:
> 
> - What is Airstrike frame rate?
>   (so that I can calculate the alarm times)

30 ms/frame
 
> - What are the differencies between different sprite groups:
>   - bg_mech_group

Deprecated, should be removed. I had forgotten about it.

>   - mech_group

All sprites using the mechanics code in collisions etc (mech_sprite_t),
all player sprites.

>   - bullet_group

Bullets. Tested for collisions against background and mech_group.

>   - effects_group

Explosions etc. Have no effect on gameplay.

>   - foreground_group

Effects that are in from of effects, like the clouds. We don't want
the plane to make smoke behind the cloud, but that the smoke will be
in front of it.

>   - ui_group

For user interface elements that are also sprites. Maybe we should deprecate
this one, it's not used.

>   ?
> They are painted on screen in this order, but is there any other difference,
> e.g. performance wise?

Collisions are only tested 

mech vs. mech
mech vs. bullets.

> I was also wondering whether it would be worthwhile to change
> sprite_alarm() to accept (e.g.) milliseconds instead of frames:
> - Makes programming objects easier (game can calculate instead of
>   the programmer when the alarm should go off)
> - If framerate is going to change, it needs to be changed only in one place

Go ahead if you like, it might be better for the reasons you state. 

> Would there be any problems with this?  E.g. rate_limit() should probably
> be changed then too.

No, please go ahead.

Ulf