At 21.50 04/05/00 -0500, you wrote:
>Here is an example. Air-Sea battle. I don't know if they used collision
>detections, but here is how it may be done:
>
>Assume that each balloon/plane/boat is P0, reused every (let's say, I
>didn't count) 16 or so scan lines. In order to tell which one of the
>targets is hit, the program needs to read CXM0P and CXM1P every 16 lines
>and then after dealing w/ that(probably saving to RAM), punching CXCLR.
>This process needs to be done between every vertical segment that you want
>to check for collisions between.
There's a simpler way of doing this: remember that in a game like Air-Sea
Battle each (pseudo)sprite has a fixed vertical position. You can check for
collision between the missile and P0 just once in a frame, and select which
target was hit just from the y-coordinate of the missile! misslY/16=index
of the target that has been hit.
I used a more elaborate version of this concept for Oystron (where there
are two gun shots and targets that are pseudo-sprites in multiple copies).
Ciao,
P.
--
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
