Few mathsey problems

phaxx

I'm writing a little game at the moment, and have become kind of stuck. I'd be grateful for any help anyone can provide.

It's a little windows Spacewar! clone, and I need some kind of collision-detection, because it's pretty damn useless otherwise!

First problem is to know when a missile has hit a spaceship, or to put it another way, when a given point is within a given circle.

The information I'd have for this is:
mX,mY, missile x and y co-ords

sX, sY, spaceship center co-ords, and sR, radius of the circle.

I really have no idea how to go about this...

The other problem is the lasers, I need to know if a line goes through a given circle. Could probably adapt the solution of the above problem?

Information available for this is the x,y values of both points of the line (laser) and the circle x,y and radius as above.

Please help, game is useless without collision detection

nesf

It's not complicated really, you could just write a subroutine to check if either if
the distance (mx,my) to (sx,sy) is = sR

If it is then a missile has hit. You can use simple junior cert level geometry for this.

You could write a more complicated sub for the second prob, where you check the perp distance from the line to the centre of the spaceship circle, leaving cert formula, if this is <= sR then you got a hit.

Any help to you?

Bob the Unlucky Octopus

Moved to programming- the math folks there could probably help you more

Bob the Unlucky Octopus