Collision of two moving entities

Check:
http://www.stickystudios.com/ftpJeroen/multipongtest3.exe (467kb)

I want to make a LAN pong game with some Arkanoid influences. Just a simple little game :-)

1) If you move the bat quickly it will not collide with the balls. Does anyone know how I can check like "Entitydistance", but then for rectangular objects?
The odd thing is; the balls collide properly, with Blitz collisions!

2) When you press the left mouse button, the camera turns, and the controls will be bad, since the Y-axis do not correspondent with the camera rotation. How can I possibly avoid this problem?

Thanks!

Jeroen

well simply check if the balls Z is higher than the one of the bat. If it is, check if its X and Y is within the size and location of the bat. additionally you culd add some drift, depending on the motion speed of the bat. This would work completely without collisions.

2: that's a tricky problem. If your camera switches to the other side, you can invert the x motion of the pad, but when the cam flys around like in a matrix scene, that's no good for the controls.

thanks! The problem is that the bat rotates based on user input. So, that makes it more complex.

Blitz has only sphere to something collisions, so perhaps you could check for other libraries or dll's like coldet...

It's a Pong game... he only needs sphere-to-something!

Except when the bat moves into the ball. ;)

There is some code in the archives which uses blitz collisions and will always produce the correct response .. In fact this would be perfect for you ..

http://www.blitzbasic.com/codearcs/codearcs.php?code=898

http://www.blitzbasic.com/toolbox/toolbox.php?tool=11
http://www.blitzbasic.com/toolbox/toolbox.php?tool=49

Bizarrely I did a Pong clone ages ago and it uses only one Collisions command (sphere to poly) for ball to bat collision and it works perfectly... I mean I've tested and tested it and can't make it fail. Yet when migrate the code to any other context, I start to see the normal OMG!-Two-Moving-Things!-Help-Me! Blitz problems with collisions not being caught - which is a shame as I was going to post it but there's no point now.

Sledge, I'm guessing that probably worked in your Pong game because the ball is constantly in motion so blitz can always see collisions as ball-to-bat. Just a guess, though.

Well I tried isolating it from the game to post and it just doesn't work reliably - I think I must've got lucky with the relative dimentions of the objects and the speeds/angles at which it is possible for them to collide. It's not applicable in general, though, so your earlier statement stands.