----------------------------------- upthescale Sat Apr 01, 2006 6:57 pm Pong ----------------------------------- i wanna make a pong game, but how do i do it so when the ball withs the edge of the screen, it will bounce away randomly, liek i don't want to set coordinates for the wohle game i want it no random ----------------------------------- do_pete Sat Apr 01, 2006 7:00 pm ----------------------------------- You would multiply your X speed variable by -1 ----------------------------------- upthescale Sat Apr 01, 2006 7:01 pm ----------------------------------- can u make a program quicktime of a ball bouncing randomoy arond the screen? ----------------------------------- Cervantes Sat Apr 01, 2006 7:02 pm ----------------------------------- "Randomness" can be achieved by using the Rand.Int function. Do you really want it to bounce randomly off a wall, though? That's not how collision works in this universe of ours. It's not random. The angle of incidence equals the angle of reflection. This is most easily achieved if you have x and y components to your ball's position and velocity, and if the wall it is bouncing off of is parallel to either the x or y axis. If it bounces of a horizontal wall then reverse the y velocity else if it bounces off a vertical wall then reverse the x velocity end if ----------------------------------- do_pete Sat Apr 01, 2006 7:04 pm ----------------------------------- Huh? What are you trying to say? ----------------------------------- upthescale Sat Apr 01, 2006 7:06 pm ----------------------------------- doesn't werk var x, y : int randint (x, 1, 500) randint (y, 1, 200) loop drawfillbox (x, y, x + 30, y + 30, 7) delay (12) drawfillbox (x, y, x + 30, y + 30, 0) x := x + 2 y := y + 2 if y > 420 then exit end if end loop loop drawfillbox (x, y, x + 30, y + 30, 7) delay (12) drawfillbox (x, y, x + 30, y + 30, 0) x := -x end loop ----------------------------------- Cervantes Sat Apr 01, 2006 7:13 pm ----------------------------------- It works. You've just done it wrong. ;) Why did you exit your loop when the ball collides with a horizontal wall? That's not what you want to do. You want to reverse it's vertical velocity. Furthermore, in the last portion of your code (the second loop), x := -x is not going to reverse the velocity of the ball. It's going to flip the ball from one side of the y axis to the other. Finally, your code exits the first loop when it bounces off a horizontal wall, then you go in the second loop attempting to modify the horizontal velcoity. The horizontal velocity doesn't change when a ball bounces off a horizontal wall. Really, this isn't hard. Put a little thought into it, and I'm sure you'll understand it a whole lot better. Feeding you the answers isn't going to help you understand anything as much as if you figured it out mostly on your own. ----------------------------------- upthescale Sat Apr 01, 2006 7:14 pm ----------------------------------- i've been trying fer weeks now can u plz just fix it and paste it ----------------------------------- do_pete Sat Apr 01, 2006 7:18 pm ----------------------------------- We don't do people's homework ----------------------------------- upthescale Sat Apr 01, 2006 7:20 pm ----------------------------------- im done turing i finished it last semester ----------------------------------- Cervantes Sat Apr 01, 2006 7:33 pm ----------------------------------- Trying for weeks, but on what? You've already been told basically how to do it. Begging for people to tell you the answers is a terrible attitude. ----------------------------------- upthescale Sat Apr 01, 2006 7:34 pm ----------------------------------- but when i puty x:=-x like u told me, the box just stays n the same position ttwitching like a mad man ----------------------------------- [Gandalf] Sat Apr 01, 2006 7:55 pm ----------------------------------- Create a vx and vy variable (velocity in x direction, velocity in y direction), and work with those instead of directly with the x and y vars.