John Fraser Computer Contest Club

"Traditional" pong games check collision to see if the x and y cordinates of the ball of less than zero or greater than the max value of that length. This is another way to do it, via whatdotcolor. It checks to see if the next pixel is a certain color. Of course, using this method you must have solid color objects and no jpeg, bmps etc.

View.Set ("graphics: max, max")

View.Set ("offscreenonly")

var x, y, vx, vy : int := 1

var rad : int := 10

x := maxx div 2

y := maxy div 2

loop

cls

Draw.Box (0, 0, maxx, maxy, black)

Draw.FillOval (x, y, rad, rad, blue)

View.Update

x := x + vx % add velocities

y := y + vy

delay (5)

% check if the ball move offscreen by detecting if the next pixel is black

% the black box is drawn as a boarder, if the next pixel is black

% you know you are about to go offscreen, so reverse the velocity

if View.WhatDotColor (x, y + rad) = black then

vy *= -1

elsif View.WhatDotColor (x, y - rad) = black then

vy *= -1

end if

if View.WhatDotColor (x + rad, y) = black then

vx *= -1

elsif View.WhatDotColor (x - rad, y) = black then

vx *= -1

end if

end loop