Pong w/ classes

[TheOneTrueGod]

Since theres SO many pong programs out there, I decided to do something different to demonstrate the power of classes. At first glance, the game doesn't look like much, it just looks like normal pong, but in this version, it would take like 5 lines to do something like, add 5 extra balls, give each player two paddles, etc...

code:

class Ball     export Create, Manage, Scored, ReverseXSpeed, X, Y     var x, y, xs, ys : real     procedure Create (x_, y_ : real)         x := x_         y := y_         xs := Rand.Int (100, 200) / 100 * (Rand.Int (0, 1) * 2 - 1)         ys := Rand.Int (100, 200) / 100 * (Rand.Int (0, 1) * 2 - 1)     end Create     function X : real         result x     end X     function Y : real         result y     end Y     procedure Manage         if y + ys > maxy or y + ys < 0 then             ys *= -1         end if         x += xs         y += ys         drawfilloval (round (x), round (y), 5, 5, black)         drawoval (round (x), round (y), 5, 5, grey)     end Manage     function Scored : int         if x < 0 then             result 1         elsif x > maxx then             result 2         end if         result 0     end Scored     procedure ReverseXSpeed (newX : int)         x := newX         xs := xs * -1 * Rand.Int (130, 160) / 100         ys := ys * Rand.Int (110, 120) / 100     end ReverseXSpeed end Ball var pervasive keys : array char of boolean class Paddle     import Ball     export Create, Manage, CheckForCollision     var x, y : int     var speed, ysize, xsize : int     var UPKEY, DOWNKEY : int     procedure Create (x_, y_ : int, UPKEY_, DOWNKEY_ : int, xsize_, ysize_ : int)         x := x_         y := y_         UPKEY := UPKEY_         DOWNKEY := DOWNKEY_         speed := 3         ysize := ysize_         xsize := xsize_ div 2     end Create     procedure Manage         if keys (chr (UPKEY)) and y + ysize < maxy then             y += speed         end if         if keys (chr (DOWNKEY)) and y > 0 then             y -= speed         end if         drawfillbox (x - xsize, y, x + xsize, y + ysize, grey)         drawbox (x - xsize, y, x + xsize, y + ysize, black)     end Manage     procedure CheckForCollision (var b : ^Ball)         if b -> Y > y and b -> Y < y + ysize and b -> X > x - xsize and b -> X < x + xsize then             if b -> X < x then                 b -> ReverseXSpeed (x - xsize - 1)             else                 b -> ReverseXSpeed (x + xsize + 1)             end if         end if     end CheckForCollision end Paddle var b : array 1 .. 1 of ^Ball var p : array 1 .. 2 of ^Paddle var leftScore, rightScore : int := 0 new Paddle, p (1) new Paddle, p (2) new Ball, b (1) p (1) -> Create (5, maxy div 2, ord ('w'), ord ('s'), 5, 50) p (2) -> Create (maxx - 5, maxy div 2, ord ('w'), ord ('s'), 5, 50) b (1) -> Create (maxx div 2, maxy div 2) View.Set ('offscreenonly') loop     Input.KeyDown (keys)     locate (1, maxcol div 2 - length (intstr (leftScore)))     drawline (maxx div 2, maxy, maxx div 2, 0, black)     put leftScore, ":", rightScore         for i : 1 .. 2         p (i) -> Manage         for j : 1 .. upper (b)             p (i) -> CheckForCollision (b (j))         end for     end for         for i : 1 .. upper (b)         b (i) -> Manage         if b (i) -> Scored not= 0 then             if b (i) -> Scored = 1 then                 leftScore += 1             elsif b (i) -> Scored = 2 then                 rightScore += 1             end if             b (i) := b (upper (b))             b (upper (b)) -> Create (maxx div 2, maxy div 2)         end if     end for     View.Update     Time.DelaySinceLast (25)     cls end loop

And heres a sample of what you can do with like 3 lines of change.
(Just replace everything after the end of the classes with this code)

code:

var b : array 1 .. 5 of ^Ball var p : array 1 .. 6 of ^Paddle var leftScore, rightScore : int := 0 for i : 1 .. upper (p)     new Paddle, p (i) end for for i : 1 .. upper (b)     new Ball, b (i) end for %Left Player p (1) -> Create (5, maxy div 2, ord ('w'), ord ('s'), 5, 50, 4) p (3) -> Create (5, maxy div 2, ord ('s'), ord ('w'), 5, 50, 4) p (5) -> Create (maxx div 4, maxy div 2, ord ('w'), ord ('s'), 15, 50, 4) %Right Player p (2) -> Create (maxx - 5, maxy div 2, ord (KEY_UP_ARROW), ord (KEY_DOWN_ARROW), 5, 50, 4) p (4) -> Create (maxx - 5, maxy div 2, ord (KEY_DOWN_ARROW), ord (KEY_UP_ARROW), 5, 50, 4) p (6) -> Create (maxx div 4 * 3, maxy div 2, ord (KEY_UP_ARROW), ord (KEY_DOWN_ARROW), 15, 50, 4) for i : 1 .. upper (b)     b (i) -> Create (maxx div 2, maxy div 2) end for View.Set ('offscreenonly') loop     Input.KeyDown (keys)     locate (1, maxcol div 2 - length (intstr (leftScore)))     drawline (maxx div 2, maxy, maxx div 2, 0, black)     put leftScore, ":", rightScore     for i : 1 .. upper (p)         p (i) -> Manage         for j : 1 .. upper (b)             p (i) -> CheckForCollision (b (j))         end for     end for     for i : 1 .. upper (b)         b (i) -> Manage         if b (i) -> Scored not= 0 then             if b (i) -> Scored = 1 then                 leftScore += 1             elsif b (i) -> Scored = 2 then                 rightScore += 1             end if             b (i) := b (upper (b))             b (upper (b)) := nil             new Ball, b (upper (b))             b (upper (b)) -> Create (maxx div 2, maxy div 2)         end if     end for     View.Update     Time.DelaySinceLast (25)     cls end loop

[Cervantes]

Good stuff. It really does my heart good to see more OOP code floating around the Turing forums than there was before.

One suggestion I have, however: Instead of making keys a pervasive variable, you could pass it in as a parameter to Paddle#Manage. Global variables are a pretty evil thing.

[TheOneTrueGod]

I've heard that several times, but i've allways wondered why? They detract from modularity, I believe, but somehow, I doubt that someone's going to be taking my paddle class and using it anyways .