Pong help

[Travveh]

Well, I have my simple problem. I made pong, but It occasionally starts in an enless loop. It's 4-player pong on a 700x700 field with 200x200 boxes in each corner. The ball bounces by multiply the direction by -1. Help would be greatly aooreciated, as this class is over in a couple days.

[Remm]

Well, as we say to EVERY person who posts like this :
If you havent, check the turing tutorial about loops and for loops to see if you can find anything odd with your program.
Secondly, you would be best to give your source code or portions of your sorce code so we can have a look at the program too, and see what is wrong with it first-hand.
Also, since you know your program better than anyone, check your own loops and for loops to make sure all the exiting and whatnot is in order.

[Clayton]

could you post code plz, we cant really help u unless we can see what you are doing, remember to use [code] tags when posting code

[Travveh]

code:

View.Set ('graphics:700;700, position:middle;middle, nobuttonbar, offscreenonly, nocursor')   var x, y : int var mx, my, button : int var yd : int := -1 var xd : int := -1 var y1, y2 : int := 300 var x1, x2 : int := 300 var P1, P2, P3, P4 : int := 0 var speed : int := 0 var P1Color, P2Color, P3Color, P4Color : int := 0 var hit : int := 0 var key : array char of boolean var font : int := Font.New ("Viner Hand ITC:30:bold") var font2 : int := Font.New ("Comic Sans:20") var font3 : int := Font.New ("Arial:50") var Player1, Player2, Player3, Player4, again : string var P1Win, P2Win, P3Win, P4Win, Play : boolean := false randint (x, 200, maxx - 200) randint (y, 200, maxy - 200) procedure drawField     Draw.FillBox (0, 0, maxx, maxy, green)     Draw.FillBox (0, maxy, 200, maxy - 200, black)     Draw.FillBox (maxx, maxy, maxx - 200, maxy - 200, black)     Draw.FillBox (0, 0, 200, 200, black)     Draw.FillBox (maxx, 0, maxx - 200, 200, black)         if P1 = 0 then         Player1 := "0"     elsif P1 = 1 then         Player1 := "1"     elsif P1 = 2 then         Player1 := "2"     elsif P1 = 3 then         Player1 := "3"     elsif P1 = 4 then         Player1 := "4"     elsif P1 = 5 then         Player1 := "5"     elsif P1 = 6 then         Player1 := "6"     elsif P1 = 7 then         Player1 := "7"     elsif P1 = 8 then         Player1 := "8"     elsif P1 = 9 then         Player1 := "9"     elsif P1 = 10 then         Player1 := "10"         P1Win := true     end if     if P2 = 0 then         Player2 := "0"     elsif P2 = 1 then         Player2 := "1"     elsif P2 = 2 then         Player2 := "2"     elsif P2 = 3 then         Player2 := "3"     elsif P2 = 4 then         Player2 := "4"     elsif P2 = 5 then         Player2 := "5"     elsif P2 = 6 then         Player2 := "6"     elsif P2 = 7 then         Player2 := "7"     elsif P2 = 8 then         Player2 := "8"     elsif P2 = 9 then         Player2 := "9"     elsif P2 = 10 then         Player2 := "10"         P2Win := true     end if     if P3 = 0 then         Player3 := "0"     elsif P3 = 1 then         Player3 := "1"     elsif P3 = 2 then         Player3 := "2"     elsif P3 = 3 then         Player3 := "3"     elsif P3 = 4 then         Player3 := "4"     elsif P3 = 5 then         Player3 := "5"     elsif P3 = 6 then         Player3 := "6"     elsif P3 = 7 then         Player3 := "7"     elsif P3 = 8 then         Player3 := "8"     elsif P3 = 9 then         Player3 := "9"     elsif P3 = 10 then         Player3 := "10"         P3Win := true     end if     if P4 = 0 then         Player4 := "0"     elsif P4 = 1 then         Player4 := "1"     elsif P4 = 2 then         Player4 := "2"     elsif P4 = 3 then         Player4 := "3"     elsif P4 = 4 then         Player4 := "4"     elsif P4 = 5 then         Player4 := "5"     elsif P4 = 6 then         Player4 := "6"     elsif P4 = 7 then         Player4 := "7"     elsif P4 = 8 then         Player4 := "8"     elsif P4 = 9 then         Player4 := "9"     elsif P4 = 10 then         Player4 := "10"         P4Win := true     end if     Font.Draw (Player1, 110, maxy - 160, font3, P1Color)     Font.Draw (Player2, maxx - 160, maxy - 160, font3, P2Color)     Font.Draw (Player3, maxx - 160, 110, font3, P3Color)     Font.Draw (Player4, 110, 110, font3, P4Color)     Font.Draw ("Player 1", 20, maxy - 40, font, P1Color)     Draw.Line (40, maxy - 60, 40, maxy - 180, P1Color)     Draw.Line (40, maxy - 180, 20, maxy - 150, P1Color)     Draw.Line (40, maxy - 180, 60, maxy - 150, P1Color)     Font.Draw ("Player 2", maxx - 180, maxy - 40, font, P2Color)     Draw.Line (maxx - 20, maxy - 80, maxx - 180, maxy - 80, P2Color)     Draw.Line (maxx - 180, maxy - 80, maxx - 150, maxy - 60, P2Color)     Draw.Line (maxx - 180, maxy - 80, maxx - 150, maxy - 100, P2Color)     Font.Draw ("Player 3", maxx - 180, 30, font, P3Color)     Draw.Line (maxx - 40, 60, maxx - 40, 180, P3Color)     Draw.Line (maxx - 40, 180, maxx - 20, 150, P3Color)     Draw.Line (maxx - 40, 180, maxx - 60, 150, P3Color)     Font.Draw ("Player 4", 20, 30, font, P4Color)     Draw.Line (20, 80, 180, 80, P4Color)     Draw.Line (180, 80, 150, 60, P4Color)     Draw.Line (180, 80, 150, 100, P4Color) end drawField procedure drawPaddel1     Input.KeyDown (key)     if key ('w') then         y2 += 1     elsif key ('s') then         y2 -= 1     end if     if y2 < 200 then         y2 := 200     elsif y2 + 75 > maxy - 200 then         y2 := maxy - 275     end if     drawfillbox (0, y2, 15, y2 + 75, P1Color) end drawPaddel1 procedure drawPaddel2     Input.KeyDown (key)     if key (KEY_RIGHT_ARROW) then         x1 += 1     elsif key (KEY_LEFT_ARROW) then         x1 -= 1     end if     if x1 < 200 then         x1 := 200     elsif x1 + 75 > maxy - 200 then         x1 := maxy - 275     end if     drawfillbox (x1, maxy, x1 + 75, maxy - 15, P2Color) end drawPaddel2 procedure drawPaddel3     Input.KeyDown (key)     if key ('8') then         y1 += 1     elsif key ('2') then         y1 -= 1     end if     if y1 < 200 then         y1 := 200     elsif y1 + 75 > maxy - 200 then         y1 := maxy - 275     end if     drawfillbox (maxx - 15, y1, maxx, y1 + 75, P3Color) end drawPaddel3 procedure drawPaddel4     Input.KeyDown (key)     if key ('l') then         x2 += 1     elsif key ('k') then         x2 -= 1     end if     if x2 < 200 then         x2 := 200     elsif x2 + 75 > maxy - 200 then         x2 := maxy - 275     end if     drawfillbox (x2, 0, x2 + 75, 15, P4Color) end drawPaddel4 procedure beginning     color (blue)     loop         Input.KeyDown (key)         Mouse.Where (mx, my, button)         Font.Draw ("PONG!", maxx div 2 - 75, maxy div 2 + 50, font, 13)         locate (23, 20)         put "What speed would you like to play at? (0,1,2,3)"         locate (24, maxcol div 2)                         %% Player 1 %%         locate (30, 15)         put "Player 1"..         Draw.FillBox (200, 222, 210, 232, 12)         Draw.FillBox (230, 222, 240, 232, 13)         Draw.FillBox (260, 222, 270, 232, 14)         Draw.FillBox (290, 222, 300, 232, 11)         %% Player 2 %%         locate (32, 15)         put "Player 2"..         Draw.FillBox (200, 190, 210, 200, 12)         Draw.FillBox (230, 190, 240, 200, 13)         Draw.FillBox (260, 190, 270, 200, 14)         Draw.FillBox (290, 190, 300, 200, 11)         %% Player 3 %%         locate (34, 15)         put "Player 3"..         Draw.FillBox (200, 158, 210, 168, 12)         Draw.FillBox (230, 158, 240, 168, 13)         Draw.FillBox (260, 158, 270, 168, 14)         Draw.FillBox (290, 158, 300, 168, 11)         %% Player 4 %%         locate (36, 15)         put "Player 4"..         Draw.FillBox (200, 126, 210, 136, 12)         Draw.FillBox (230, 126, 240, 136, 13)         Draw.FillBox (260, 126, 270, 136, 14)         Draw.FillBox (290, 126, 300, 136, 11)         if mx > 200 and mx < 210 and my > 222 and my < 232 and button = 1 then             P1Color := 12         elsif  mx > 230 and mx < 240 and my > 222 and my < 232 and button = 1 then             P1Color := 13         elsif  mx > 260 and mx < 270 and my > 222 and my < 232 and button = 1 then             P1Color := 14         elsif  mx > 290 and mx < 300 and my > 222 and my < 232 and button = 1 then             P1Color := 11         end if                 if mx > 200 and mx < 210 and my > 190 and my < 200 and button = 1 then             P2Color := 12         elsif  mx > 230 and mx < 240 and my > 190 and my < 200 and button = 1 then             P2Color := 13         elsif  mx > 260 and mx < 270 and my > 190 and my < 200 and button = 1 then             P2Color := 14         elsif  mx > 290 and mx < 300 and my > 190 and my < 200 and button = 1 then             P2Color := 11         end if                 if mx > 200 and mx < 210 and my > 158 and my < 168 and button = 1 then             P3Color := 12         elsif  mx > 230 and mx < 240 and my > 158 and my < 168 and button = 1 then             P3Color := 13         elsif  mx > 260 and mx < 270 and my > 158 and my < 168 and button = 1 then             P3Color := 14         elsif  mx > 290 and mx < 300 and my > 158 and my < 168 and button = 1 then             P3Color := 11         end if                 if mx > 200 and mx < 210 and my > 126 and my < 136 and button = 1 then             P4Color := 12         elsif  mx > 230 and mx < 240 and my > 126 and my < 136 and button = 1 then             P4Color := 13         elsif  mx > 260 and mx < 270 and my > 126 and my < 136 and button = 1 then             P4Color := 14         elsif  mx > 290 and mx < 300 and my > 126 and my < 136 and button = 1 then             P4Color := 11         end if         Draw.Box (320, 222, 330, 232, 7)         Draw.FillBox (321, 223, 329, 231, P1Color)         Draw.Box (320, 190, 330, 200, 7)         Draw.FillBox (321, 191, 329, 199, P2Color)         Draw.Box (320, 158, 330, 168, 7)         Draw.FillBox (321, 159, 329, 167, P3Color)         Draw.Box (320, 126, 330, 136, 7)         Draw.FillBox (321, 127, 329, 135, P4Color)         locate (38, 15)         put "Speed      0   1   2   3   "..         if mx < 210 and mx > 200 and my > 95 and my < 105 and button = 1 then             speed := 0             put speed         elsif mx > 230 and mx < 240 and my > 95 and my < 105 and button = 1 then             speed := 1             put speed         elsif mx > 260 and mx < 272 and my > 95 and my < 105 and button = 1 then             speed := 2             put speed         elsif mx > 295 and mx < 305 and my > 95 and my < 105 and button = 1 then             speed := 3             put speed         end if                 Draw.Box (200, 30, 320, 70, 7)         locate (41,31)         put "PLAY" ..         if mx > 200 and mx < 320 and my > 30 and my < 70 and button = 1 then             Play := true         end if         exit when Play = true and speed = 0 or Play = true and speed = 1 or Play = true and speed = 2 or Play = true and speed = 3            View.Update         end loop     end beginning beginning loop     drawField     drawPaddel1     drawPaddel2     drawPaddel3     drawPaddel4     % Reflection     if x + xd < 200 and y + yd > maxy - 200 or x + xd > maxx - 200 and y + yd > maxy - 200 or x + xd < 200 and y + yd < 200 or x + xd > maxx - 200 and y + yd < 200 or x + xd > maxx - 15 and y + yd < y1 + 75 and y + yd > y1 or x + xd < 15 and y + yd > y2 and y + yd < y2 + 75             then         xd *= -1     end if     if x + xd > maxx - 200 and y + yd > maxy - 200 or x + xd > maxx - 200 and y + yd < 200 or x + xd < 200 and y + yd > maxy - 200 or x + xd < 200 and y + yd < 200 then         %if x + xd > maxx - 25 and x + xd < maxx and y + yd < y1 + 150 and y + yd > y1 or x + xd < 25 and x + xd > 0 and y + yd < y2 + 150 and y + yd > y2 then         xd *= -1     end if     x += xd     if y + yd > maxy - 200 and x + xd > maxx - 200 or y + yd < 200 and x + xd > maxx - 200 or y + yd > maxy - 200 and x + xd < 200 or y + yd < 200 and x + xd < 200 or y + yd > maxy - 15 and x + xd > x1 and x + xd < x1 + 75 or y + yd < 15 and x + xd > x2 and x + xd < x2 + 75             then         yd *= -1     end if     if y + yd > maxy - 200 and x + xd < 200 or y + yd > maxy - 200 and x + xd > maxx - 200 or y + yd < 200 and x + xd > maxx - 200 or y + yd < 200 and x + xd < 200 then         yd *= -1     end if     y += yd     if x + xd < 15 and y + yd > y2 and y + yd < y2 + 75 then         hit := 1     elsif y + yd > maxy - 15 and x + xd > x1 and x + xd < x1 + 75 then         hit := 2     elsif x + xd > maxx - 15 and y + yd < y1 + 75 and y + yd > y1 then         hit := 3     elsif y +  yd < 15 and x + xd > x2 and x + xd < x2 + 75 then         hit := 4     end if     % Tells if the ball has left the screen and starts it up again.     if x + xd < -10 then         if hit = 1 then             P2 += 1             P3 += 1             P4 += 1         elsif hit = 2 then             P2 += 1         elsif hit = 3 then             P3 += 1         elsif hit = 4 then             P4 += 1         end if         hit := 0         x := 50         xd := 1         yd := 1         randint (y, 200, maxy - 200)         delay (1000)     elsif x + xd > maxx + 10 then     if hit = 1 then             P1 += 1         elsif hit = 2 then             P2 += 1         elsif hit = 3 then             P1 += 1             P2 += 1             P4 += 1         elsif hit = 4 then             P4 += 1         end if         hit := 0         x := maxx - 50         xd := -1         yd := -1         randint (y, 200, maxy - 200)         delay (1000)     end if     if y + yd < -10 then         if hit = 1 then             P1 += 1         elsif hit = 2 then             P2 += 1         elsif hit = 3 then             P3 += 1         elsif hit = 4 then             P1 += 1             P2 += 1             P3 += 1         end if         hit := 0         y := 50         xd := 1         yd := 1         randint (x, 200, maxx - 200)         delay (1000)     elsif y + yd > maxy + 10 then         if hit = 1 then             P1 += 1                    elsif hit = 2 then             P1 += 1             P3 += 1             P4 += 1         elsif hit = 3 then             P3 += 1         elsif hit = 4 then             P4 += 1         end if         hit := 0         y := maxy - 50         xd := -1         yd := -1         randint (y, 200, maxx - 200)         delay (1000)     end if     drawfilloval (x, y, 5, 5, 7)     if P1 = 10 then         P1Win := true     elsif P2 = 10 then         P2Win := true     elsif P3 = 10 then         P3Win := true     elsif P4 = 10 then         P4Win := true     end if     View.Update     delay (speed)     cls     exit when P1 = 10 or P2 = 10 or P3 = 10 or P4 = 10 end loop Draw.FillBox (0, 0, maxx, maxy, blue) if P1Win = true then     Font.Draw ("PLAYER 1 WINS!!", 150, 500, font, 0) elsif P2Win = true then     Font.Draw ("PLAYER 2 WINS!!", 150, 500, font, 0) elsif P3Win = true then     Font.Draw ("PLAYER 3 WINS!!", 150, 500, font, 0) elsif P4Win = true then     Font.Draw ("PLAYER 4 WINS!!", 150, 500, font, 0) end if Font.Draw ("Play Again? (Press F1)", 200, 250, font2, 0)

Yeah, i didn't post my source code earlier because it was really buggy. It's not a loop problem (bad choice of words on my part...) It's just that it will hit the same spots over and over again, until a paddle misses and starts it again at a random spot.. It's really hard to explain, so just try it out. And there's another glitch that I can't seem to find out: when it scores on player 2, the ball starts too low...

[Travveh]

I know /why/ it does it, and all that, it's just a matter of figuring out a way to fix it. >.<

And when I said the ball starts too low when scored on Player 2, that only happens occasionally.

Thanks again for any help.

[Travveh]

Oh, nevermind the Player 2 glitch thingy... On line 440, (randint (y,200,maxy-200)), the y and maxy need to be x's.

[Travveh]

Well, you guys were helpful. XP

[Delos]

Don't whine. We don't get paid to help you - we do this of our own volition in our own time.

code:

if x + xd < 200 and y + yd > maxy - 200 or x + xd > maxx - 200 and y + yd > maxy - 200 or x + xd < 200 and y + yd < 200 or x + xd > maxx - 200 and y + yd < 200 or x + xd > maxx - 15 and y + yd < y1 + 75 and y + yd > y1 or x + xd < 15 and y + yd > y2 and y + yd < y2 + 75             then         xd *= -1     end if

I have a feeling your error lies somewhere in this mass of conditions. I notice 2 things here: first, there are several distinct if clauses accomplishing essentially the same thing (2 affect x, 2 affect y). Since they are distinct, all 4 will be checked, which could potentially lead to a problem. For instance, if the conditions are met in clause 1, then xd will invert. However, once that is done, another round of conditions are checked...if these too are met, xd will invert again! Now, given that it has just inverted twice, it's back where it started, and chances are it's going to stay right there ad infinitum.
How to fix this?
This brings me to my second point.
If you look at the above code snippet, you'll notice that there are several parts of the if clause that are repeated. So, instead of having one really long run-on condition, why not nest a few if's and make your debugging life easier?
For instance:

code:

% instead of: if x > 10 and y <10 or x > 10 and y > 40 or x < 40 and y < 10 or x < 40 and y > 40 then %... % do: if x > 10 then   if y < 10 then     %...   elsif y > 40 then     %... elsif x < 40 then    if y < 10 then      %...    elsif y > 40 then      %...

There are a few more improvements you could add to that, but breaking things up like that makes your life a lot easier, and get's you to the same place.

Now as a general comment - learn to use parameters in your procedures, they will make your life a *lot* easier. Check out the [Turing Walkthrough] for links the relevant tuts.