My pong game...some things I need help with

[Pro Programmer!]

Okay I got the collision all down. Its old school pong. No extra touch added.

code:

var chars : array char of boolean var up1 : int := 50 var up2 : int := 50 var down1 : int := 1 var down2 : int := 1 var ballx, bally : int var speed, speed1 : int := 1 var size : int := 5 ballx := Rand.Int (10, 100) %sets the x of the ball bally := Rand.Int (10, 100) %sets the y of the ball loop     Input.KeyDown (chars)     if chars (KEY_UP_ARROW) then % makes pong bar 2 move up if up arrow pressed         up1 := up1 + 1         down1 := down1 + 1     end if     if chars (KEY_DOWN_ARROW) then % makes pong bar 2 move down if down arrow pressed         up1 := up1 - 1         down1 := down1 - 1     end if     if chars ('s') then % makes pong bar 1 move if 's' is pressed         up2 := up2 - 1         down2 := down2 - 1     end if     if chars ('w') then % makes pong bar 1 move is 'w' is pressed         up2 := up2 + 1         down2 := down2 + 1     end if      if bally <= 0 then % checks to see if ball goes off bottom of screen         speed := 1 % if it is this changes the direction     end if     if bally >= maxy then %checks to see if ball goes off top of screen         speed := - 1 % if it does this changes the direction     end if     colourback (black) % makes background black     drawfillbox (20, up2, 30, down2, white) % draws pong bar 1     drawfillbox (600, up1, 610, down1, white) % draw pong bar 2     delay (3)     cls     Draw.FillOval (ballx, bally, size, size, white) % draws ball     ballx += speed1 % this makes ball move     bally += speed     if ballx = 600 and bally < up1 and bally > down1 then %checks to see if ball hits pong bar 2     speed1 := -1 % if it does this changes the direction     elsif ballx = 20 and bally < up2 and bally > down2 then % checks to see if ball hits pong bar 1     speed1 := 1 % if it does this changes direction     end if     end loop

I have a few problems. My paddles can and will go off the screen. How do I make it so that it doesn't and can go only as far as maxx and 0. Now I want to start off my ball speed slower than I have it but after a certain amount of time I want it to get faster. I know how I would make it faster and all but how would I go about doing it after a certain amount of time...say every 15 seconds? Thats all my questions for now and thanx for the help!

[Pro Programmer!]

Forgot to add one more thing. My ball always starts off in the same place how do I make it so that it starts a bit more random? I haven't finished and I will make a menu and all and make scores and winners and everything. I just got the hard part finished first!

[Cervantes]

Welcome.

Glad to see you used [code ][/code ] tags. Although, they aren't that important if your code isn't indented properly.

• To prevent the paddle from going off the screen:
  

  code:

  if paddle.x > maxx then     paddle.x := maxx elsif paddle.x < 0 then     paddle.x := 0 end if

  
  Note that you will have to incorporate the width of the paddle into that.
  
  Alternatively, you could do something like this:
  

  code:

  paddle.x := max (0, paddle.x) paddle.x := min (paddle.x, maxx)

  
  Which can then be compressed to:
  

  code:

  paddle.x := min (max (0, paddle.x), maxx)

  
  
  
• Use Time.Elapsed to determine when 15 seconds has passed.
  

  code:

  var current_time := 0 loop     if Time.Elapsed - current_time > 15000 then         %speed up ball         current_time := Time.Elapsed     end if end loop

  
  
• To get a "random" integer, use the Rand.Int function.
  

[Pro Programmer!]

Thanx alot!

[Pro Programmer!]

Wow ok I did all that and everything and I realized something...I have NO idea how the AI is going to work. I'm going to want difficulty levels ofcourse.

[Cervantes]

The simplest AI for pong would be like this:

If the ball is above the paddle, move the paddle up
If the ball is below the paddle, move the paddle down

For levels, you can speed the paddle of the movement up, though beyond a certain point it becomes impossible to beat the computer.

A more advanced AI would be to try to predict where the ball will go (use some math), then move the paddle to that spot.

[Pro Programmer!]

Ok I have 1 more question now (sorry lol). I did the AI like you said ceraventes but now its impossible to beat. It ALWAYS gets to it. It never missed...heres my new code

code:

var chars : array char of boolean var up1 : int := 50 var up2 : int := 50 var down1 : int := 1 var down2 : int := 1 var ballx, bally : int var speed, speed1 : int := 1 var size : int := 5 var RunningTime := 0 var team1, team2 : int := 0 var player : string ballx := Rand.Int (10, 100) %sets the x of the ball bally := Rand.Int (10, 500) %sets the y of the ball put "1 player or 2 players? 1p for 1 player and 2p for 2 player" get player loop     put "Team 1 = ", team1, " points"     locate (1, 64)     put "Team 2 = ", team2, " points"     Draw.FillOval (ballx, bally, size, size, white)     drawfillbox (600, up1, 610, down1, white)     drawfillbox (20, up2, 30, down2, white)     Input.KeyDown (chars)     if player = "2p" then         if chars (KEY_UP_ARROW) then % makes pong bar 2 move up if up arrow pressed             up1 := up1 + 1             down1 := down1 + 1         elsif chars (KEY_DOWN_ARROW) then % makes pong bar 2 move down if down arrow pressed             up1 := up1 - 1             down1 := down1 - 1         end if     end if     if chars ('s') then     % makes pong bar 1 move if 's' is pressed         up2 := up2 - 1         down2 := down2 - 1     end if     if chars ('w') then     % makes pong bar 1 move is 'w' is pressed         up2 := up2 + 1         down2 := down2 + 1     end if     if bally <= 0 then     % checks to see if ball goes off bottom of screen         speed := 1     % if it is this changes the direction     end if     if bally >= maxy then     %checks to see if ball goes off top of screen         speed := -1     % if it does this changes the direction     end if     if player = "1p" then         if bally < up1 then             down1 := down1 - 1             up1 := up1 - 1         elsif bally > down1 then             down1 := down1 + 1             up1 := up1 + 1         end if     end if     if down1 <= 0 then     %This if statement prevents the paddles from going off the screen         down1 := 0         up1 := 49     elsif up1 >= maxy then         down1 := maxy - 49         up1 := maxy     end if     if down2 <= 0 then         down2 := 0         up2 := 49     elsif up2 >= maxy then         down2 := maxy - 49         up2 := maxy     end if     if ballx = 630 then     % This adds one point everytime the ball reaches a point and then resets the coordinates         cls             % of the paddle and the ball         colour (white)         put "Team 1 scores!"         team1 := team1 + 1         delay (2000)         up1 := 50         up2 := 50         down1 := 1         down2 := 1         ballx := Rand.Int (10, 100)         bally := Rand.Int (10, 500)     elsif ballx = 0 then         cls         colour (white)         put "Team 2 scores!"         team2 := team2 + 1         delay (2000)         up1 := 50         up2 := 50         down1 := 1         down2 := 1         ballx := Rand.Int (500, 600)         bally := Rand.Int (10, 500)     end if     if team1 = 5 then         cls         colour (white)         locate (23, 40)         put "Team 1 wins!"         delay (2000)         exit     elsif team2 = 5 then         cls         colour (white)         locate (23, 40)         put "Team 2 wins!"         delay (2000)         exit     end if     colourback (black)     % makes background black     ballx += speed1     % this makes ball move     bally += speed     if ballx = 600 and bally <= up1 and bally >= down1 then     %checks to see if ball hits pong bar 2         speed1 := -1     % if it does this changes the direction     elsif ballx = 30 and bally <= up2 and bally >= down2 then     % checks to see if ball hits pong bar 1         speed1 := 1     % if it does this changes direction     end if     delay (3)     cls end loop

[Cervantes]

Try to impliment a little bit of randomness or poor decision or hesitation into the AI.

Pick a random number (Rand.Int), from 1 to 100, say. If it is a 1, move the paddle the wrong way. Therefore, 1% of the time the computer will move the wrong way.

[Bored]

The problem with the formentioned aproach is that the ai can look sorta shaky if you want it to be bad enough to beat. A better approach might be to have the ai paddle move slightly slower then the ball. I'd suggest using a real value for the speed and position so that you can fine tune the speed more accuratly and if your using a ball speed of say 1 the paddle could then move at like .75 and thus be slower.

[Pro Programmer!]

Yea I tried that bored. That way however, the paddle misses the ball 80% of the time. I will do what you said ceraventes and thanks for the enormous amount of help! I will make it more than 1% though. Anyways when I finish I will post it on applications!