Computer Science Canada

PONG HELP - Need help bouncing ball off paddle?
Author:  ashvinthecha [ Thu Jun 04, 2009 4:38 pm ]
Post subject:  PONG HELP - Need help bouncing ball off paddle?
I dont know how to say if ballx hits the paddle then the dirRight causes the ball to bounce the other way


setscreen ("offscreenonly")
var x : int
var y : int
var p1 : string
var p2 : string
var ashvin := 100
var ashvin2 := 180
var ashvin3 := 100
var ashvin4 := 180
var ballx := maxx div 2
var bally := maxy div 2
var background := white
var getKey : array char of boolean

procedure Screen
drawfillbox (0, 0, maxx, maxy, background)
drawfillbox (20, ashvin, 30, ashvin2, black)
drawfillbox (maxx - 20, ashvin3, maxx - 30, ashvin4, black)
end Screen

procedure MoveP1Up
drawfillbox (20, ashvin2, 30, ashvin, background)
ashvin += 2
ashvin2 += 2
drawfillbox (20, ashvin2, 30, ashvin, black)
delay (3)
end MoveP1Up
procedure MoveP1Down
drawfillbox (20, ashvin2, 30, ashvin, background)
ashvin -= 2
ashvin2 -= 2
drawfillbox (20, ashvin2, 30, ashvin, black)
delay (3)
end MoveP1Down
procedure MoveP2Up
drawfillbox (maxx - 20, ashvin3, maxx - 30, ashvin4, background)
ashvin3 += 2
ashvin4 += 2
drawfillbox (maxx - 20, ashvin3, maxx - 30, ashvin4, black)
delay (3)
end MoveP2Up
procedure MoveP2Down
drawfillbox (maxx - 20, ashvin3, maxx - 30, ashvin4, background)
ashvin3 -= 2
ashvin4 -= 2
drawfillbox (maxx - 20, ashvin3, maxx - 30, ashvin4, black)
delay (3)
end MoveP2Down
process balldir
var dirUp : boolean := true
var dirRight : boolean := true
loop
cls
if dirUp then
if bally >= 10 then
bally := bally - 5
else
dirUp := false
end if
else
if bally <= maxy then
bally := bally + 5
else
dirUp := true
end if
end if
if dirRight then
if ballx >= 10 then
ballx := ballx - 5
else
dirRight := false
end if
else
if ballx <= maxx then
ballx := ballx + 5
else
dirRight := true
end if
end if
Draw.FillOval (ballx, bally, 10, 10, black)
delay (50)
end loop
end balldir
process movePaddels
loop
% draw paddle on left
drawfillbox (20, ashvin, 30, ashvin2, black)
Input.KeyDown (getKey)
if getKey ('q') then
MoveP1Up
end if
if getKey ('a') then
MoveP1Down
end if
% if we are running off of the screen don't move off of the screen
if (ashvin <= 0) and (ashvin2 <= 80) then
ashvin := 0
ashvin2 := 80
elsif (ashvin >= maxy - 80) and (ashvin2 >= maxy - 80) then
ashvin2 := maxy
ashvin := maxy - 80
end if
% other paddel -- on right
drawfillbox (maxx - 20, ashvin3, maxx - 30, ashvin4, black)
Input.KeyDown (getKey)
if getKey (KEY_UP_ARROW) then
MoveP2Up
end if
if getKey (KEY_DOWN_ARROW) then
MoveP2Down
end if
if (ashvin3 <= 0) and (ashvin4 <= 80) then
ashvin3 := 0
ashvin4 := 80
elsif (ashvin3 >= maxy - 80) and (ashvin4 >= maxy - 80) then
ashvin4 := maxy
ashvin3 := maxy - 80
end if
View.Update
end loop
end movePaddels


% beginning of program
fork movePaddels
fork balldir
Author:  Tony [ Thu Jun 04, 2009 4:59 pm ]
Post subject:  RE:PONG HELP - Need help bouncing ball off paddle?
code:

if ball_x == paddle_x then
   ball_velocity_x *= -1
end if


Although unless the ball never travels faster than 1 pixel per frame, the exact match might not happen.
Author:  ashvinthecha [ Thu Jun 04, 2009 5:18 pm ]
Post subject:  RE:PONG HELP - Need help bouncing ball off paddle?
im sorry but that does not really help me out because i dont use ball velosity in my program and i dont have a thing for my paddle.

to be honest i dont understand turing to well and i cud just use some clarification
Author:  Tony [ Thu Jun 04, 2009 5:38 pm ]
Post subject:  RE:PONG HELP - Need help bouncing ball off paddle?
http://compsci.ca/blog/super-paper-programming/

- take out a piece of paper
- sketch out the layout of your pong game
- describe how you would know if the ball is hitting the paddle or not
Author:  ashvinthecha [ Thu Jun 04, 2009 6:15 pm ]
Post subject:  RE:PONG HELP - Need help bouncing ball off paddle?
alright i have attempted that method on several occasions and it's not like i havent attempted other variations. Im sorry but i still dont understand.
Author:  Kharybdis [ Thu Jun 04, 2009 8:22 pm ]
Post subject:  RE:PONG HELP - Need help bouncing ball off paddle?
try whatdotcolour collision detection. When the colour of the paddle has been detected, assign the x value and y values to be the negatives of each other.

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