Hi all, i am new to allegro, just started around 3 or 4 days ago, i went through tutorials that i could find and learned sum stuff and looked at their code for pong and other games and decided to try and make my own pong clone useing what i had learned, so i set about it and got so far as to make 2 paddles and a ball. Both paddles move fine but i cannot figure out how to make them reflect the ball. i also cannot figure out how to stop the paddles from going off the map or make the ball reflect off the top and bottom walls, can anyone tell me how to set up boundaries for the walls and the paddle to reflect the ball?

cool thx i will try that and post back results
Danex!

1)
ok, i get that part about the paddle logic, i set the paddles to not go below 0 or above 480 with
if (paddle_1_y < 0){
paddle_1_y = 0;}
if (paddle_2_y < 0){
paddle_2_y = 0;}
if (paddle_1_y > 480){
paddle_1_y = 480;}
if (paddle_2_y > 480){
paddle_2_y = 480;}
part of it works becuase the paddle will not go below 0, but the paddle goes alittle below my screen where i can see part but part is off the screen, i think it may be a problem with my screen becuase the paddle diffinently stops and won't move any more
2) i cannot get the ball to move right???, thats my move ball function below, it also has my logic for bounceing the ball off the paddle

void move_ball(){

if (ball_x == 630) {
if (ball_y > paddle_2_y, paddle_2_y + 79 > ball_y)
{ ball_x--; }
else if(ball_x==635) {
ball_x--;
textout_ex( buffer, font, "Player 1 Wins!", 320, 240, makecol( 255, 0, 0), makecol( 0, 0, 0)); }
}

if (ball_x == 5){
if (ball_y > paddle_2_y, paddle_2_y + 79 > ball_y)
{ ball_x--; }
else if (ball_x==0){
ball_x++;
textout_ex( buffer, font, "Player 2 Wins!", 320, 240, makecol( 255, 0, 0), makecol( 0, 0, 0));
} }
circlefill( buffer, ball_x, ball_y , 5, makecol( 0,255, 0));
}

ok so first off i need to change --->
if (paddle_1_y < 0){
paddle_1_y = 0;}
if (paddle_2_y < 0){
paddle_2_y = 0;}
if (paddle_1_y > 480){
paddle_1_y = 480;}
if (paddle_2_y > 480){
paddle_2_y = 480;}
to something like --->
if (paddle_1_y + paddle_1_hight > 480){
paddle_1_y = 480;}

and second i need to scrap the whole move ball function and restart with 4 variables of x,y,x_speed,y_speed
in the second part i do not understand why that makes the ball move, am i supposed to update x_speed to update x?
Danex!
P.S. thx for all ur help and understanding that i am ignorant of allegro logic

mk i set up the boundaries for the paddle like you said and if worked perfectly
thanks alot, can you give kudos or karma or something on this forum?
also is it a good idea to mix primitives like
"circlefill( buffer, ball_x, ball_y , 5, makecol( 0,255, 0));"
with bitmaps, or should i just make another bitmap of a ball?
P.S. working on the moving ball and i am currently using a primative for the ball and don't want that to mess my program

OK made a new move_ball()
void move_ball(){
int x_speed=1;
int y_speed=1;
ball_x += x_speed;
ball_y += y_speed;

if (ball_y < 0){
ball_y = 0;}
if (ball_y > 475){
ball_y = 475;}
if (ball_x == 5 && ball_y >= paddle_1_y && ball_y <= paddle_1_y){
x_speed = -1;
y_speed = -1; }
if (ball_x == 635 && ball_y >= paddle_2_y && ball_y <= paddle_2_y){
x_speed = -1;
y_speed = -1; }
i am gettin somewhere at least cause the ball moves down and to the right
and i tried the greator than or equal to math but i am gettin no reflection
On, the plus side i applied the same logic used in the paddles to make the ball not able to leave the map
However, the ball merely sticks to the bottom and straight lines to the end
i believe this is due to me not makeing the ball bounce with this --->
if (ball_y < 0){
ball_y = 0;}
if (ball_y > 475){
ball_y = 475;}

what should i add so that

if (ball_y < 0){
ball_y = 0;
---->switch direction of incoming ball(bounce)}
if (ball_y > 475){
ball_y = 475;
---->switch direction of incoming ball(bounce)}

OMFG!!!!111

Stop the madness!! CGames is telling a newb to use globals!!! He's out of control, someone stop him!!!!

Danex!, when you use global variables, it makes kittens cry.

In Soviet Russia, global variables use you!

In order for the ball to bounce off the top of the screen, you need to see when the ball's y is less than 0
if(ball_y < 0)
And if it is, then make it move down instead.
y_speed = 1;

Do the opposite for downward movement.

[edit]
Fixed.

It shouldn't randomly bounce mid-screen if your code is what you have up there in addition to what I said.

About the ball going through paddles: you compare that the ball's y is >= the paddle's y, and that the ball's y is <= the paddle's y. This means you have to hit the very top of the paddle in order to bounce.

You should be checking that the ball's y is >= the paddle's y, and the ball's y is <= the paddle's y + height. That is, the ball needs to be in between the top of the paddle and the bottom of it.