hello!

I'm very new to Processing and even to programming at all.
I was wondering how in the collision example the white ball can be replaced by a picture that is (100 x 73)?

It would be wonderful if someone could help me with this!

Thank you,
Luc

hello and thanks for your quick answer.
It's the example in Processing itself, choose: file/examples/topics/motion and there it is.

I tried this and in the section "draw ball" I put:

PImage ball;
ball = loadImage("myimage.jpg");
image(ball, ball_x, ball_y);

But this doesn't work (I get a NullPointerException) although my picture is in the correct file.

I thought hat maybe it is because of the size. Therefore I changed ball_size into 100 or 73 (my picture is 100x73). I also deleted "float ball_size = 15;  // Radius"

This is what I have now (as a slight variation of the Processing example):

/**
* Collision (Pong).
*
* Move the mouse up and down to move the paddle.  
*/

// Global variables for the ball
float ball_x;
float ball_y;
float ball_dir = 1;
float dy = 0;  // Direction

// Global variables for the paddle
int paddle_width = 10;
int paddle_height = 60;

int dist_wall = 15;

void setup()
{
 size(640, 360);;
 noStroke();
 smooth();
 ball_y = height/2;
 ball_x = 1;
}

void draw()
{
 background(51);
 
 ball_x += ball_dir * 1.0;
 ball_y += dy;
 if(ball_x > width + 100) {
   ball_x = -width/2 - 100;
   ball_y = random(0, height);
   dy = 0;
 }
 
 // Constrain paddle to screen
 float paddle_y = constrain(mouseY, paddle_height, height-paddle_height);

 // Test to see if the ball is touching the paddle
 float py = width-dist_wall-paddle_width-73;
 if(ball_x == py
    && ball_y > paddle_y - paddle_height - 73
    && ball_y < paddle_y + paddle_height + 73) {
   ball_dir *= -1;
   if(mouseY != pmouseY) {
     dy = (mouseY-pmouseY)/2.0;
     if(dy >  5) { dy =  5; }
     if(dy < -5) { dy = -5; }
   }
 }
 
 // If ball hits paddle or back wall, reverse direction
 if(ball_x < 100 && ball_dir == -1) {
   ball_dir *= -1;
 }
 
 // If the ball is touching top or bottom edge, reverse direction
 if(ball_y > height-73) {
   dy = dy * -1;
 }
 if(ball_y < 73) {
   dy = dy * -1;
 }

 // Draw ball
 PImage ball;
 ball = loadImage("flyingcarpet");
 image(ball, ball_x, ball_y);
 
 // Draw the paddle
 fill(153);
 rect(width-dist_wall, paddle_y, paddle_width, paddle_height);  
}

Thanks for helping me out!

Luc

Hello and thank you for your reply.
Using my image worked very well now thanks to your advice! Now I have to make sure that the collision with the bar works fine...

Greetings
luc