maybe it is because you have

1. background (0,0) ;

in draw()?

Cheers, Chrisir

           

The background (0,0) is the layer on top of my background which has a light blue color (225,225, 255).

It's 0,0 because the layer library indicates that layers must be this value.

In any case, the image does appear but then it disappears in relation to mouse or key events...

Sorry, I don't know the library layer.

you could also store the copies with positions in an ArrayList and draw all its Elements in draw().

Chrisir

It could look like this - this is reacting on MousePressed

1. // from http://processing.org/learning/topics/arraylistclass.html
2. ArrayList balls;
3. int ballWidth = 48;
4. // =====================================================================
5. void setup() {
6.   size(200, 200);
7.   smooth();
8.   noStroke();
9.   // Create an empty ArrayList
10.   balls = new ArrayList();
11.   // Start by adding one element
12.   balls.add(new Ball(width/2, 0, ballWidth));
13. }
14. void draw() {
15.   background(255);
16.   // With an array, we say balls.length, with an ArrayList, we say balls.size()
17.   // The length of an ArrayList is dynamic
18.   // Notice how we are looping through the ArrayList backwards
19.   // This is because we are deleting elements from the list 
20.   for (int i = balls.size()-1; i >= 0; i--) {
21.     // An ArrayList doesn't know what it is storing so we have to cast the object coming out
22.     Ball ball = (Ball) balls.get(i);
23.     ball.move();
24.     ball.display();
25.     if (ball.finished()) {
26.       // Items can be deleted with remove()
27.       balls.remove(i);
28.     }
29.   }
30. }
31. // =====================================================================
32. void mousePressed() {
33.   // A new ball object is added to the ArrayList (by default to the end)
34.   balls.add(new Ball(mouseX, mouseY, ballWidth));
35. }
36. // =====================================================================
37. // Simple bouncing ball class
38. class Ball {
39.   float x;
40.   float y;
41.   float speed;
42.   float gravity;
43.   float w;
44.   float life = 255;
45.   Ball(float tempX, float tempY, float tempW) {
46.     x = tempX;
47.     y = tempY;
48.     w = tempW;
49.     speed = 0;
50.     gravity = 0.1;
51.   }
52.   void move() {
53.     // Add gravity to speed
54.     speed = speed + gravity;
55.     // Add speed to y location
56.     y = y + speed;
57.     // If square reaches the bottom
58.     // Reverse speed
59.     if (y > height) {
60.       // Dampening
61.       speed = speed * -0.8;
62.       y = height;
63.     }
64.   }
65.   boolean finished() {
66.     // Balls fade out
67.     // life--;
68.     if (life < 0) {
69.       return true;
70.     }
71.     else {
72.       return false;
73.     }
74.   }
75.   void display() {
76.     // Display the circle
77.     fill(0, life);
78.     //stroke(0,life);
79.     ellipse(x, y, w, w);
80.   }
81. } 
82. // =====================================================================
83. // Processing was initiated by Ben Fry and Casey Reas

Concerning overview:

Yeah, I use different tabs. That makes me feel like having the overview.

For instance I have one tab "classes" or one tab "Inputs" (for keyPressed and Mouse stuff).

You can add tabs with the "+" to the right.

Also try to keep setup and draw and other functions rather short. Try to make functions and sub-functions to divide your Code in handy packages. Give them good names telling what they do.

Maybe that helps.


ArrayList is fairly simple. You have a list of Balls and just push more Balls in it; this happens in mousePressed():

1.   balls.add(new Ball(mouseX, mouseY, ballWidth));

Then you just loop through the list and paint all the balls that are currently in there - in draw():

1. for (int i = balls.size()-1; i >= 0; i--) {
2.     // An ArrayList doesn't know what it is storing so we have to cast the object coming out
3.     Ball ball = (Ball) balls.get(i);
4.     ball.move();
5.     ball.display();
6.   }

For your problem:

In fact, it will even stick until I click or press a key. 

Maybe you just overwrite your old variable and then only the new one is drawn.

Anyway - when you don't have any background in draw() but only in setup() that should help.


Kick some butt!

Chrisir    

if you like, post me your code and the pictures
<deleted> and i'll see what i can do  

What is a sub-function, please? (You wrote that word in your message).

with the word "sub-function" I just wanted to suggest to have a function that's called by another function

but looking at your Code I see it is already good Code with different classes, so I have to apologize to making such trivial suggestions...