Array List draws behind Objects
in
Programming Questions
•
1 year ago
Hello there, i feel like a blockhead with this question.
The following code is the copy of the
Array List example,
added with some lines to give a random color to each ellipse. It works fine, but i want to draw every new ellipse
in front of the last one rather than
behind.
- ArrayList balls;
- int ballWidth = 48;
- void setup() {
- size(200, 200);
- smooth();
- noStroke();
- // Create an empty ArrayList
- balls = new ArrayList();
- // Start by adding one element
- balls.add(new Ball(width/2, 0, ballWidth));
- }
- void draw() {
- background(255);
- // With an array, we say balls.length, with an ArrayList, we say balls.size()
- // The length of an ArrayList is dynamic
- // Notice how we are looping through the ArrayList backwards
- // This is because we are deleting elements from the list
- for (int i = balls.size()-1; i >= 0; i--) {
- // An ArrayList doesn't know what it is storing so we have to cast the object coming out
- Ball ball = (Ball) balls.get(i);
- ball.move();
- ball.display();
- if (ball.finished()) {
- // Items can be deleted with remove()
- balls.remove(i);
- }
- }
- }
- void mouseDragged() {
- // A new ball object is added to the ArrayList (by default to the end)
- balls.add(new Ball(mouseX, mouseY, ballWidth));
- }
- // Simple bouncing ball class
- class Ball {
- float x;
- float y;
- float speed;
- float gravity;
- float w;
- float life = 255;
- PVector col;
- Ball(float tempX, float tempY, float tempW) {
- x = tempX;
- y = tempY;
- w = tempW;
- speed = 0;
- gravity = 0.1;
- col = new PVector(random(255),random(255),random(255));
- }
- void move() {
- // Add gravity to speed
- speed = speed + gravity;
- // Add speed to y location
- y = y + speed;
- // If square reaches the bottom
- // Reverse speed
- if (y > height) {
- // Dampening
- speed = speed * -0.8;
- y = height;
- }
- }
- boolean finished() {
- // Balls fade out
- life--;
- if (life < 0) {
- return true;
- } else {
- return false;
- }
- }
- void display() {
- // Display the circle
- fill(col.x,col.y,col.z,life);
- //stroke(0,life);
- ellipse(x,y,w,w);
- }
- }
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