Creating multiple instances of a class (fish) following different instances of a ball class

Programming Questions

estoldt

Creating multiple instances of a class (fish) following different instances of a ball class

in Programming Questions • 1 year ago

okay so yeah. I've been picking code and hacking things together, but I've got this app that is under construction.

I've gotten one instance of this fish class to follow one instance of the ball class, but was curious as to how I could populate more fish following more balls.

i.e, fish 1 following ball 1, fish 2 following ball 2, etc.

Then again, I'm probably going about this in a really bulky way, and there's probably a better way to get the same behavior, but for now, I'd just like some help trying to get this to work.

so the code is as follows.

Fish fish1;
Ball ball;
Rain rain;
float ballx,bally; // location
float[] xpos = new float[15];
float[] ypos = new float[15];
int[] rainXpos = new int[90];
int[] rainYpos = new int[90];
float circlex=150;
float circley=150;
//------------------SETUP-------------------
void setup(){
size(1024,768);
background(136,216,247);
smooth();
//Call Families
rain = new Rain();
ball = new Ball(1);
fish1 = new Fish();
//Setup Rain
for (int c = 0; c < rainXpos.length; c++)
{
rainXpos[c] = 0;
rainYpos[c] = 0;
}
//Fish
for (int i = 0; i < xpos.length; i++)
{
xpos[i]= 0 ;
ypos[i]= 0 ;
}
}
//-------------------DRAW--------------------
void draw(){
background (168,225,247);
rain.draw();
fish1.display(width/2, height/2);
ball.move();
ball.display();
}

Ball class:

class Ball {
float r; // radius
float speedx,speedy; // speed
// Constructor
Ball(float tempR) {
r = tempR;
ballx = random(width);
bally = random(height);
speedx = random( - 5,5);
speedy = random( - 5,5);
}
void move() {
ballx += speedx; // Increment x
bally += speedy; // Increment y
// Check horizontal edges
if (ballx > width || ballx < 0) {
speedx *= - 1;
}
//Check vertical edges
if (bally > height || bally < 0) {
speedy *= - 1;
}
}
// Draw the ball
void display() {
fill(136,216,247);
ellipse(ballx,bally,r*2,r*2);
}
}

Fish Class:

class Fish {
float xspeed;
float yspeed;
float mov = 0;
float mi = 0.1;
void display(int x, int y){
//Lilypad Following
if (mousePressed == true) {
mov = mov + mi ;
if (mov > .4 || mov < -.4) {mi = mi * -1; }
xspeed = (((mouseX-circlex))/120);
yspeed = (((mouseY-circley))/120);
circlex += xspeed + mov/2;
circley += yspeed + mov;
if (circlex > width) {circlex=width;}
if (circley >height) {circley=height;}
for (int i = 1; i<xpos.length-1; i++){
xpos[i] = xpos[i+1];
ypos[i] = ypos[i+1];
}
}
//end mousepressed
//Maxe this follow ballx, bally
else {
mov = mov + mi ;
if (mov > .4 || mov < -.4) {mi = mi * -1; }
xspeed = (((ballx-circlex))/150);
yspeed = (((bally-circley))/150);
circlex += xspeed + mov/2;
circley += yspeed + mov;
if (circlex > width) {circlex=width;}
if (circley >height) {circley=height;}
for (int i = 1; i<xpos.length-1; i++){
xpos[i] = xpos[i+1];
ypos[i] = ypos[i+1];
}
}
xpos[xpos.length-1] = circlex;
ypos[ypos.length-1] = circley;
for (int i =0;i < xpos.length; i++)
{
noStroke();
fill(2,51,59);
ellipse(xpos[i],ypos[i],((xpos.length)/3.5)-i,((xpos.length)/2)-i);
}
}
}

Rain Class:

class Rain {
void draw()
{
fill(0);
rainXpos[rainXpos.length-1] = int(random(1,width));
rainYpos[rainYpos.length-1] = int(random(1,height));
for (int c =0; c < rainXpos.length -1 ; c++)
{
rainXpos[c]=rainXpos[c+1];
rainYpos[c]=rainYpos[c+1];
}
for (int c =0; c< rainXpos.length; c++)
{
stroke(255,255,255,c);
noFill();
ellipse(rainXpos[c],rainYpos[c],90-c,90-c);
}
}
}

Replies(1)

PhiLho

Re: Creating multiple instances of a class (fish) following different instances of a ball class

1 year ago

One think strikes me: your classes use global variables for their specific behavior. Sometime it is OK, but here, ballx and bally belong obviously to Ball (and there, can be renamed just x and y), rainXpos and rainYpos belong to Rain (and again, name can be simplified), and so on.

I understand that you needed ballx in the Fish class, but that's precisely the problematic point of your sketch: it doesn't scale to more items.
One way to do what you want would look like:
ball1 = new Ball(10);
ball2 = new Ball(5); // Or use array if you plan to have many balls
fish1 = new Fish(ball1);
fish2 = new Fish(ball1);
fish3 = new Fish(ball2); // Idem, arrays might be better
The first two fishes will follow ball1, the last one will follow ball2.
Of course, you have to modify the constructor of Fish to take a Ball parameter. Store the ball reference in a field of Fish, and use the x, y coordinates of the ball to do the follow movements.

Top Reply