Assign value once to every object

Programming Questions

martijnbac

Assign value once to every object

in Programming Questions • 1 year ago

Hello,

I working on a simple program as a part of a sound-reactive installation. Every time the sound velocity is more than 5, a rectangle comes in on the right, and all other objects shift one place to the left.

The problem: the velocity is the width/height of the rectangles. Now it affects all objects, but I only want to assign the value to the newest, so all rectangles get their own size (and stay that size). Maybe there is something wrong with void show() and I tried things with an arraylist, but I'm afraid I'm a bit lost.

This is a simplified example to make it more clear, in the real version the rectangles are characters (kind of sound-reactive newsticker).

If anyone can point me in the right direction, that would be great :-)

full code:

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import ddf.minim.*;
Minim minim;
AudioInput in;
AudioRecorder recorder;
Rectangle[] myRectangle;
float[] vs = new float[1000];
float vel;
int count;
int index;
public float y;
private float v;
String txt;
void setup() {
size(1024, 400);
noStroke();
minim = new Minim(this);
in = minim.getLineIn(Minim.STEREO, 2048);
count = 50;
char[] allChars = new char[count];
myRectangle = new Rectangle[count];
for (int i = 0; i < count; i++) {
myRectangle[i] = new Rectangle();
}
}
void draw() {
y = in.left.get(2)*800;
scale(0.1);
background(255);
translate(0, 200);
if (y>5) {
show();
}
for (int i=0;i<count;i++) {
vel = y;
myRectangle[i].display();
}
}
void show() {
if (index<count) {
for (int i=0;i<index;i++) {
vel = y;
myRectangle[i].update();
}
}
index++;
}

class

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class Rectangle {
float xpos;
Rectangle() {
xpos = width*10;
}
void display() {
fill(0, 99, 220);
rectMode(CENTER);
rect(xpos+40, 0, vel, vel);
}
void update() {
int spacing = 300;
xpos = xpos - spacing;
}
}

Replies(8)

calsign

Re: Assign value once to every object

1 year ago

The problem is that you are using vel to display all of the rectangles. If you want the rectangles to be size-independent, then you need to make a size value for each of the rectangles (that is, inside the Rectangle class... probably assigned when the value is received and the rectangle is created).

martijnbac

Re: Assign value once to every object

1 year ago

Thanks for your fast response! I tried this:

in draw:

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for (int i=0;i<count;i++) {
vel[i] = y;
myRectangle[i].display(vel[i]);
}

in class:

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void display(float vel) {
fill(0, 99, 220);
rectMode(CENTER);
rect(xpos+40, 0, vel, vel);
}

This seems to work with a normal array, but the value y (microphone input) is constantly changing, so I probably need another way to add the received values to the array. Any ideas?

calsign

Re: Assign value once to every object

1 year ago

Can you just add a field to the Rectangle class that contains the size of the rectangle... and reference that?

martijnbac

Re: Assign value once to every object

1 year ago

That doesn't seem to work either. Or maybe I didn't understand it right, maybe you can try it and post an example? Thanks!

calsign

Re: Assign value once to every object

1 year ago

Quite frankly, I don't understand your code enough in order to generate an example...
Where in the code do you add a new rectangle?
Are the rectangles stored properly?

Basically, in order for each rectangle to retain its own size, it needs a locally store variable containing the size...
Similar to the xpos.

When the rectangle is created, that size is assigned to the current vel.

martijnbac

Re: Assign value once to every object

1 year ago

In setup() I create al rectangles ( myRectangle[i] = new Rectangle(10); ). I show them with display() in draw. And change the xpos in update();

But I can't assign the value in setup(), because there isn't sound yet in setup. That's why I wanted to assign the sound value with display().

Maybe I need to create the rectangles with an arraylist, so I can create them in the draw? I've tried this already, but maybe in a wrong way.

Oh, and this what I am trying to do: I simplified it to rectangles, but in the end it will be characters consisting of rectangles with a different size for every character (the code to import text and create the characters out of rectangles works already, but isn't relevant for this problem).

martijnbac

Re: Assign value once to every object

1 year ago

Woohoo, I finally figured it out. Thanks for al the help! I needed to store the rectangles in an arraylist; first time I used that, so it took me a while to find out how it works.

The process and end result (in a few weeks) can be seen on examen.martijnvanbachum.com (dutch), final project for my study graphic design.

Copy code

ArrayList <Rectangle> Rectangles = new ArrayList <Rectangle> ();
import ddf.minim.*;
Minim minim;
AudioInput in;
AudioRecorder recorder;
float v;
void setup() {
size(1024, 400);
noStroke();
minim = new Minim(this);
in = minim.getLineIn(Minim.STEREO, 2048);
}
void draw() {
background(#FFFFFF);
for (Rectangle lt : Rectangles) {
lt.display();
}
v = in.left.get(2)*2000;
println(v);
if (v>5) {
Rectangles.add(new Rectangle(width, v));
for (Rectangle lt : Rectangles) {
lt.update();
}
}
}
class Rectangle {
int x, y;
float v;
Rectangle(int x, float v) {
this.x = x;
this.v = v;
}
// display function
void display() {
fill(0, 99, 220);
rectMode(CENTER);
rect(x, 100, v, v);
}
void update() {
x = x-100;
}
}

calsign

Re: Assign value once to every object

1 year ago

I'm glad you finally figured it out... ArrayList is definitely a good way to do it.

I'll be sure to look at it when it's completed, but perhaps a better way to showcase your work is in the Share Your Work section.

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