CODEWITHSUNDEEP
processingphysics
Pedro Delfino
Pedro Delfino

Reputation: 2711

How to fix this Solar System model on processing?

I am trying to build a solar system model (only with the Earth, the Sun and the Moon) on Processing (version 3.4), using the Java Mode. I am new to processing and I have only used Java in this context (hence, I am also new to Java).

I have something which is partially working: enter image description here

That's my code. First tab:

Planet sun;

void setup() {
  size(900, 1200);
  sun = new Planet(100, 10, 0);
  sun.spawnMoons(1,2);
}

void draw() {
  background(0);
  translate(750, 900/2);
  sun.show();
  sun.orbit();
}

Second tab:

class Planet {
  float radius;
  float distance;
  Planet[] planets;
  float angle;
  float orbitspeed;

  Planet(float r, float d, float o) {
    radius = r;
    distance = 400;
    angle = PI;
    orbitspeed = o;
  }

  void orbit() {
    angle = angle + orbitspeed;
    if (planets != null) {
      for (int i = 0; i < planets.length; i++) {
        planets[i].orbit();
      }
    }
  }

  void spawnMoons(int total, int level) {
    planets = new Planet[total];
    for (int i = 0; i < planets.length; i++) {
      float r = radius/(level*2);
      float d = distance/(level*4);
      float o = 0.01;
      planets[i] = new Planet(r, d/(level*8), o);
      if (level < 3) {
        int num = 2;
        planets[i].spawnMoons(num, level+1);
      }
    }
  }

  void show() {
    pushMatrix();
    fill(255, 100);
    rotate(angle);
    translate(distance, 0);
    ellipse(0, 0, radius*2, radius*2);
    if (planets != null) {
      for (int i = 0; i < planets.length; i++) {
        planets[i].show();
      }
    }
    popMatrix();
  }
}

However, my "Moon" is too far from my "Earth". I am trying to fix it, but I can't. Considering the way I built it, if I change the value on 11st line (second tab), it won't solve the problem:

distance = 10;

Considering the way I built it, the distance between the Earth and the Sun it is the same as the distance between the Earth and its moon.

I was able to make the radius of each object proportional to each other. Nonetheless, I am failing to do the same with the distance between them. The line bellow was supposed to keep the proportionality on distance but it fails:

      float d = distance/(level*4);

How do I fix this?

Thanks.

Upvotes: 1

Views: 604

Answers (1)

J.D.
J.D.

Reputation: 4561

This is the error:

Planet(float r, float d, float o) {
  radius = r;
  distance = 400; //<== here
  angle = PI;
  orbitspeed = o;
}

In the constructor the distance for each new planet is set at 400, so the logic in spawnMoons() does nothing.

If you apply the changes below, it will work as you want and you can start tweaking ;)

//in setup()
sun = new Planet(100, 400, 0);
//in the planet constructor
distance = d;
//in spawnMoons()
float d = distance/level;
planets[i] = new Planet(r, d, o);

Upvotes: 2

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