class Cube {
  
  Point3D[] vertices = new Point3D[24];
  float w, h, d;

  Cube(){ }

  Cube(float w, float h, float d){
    this.w = w;
    this.h = h;
    this.d = d;

    // Cube composed of 6 quads
    // Front
    vertices[0] = new Point3D(-w/2,-h/2,d/2);
    vertices[1] = new Point3D(w/2,-h/2,d/2);
    vertices[2] = new Point3D(w/2,h/2,d/2);
    vertices[3] = new Point3D(-w/2,h/2,d/2);
    
    // Left
    vertices[4] = new Point3D(-w/2,-h/2,d/2);
    vertices[5] = new Point3D(-w/2,-h/2,-d/2);
    vertices[6] = new Point3D(-w/2,h/2,-d/2);
    vertices[7] = new Point3D(-w/2,h/2,d/2);
    
    // Right
    vertices[8] = new Point3D(w/2,-h/2,d/2);
    vertices[9] = new Point3D(w/2,-h/2,-d/2);
    vertices[10] = new Point3D(w/2,h/2,-d/2);
    vertices[11] = new Point3D(w/2,h/2,d/2);
    
    // Back
    vertices[12] = new Point3D(-w/2,-h/2,-d/2);  
    vertices[13] = new Point3D(w/2,-h/2,-d/2);
    vertices[14] = new Point3D(w/2,h/2,-d/2);
    vertices[15] = new Point3D(-w/2,h/2,-d/2);
    
    // Top
    vertices[16] = new Point3D(-w/2,-h/2,d/2);
    vertices[17] = new Point3D(-w/2,-h/2,-d/2);
    vertices[18] = new Point3D(w/2,-h/2,-d/2);
    vertices[19] = new Point3D(w/2,-h/2,d/2);
    
    // Bottom
    vertices[20] = new Point3D(-w/2,h/2,d/2);
    vertices[21] = new Point3D(-w/2,h/2,-d/2);
    vertices[22] = new Point3D(w/2,h/2,-d/2);
    vertices[23] = new Point3D(w/2,h/2,d/2);
  }

  void create(){
    for (int i=0; i<6; i++){
      beginShape(QUADS);
      for (int j = 0; j < 4; j++){
        vertex(vertices[j+4*i].x, vertices[j+4*i].y, vertices[j+4*i].z);
      }
      endShape();
    }
  }
}