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