package torus;

  /**
  Simple 3d vector class with methods for simple operations.
  Used in torus demo        G. Hart Sept 2003.
  */

public class xyz {
  public float x, y, z;                          // extract as .x .y and .z

   xyz(float x0, float y0, float z0){            // constructor
     x=x0; y=y0; z=z0;
   }

   public xyz(int x0, int y0, int z0){           // constructor from ints
     x=(float)x0; y=(float)y0; z=(float)z0;
   }

   public String toString(){                     // "(x,y,z)" string form
     return "(" + Float.toString(this.x) + ","
                + Float.toString(this.y) + ","
                + Float.toString(this.z) + ")";
   }

   public static xyz plus(xyz a, xyz b){         // sum
     return new xyz(a.x+b.x, a.y+b.y, a.z+b.z);
   }

   public static xyz minus(xyz a, xyz b){        // difference
     return new xyz(a.x-b.x, a.y-b.y, a.z-b.z);
   }

   public static xyz scale(float a, xyz v){      // scalar prod
     return new xyz(a*v.x, a*v.y, a*v.z);
   }

   public static float dot(xyz a, xyz b){        // dot prod
     return a.x*b.x + a.y*b.y + a.z*b.z;
   }

   public static float mag2(xyz a){              // magnitude squared
     return a.x*a.x + a.y*a.y + a.z*a.z;
   }

   public static float mag(xyz a){               // magnitude
     return (float) Math.sqrt(a.x*a.x + a.y*a.y + a.z*a.z);
   }

   public static xyz unit(xyz v){                 // unit length
     return scale(1.0f/mag(v), v);                // we hope v isn't 0
   }

   public static xyz cross(xyz a, xyz b){         // cross product
     return new xyz(a.y*b.z - b.y*a.z,  a.z*b.x - b.z*a.x,  a.x*b.y - b.x*a.y);
   }

}