3D Programming Tricks - Beginning Android Games - page 526

Listing 11-1. Vector3.java, a Vector in 3D
package com.badlogic.androidgames.framework.math;
import android.opengl.Matrix;
import android.util.FloatMath;
public class Vector3 {
private static final float [] matrix = new float [16];
private static final float [] inVec = new float [4];
private static final float [] outVec = new float [4];
public float x, y, z;
The class starts with a couple of private static final float arrays. We'll need them later on when
we implement the new rotate() method of our Vector3 class. Just remember that the matrix
member has 16 elements and the inVec and outVec members each have 4 elements. We create
those three arrays so that we don't have to create them later on, all the time. This will keep the
garbage collector happy. Just remember that by doing so, the Vector3 class is not thread safe!
The x , y , and z members defined next should be self-explanatory. They store the actual
components of the vector:
public Vector3() {
}
public Vector3( float x, float y, float z) {
this .x = x;
this .y = y;
this .z = z;
}
public Vector3(Vector3 other) {
this .x = other.x;
this .y = other.y;
this .z = other.z;
}
public Vector3 cpy() {
return new Vector3(x, y, z);
}
public Vector3 set( float x, float y, float z) {
this .x = x;
this .y = y;
this .z = z;
return this ;
}
public Vector3 set(Vector3 other) {
this .x = other.x;
this .y = other.y;