// Transforms the matrix to make it look at the target
public void lookAt(Point eye, Point target, Vector up)
{
// Variables
Vector[] vec= new Vector[3];
vec[0]= eye-target;
vec[0].normalizeDest();
vec[0]*= -1;
vec[1]= up.getCrossProduct(vec[0]);
vec[1].normalizeDest();
vec[1]*= -1;
vec[2]= vec[0].getCrossProduct(vec[1]);
vec[2].normalizeDest();
vec[2]*= -1;
xx= vec[1].x;
xy= vec[1].y;
xz= vec[1].z;
yx= vec[2].x;
yy= vec[2].y;
yz= vec[2].z;
zx= vec[0].x;
zy= vec[0].y;
zz= vec[0].z;
ox= eye.x;
oy= eye.y;
oz= eye.z;
}
// Billboards the matrix
public void billboard(Point objPos, Point camPos, Vector camUp, Vector camForward)
{
// Variables
Vector right= (objPos-camPos);
float a= right.getMagnitudeSq();
Vector[] cross= new Vector[2];
if(a== 0f)
right= -camForward;
else
right= (Vector)(right*(1f/(float)Math.Sqrt(a)));
cross[0]= camUp.getCrossProduct(right);
cross[0].normalizeDest();
cross[1]= right.getCrossProduct(cross[0]);
resetToIdentityXO();
xx= cross[0].x;
xy= cross[0].y;
xz= cross[0].z;
yx= cross[1].x;
yy= cross[1].y;
yz= cross[1].z;
zx= right.x;
zy= right.y;
zz= right.z;
}