ENU basis

enu.js

function ENUBasis(p)
{
	// Up is vector from origin
	var z = vec3.create();
	vec3.normalize(z, p);
	
	var y = vec3.create();
	vec3.set(y, 0, 1, 0);

	var x = vec3.create();	
	vec3.cross(x, z, y);
	vec3.normalize(x, x);
	
	vec3.cross(y, x, z);
	vec3.normalize(y, y);

	
	// Create basis matrix
	var basis = mat3.create();
	basis[0] = x[0];
	basis[1] = x[1];
	basis[2] = x[2];
	basis[3] = y[0];
	basis[4] = y[1];
	basis[5] = y[2];
	basis[6] = z[0];
	basis[7] = z[1];
	basis[8] = z[2];
	
	return basis;
}