//! Align an Entity, so the X axis is pointing along
//! the global direction x,y,z.
//! The up vector will be the Y axis.
// \param entity - entity to align
// \param x,y,z  - direction to align
// \param glob   - global alignment (ignore parent rotation)
FUNCTION EntityAlignVector%: entity%, x,y,z, glob%=FALSE
LOCAL m[]
LOCAL d

	ASSERT EntityIsValid(entity)
	m[] = g3DObj[entity].M[]

	d = x*x + y*y + z*z
	// must normalize before?
	IF ABS(d-1.0) > 0.01
		IF ABS(d)<0.0000001
			x=1
			y=0
			z=0
		ELSE
			d = 1.0 / SQR(d)
			x=x*d
			y=y*d
			z=z*d
		ENDIF
	ENDIF

	d=z

	// X
    m[ 0]=z
	m[ 1]=0
	m[ 2]=-x

	// Z
	m[8]=x
	m[9]=y
	m[10]=z

	// Y = ZxX
	m[4] = m[ 9]*m[2] - m[10]*m[1]
	m[5] = m[10]*m[0] - m[ 8]*m[2]
	m[6] = m[ 8]*m[1] - m[ 9]*m[0]

	IF glob AND g3DObj[entity].parent>=0
		LOCAL pm[]
		EntityInverseMatrix(g3DObj[EntityGetParent(entity)].Mg[], pm[])
		LOCAL x,y,z
		x=m[12]
		y=m[13]
		z=m[14]
		EntityMultMatrix4x4(g3DObj[entity].M[], pm[], m[])
		g3DObj[entity].M[12]=x
		g3DObj[entity].M[13]=y
		g3DObj[entity].M[14]=z

	ELSE
		g3DObj[entity].M[] = m[]
	ENDIF
	EntityUpdateMatrix(g3DObj[entity])
ENDFUNCTION