/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file look_at_src.h
 * @author drose
 * @date 1999-09-25
 */

// These functions return a matrix that rotates between a coordinate system
// defined with the given forward and up vectors, and the standard coordinate
// system with y-forward and z-up.  They differ only in their behavior when
// the supplied forward and up vectors are not perpendicular; in this case,
// look_at will match the forward vector precisely, while heads_up will match
// the up vector precisely.

// Since these functions only return a rotation matrix, the translation
// component is always zero.  There are flavors of these functions that simply
// return the upper 3x3 part of the matrix, and flavors that return the whole
// 4x4 matrix with a zero bottom row.

BEGIN_PUBLISH

EXPCL_PANDA_MATHUTIL void
heads_up(FLOATNAME(LMatrix3) &mat, const FLOATNAME(LVector3) &fwd,
         const FLOATNAME(LVector3) &up = FLOATNAME(LVector3)::up(),
         CoordinateSystem cs = CS_default);
EXPCL_PANDA_MATHUTIL void
look_at(FLOATNAME(LMatrix3) &mat, const FLOATNAME(LVector3) &fwd,
        const FLOATNAME(LVector3) &up = FLOATNAME(LVector3)::up(),
        CoordinateSystem cs = CS_default);

INLINE_MATHUTIL void
heads_up(FLOATNAME(LMatrix3) &mat, const FLOATNAME(LVector3) &fwd,
         CoordinateSystem cs);
INLINE_MATHUTIL void
look_at(FLOATNAME(LMatrix3) &mat, const FLOATNAME(LVector3) &fwd,
        CoordinateSystem cs);


INLINE_MATHUTIL void
heads_up(FLOATNAME(LMatrix4) &mat, const FLOATNAME(LVector3) &fwd,
         const FLOATNAME(LVector3) &up = FLOATNAME(LVector3)::up(),
         CoordinateSystem cs = CS_default);
INLINE_MATHUTIL void
look_at(FLOATNAME(LMatrix4) &mat, const FLOATNAME(LVector3) &fwd,
        const FLOATNAME(LVector3) &up = FLOATNAME(LVector3)::up(),
        CoordinateSystem cs = CS_default);

INLINE_MATHUTIL void
heads_up(FLOATNAME(LMatrix4) &mat, const FLOATNAME(LVector3) &fwd,
         CoordinateSystem cs);
INLINE_MATHUTIL void
look_at(FLOATNAME(LMatrix4) &mat, const FLOATNAME(LVector3) &fwd,
        CoordinateSystem cs);



INLINE_MATHUTIL void
heads_up(FLOATNAME(LQuaternion) &quat, const FLOATNAME(LVector3) &fwd,
         const FLOATNAME(LVector3) &up = FLOATNAME(LVector3)::up(),
         CoordinateSystem cs = CS_default);
INLINE_MATHUTIL void
look_at(FLOATNAME(LQuaternion) &quat, const FLOATNAME(LVector3) &fwd,
        const FLOATNAME(LVector3) &up = FLOATNAME(LVector3)::up(),
        CoordinateSystem cs = CS_default);

INLINE_MATHUTIL void
heads_up(FLOATNAME(LQuaternion) &quat, const FLOATNAME(LVector3) &fwd,
         CoordinateSystem cs);
INLINE_MATHUTIL void
look_at(FLOATNAME(LQuaternion) &quat, const FLOATNAME(LVector3) &fwd,
        CoordinateSystem cs);

END_PUBLISH

#include "look_at_src.I"