/* * (c) Copyright 1993, 1994, Silicon Graphics, Inc. * ALL RIGHTS RESERVED * Permission to use, copy, modify, and distribute this software for * any purpose and without fee is hereby granted, provided that the above * copyright notice appear in all copies and that both the copyright notice * and this permission notice appear in supporting documentation, and that * the name of Silicon Graphics, Inc. not be used in advertising * or publicity pertaining to distribution of the software without specific, * written prior permission. * * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE. * * US Government Users Restricted Rights * Use, duplication, or disclosure by the Government is subject to * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph * (c)(1)(ii) of the Rights in Technical Data and Computer Software * clause at DFARS 252.227-7013 and/or in similar or successor * clauses in the FAR or the DOD or NASA FAR Supplement. * Unpublished-- rights reserved under the copyright laws of the * United States.  Contractor/manufacturer is Silicon Graphics, * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311. * * OpenGL(TM) is a trademark of Silicon Graphics, Inc. *//* * trackball.h * A virtual trackball implementation * Written by Gavin Bell for Silicon Graphics, November 1988. *//* * Pass the x and y coordinates of the last and current positions of * the mouse, scaled so they are from (-1.0 ... 1.0). * * The resulting rotation is returned as a quaternion rotation in the * first paramater. */voidtrackball(float q[4], float p1x, float p1y, float p2x, float p2y);/* * Given two quaternions, add them together to get a third quaternion. * Adding quaternions to get a compound rotation is analagous to adding * translations to get a compound translation.  When incrementally * adding rotations, the first argument here should be the new * rotation, the second and third the total rotation (which will be * over-written with the resulting new total rotation). */voidadd_quats(float *q1, float *q2, float *dest);/* * A useful function, builds a rotation matrix in Matrix based on * given quaternion. */voidbuild_rotmatrix(float m[4][4], float q[4]);/* * This function computes a quaternion based on an axis (defined by * the given vector) and an angle about which to rotate.  The angle is * expressed in radians.  The result is put into the third argument. */voidaxis_to_quat(float a[3], float phi, float q[4]);