| /* |
| * (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| * Unpublished-- rights reserved under the copyright laws of the |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. |
| */ |
| |
| #ifdef __cpluscplus |
| extern "C" { |
| #endif |
| |
| /* |
| * 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. |
| */ |
| void |
| trackball(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). |
| */ |
| void |
| add_quats(float *q1, float *q2, float *dest); |
| |
| /* |
| * A useful function, builds a rotation matrix in Matrix based on |
| * given quaternion. |
| */ |
| void |
| build_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. |
| */ |
| void |
| axis_to_quat(float a[3], float phi, float q[4]); |
| |
| #ifdef __cpluscplus |
| } |
| #endif |
