132001f49Smrg/* 232001f49Smrg * (c) Copyright 1993, 1994, Silicon Graphics, Inc. 332001f49Smrg * ALL RIGHTS RESERVED 432001f49Smrg * Permission to use, copy, modify, and distribute this software for 532001f49Smrg * any purpose and without fee is hereby granted, provided that the above 632001f49Smrg * copyright notice appear in all copies and that both the copyright notice 732001f49Smrg * and this permission notice appear in supporting documentation, and that 832001f49Smrg * the name of Silicon Graphics, Inc. not be used in advertising 932001f49Smrg * or publicity pertaining to distribution of the software without specific, 1032001f49Smrg * written prior permission. 1132001f49Smrg * 1232001f49Smrg * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" 1332001f49Smrg * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, 1432001f49Smrg * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR 1532001f49Smrg * FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON 1632001f49Smrg * GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, 1732001f49Smrg * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY 1832001f49Smrg * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, 1932001f49Smrg * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF 2032001f49Smrg * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN 2132001f49Smrg * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON 2232001f49Smrg * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE 2332001f49Smrg * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE. 2432001f49Smrg * 2532001f49Smrg * US Government Users Restricted Rights 2632001f49Smrg * Use, duplication, or disclosure by the Government is subject to 2732001f49Smrg * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph 2832001f49Smrg * (c)(1)(ii) of the Rights in Technical Data and Computer Software 2932001f49Smrg * clause at DFARS 252.227-7013 and/or in similar or successor 3032001f49Smrg * clauses in the FAR or the DOD or NASA FAR Supplement. 3132001f49Smrg * Unpublished-- rights reserved under the copyright laws of the 3232001f49Smrg * United States. Contractor/manufacturer is Silicon Graphics, 3332001f49Smrg * Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311. 3432001f49Smrg * 3532001f49Smrg * OpenGL(TM) is a trademark of Silicon Graphics, Inc. 3632001f49Smrg */ 3732001f49Smrg/* 3832001f49Smrg * trackball.h 3932001f49Smrg * A virtual trackball implementation 4032001f49Smrg * Written by Gavin Bell for Silicon Graphics, November 1988. 4132001f49Smrg */ 4232001f49Smrg 4332001f49Smrg#ifndef TRACKBALL_H 4432001f49Smrg#define TRACKBALL_H 4532001f49Smrg 4632001f49Smrg 4732001f49Smrg/* 4832001f49Smrg * Pass the x and y coordinates of the last and current positions of 4932001f49Smrg * the mouse, scaled so they are from (-1.0 ... 1.0). 5032001f49Smrg * 5132001f49Smrg * The resulting rotation is returned as a quaternion rotation in the 5232001f49Smrg * first paramater. 5332001f49Smrg */ 5432001f49Smrgvoid 5532001f49Smrgtrackball(float q[4], float p1x, float p1y, float p2x, float p2y); 5632001f49Smrg 5732001f49Smrg/* 5832001f49Smrg * Given two quaternions, add them together to get a third quaternion. 5932001f49Smrg * Adding quaternions to get a compound rotation is analagous to adding 6032001f49Smrg * translations to get a compound translation. When incrementally 6132001f49Smrg * adding rotations, the first argument here should be the new 6232001f49Smrg * rotation, the second and third the total rotation (which will be 6332001f49Smrg * over-written with the resulting new total rotation). 6432001f49Smrg */ 6532001f49Smrgvoid 6632001f49Smrgadd_quats(const float q1[4], const float q2[4], float dest[4]); 6732001f49Smrg 6832001f49Smrg/* 6932001f49Smrg * A useful function, builds a rotation matrix in Matrix based on 7032001f49Smrg * given quaternion. 7132001f49Smrg */ 7232001f49Smrgvoid 7332001f49Smrgbuild_rotmatrix(float m[4][4], const float q[4]); 7432001f49Smrg 7532001f49Smrg/* 7632001f49Smrg * This function computes a quaternion based on an axis (defined by 7732001f49Smrg * the given vector) and an angle about which to rotate. The angle is 7832001f49Smrg * expressed in radians. The result is put into the third argument. 7932001f49Smrg */ 8032001f49Smrgvoid 8132001f49Smrgaxis_to_quat(const float a[3], float phi, float q[4]); 8232001f49Smrg 8332001f49Smrg 8432001f49Smrg#endif /* TRACKBALL_H */ 85