From 96715484242760e771339a018ea187d7c7827588 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Mon, 26 Jun 2006 22:59:28 +0000 Subject: virtual trackball code --- progs/util/trackball.h | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 progs/util/trackball.h (limited to 'progs/util/trackball.h') diff --git a/progs/util/trackball.h b/progs/util/trackball.h new file mode 100644 index 0000000..9b27864 --- /dev/null +++ b/progs/util/trackball.h @@ -0,0 +1,84 @@ +/* + * (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 + * Unpublished-- rights reserved under the copyright laws of the + * United States.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. + */ + +#ifndef TRACKBALL_H +#define TRACKBALL_H + + +/* + * 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(const float q1[4], const float q2[4], float dest[4]); + +/* + * A useful function, builds a rotation matrix in Matrix based on + * given quaternion. + */ +void +build_rotmatrix(float m[4][4], const 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(const float a[3], float phi, float q[4]); + + +#endif /* TRACKBALL_H */ -- cgit v1.1