tutorial: trackball.h

File trackball.h, 3.2 KB (added by leon, 6 years ago)

Header for trackball

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1/*
2 * (c) Copyright 1993, 1994, Silicon Graphics, Inc.
3 * ALL RIGHTS RESERVED
4 * Permission to use, copy, modify, and distribute this software for
5 * any purpose and without fee is hereby granted, provided that the above
6 * copyright notice appear in all copies and that both the copyright notice
7 * and this permission notice appear in supporting documentation, and that
8 * the name of Silicon Graphics, Inc. not be used in advertising
9 * or publicity pertaining to distribution of the software without specific,
10 * written prior permission.
11 *
12 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
13 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
14 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
15 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
16 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
17 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
18 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
19 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
20 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
21 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
22 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
23 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
24 *
25 * US Government Users Restricted Rights
26 * Use, duplication, or disclosure by the Government is subject to
27 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
28 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
29 * clause at DFARS 252.227-7013 and/or in similar or successor
30 * clauses in the FAR or the DOD or NASA FAR Supplement.
31 * Unpublished-- rights reserved under the copyright laws of the
32 * United States.  Contractor/manufacturer is Silicon Graphics,
33 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
34 *
35 * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
36 */
37/*
38 * trackball.h
39 * A virtual trackball implementation
40 * Written by Gavin Bell for Silicon Graphics, November 1988.
41 */
42
43/*
44 * Pass the x and y coordinates of the last and current positions of
45 * the mouse, scaled so they are from (-1.0 ... 1.0).
46 *
47 * The resulting rotation is returned as a quaternion rotation in the
48 * first paramater.
49 */
50void trackball(float q[4], float p1x, float p1y, float p2x, float p2y);
51
52/*
53 * Given two quaternions, add them together to get a third quaternion.
54 * Adding quaternions to get a compound rotation is analagous to adding
55 * translations to get a compound translation.  When incrementally
56 * adding rotations, the first argument here should be the new
57 * rotation, the second and third the total rotation (which will be
58 * over-written with the resulting new total rotation).
59 */
60void add_quats(float *q1, float *q2, float *dest);
61
62/*
63 * A useful function, builds a rotation matrix in Matrix based on
64 * given quaternion.
65 */
66void build_rotmatrix(float m[4][4], float q[4]);
67
68/*
69 * This function computes a quaternion based on an axis (defined by
70 * the given vector) and an angle about which to rotate.  The angle is
71 * expressed in radians.  The result is put into the third argument.
72 */
73void axis_to_quat(float a[3], float phi, float q[4]);
74
75