Main Page   Modules   Class Hierarchy   Alphabetical List   Compound List   File List   Compound Members   File Members   Related Pages  

trackball.h

00001 /*
00002  * (c) Copyright 1993, 1994, Silicon Graphics, Inc.
00003  * ALL RIGHTS RESERVED
00004  * Permission to use, copy, modify, and distribute this software for
00005  * any purpose and without fee is hereby granted, provided that the above
00006  * copyright notice appear in all copies and that both the copyright notice
00007  * and this permission notice appear in supporting documentation, and that
00008  * the name of Silicon Graphics, Inc. not be used in advertising
00009  * or publicity pertaining to distribution of the software without specific,
00010  * written prior permission.
00011  *
00012  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
00013  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
00014  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
00015  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
00016  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
00017  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
00018  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
00019  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
00020  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
00021  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
00022  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
00023  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
00024  *
00025  * US Government Users Restricted Rights
00026  * Use, duplication, or disclosure by the Government is subject to
00027  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
00028  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
00029  * clause at DFARS 252.227-7013 and/or in similar or successor
00030  * clauses in the FAR or the DOD or NASA FAR Supplement.
00031  * Unpublished-- rights reserved under the copyright laws of the
00032  * United States.  Contractor/manufacturer is Silicon Graphics,
00033  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
00034  *
00035  * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
00036  */
00037 /*
00038  * trackball.h
00039  * A virtual trackball implementation
00040  * Written by Gavin Bell for Silicon Graphics, November 1988.
00041  */
00042 
00043 /*
00044  * Pass the x and y coordinates of the last and current positions of
00045  * the mouse, scaled so they are from (-1.0 ... 1.0).
00046  *
00047  * The resulting rotation is returned as a quaternion rotation in the
00048  * first paramater.
00049  */
00050 void
00051 trackball(float q[4], float p1x, float p1y, float p2x, float p2y);
00052 
00053 void
00054 negate_quat(float *q, float *qn);
00055 
00056 /*
00057  * Given two quaternions, add them together to get a third quaternion.
00058  * Adding quaternions to get a compound rotation is analagous to adding
00059  * translations to get a compound translation.  When incrementally
00060  * adding rotations, the first argument here should be the new
00061  * rotation, the second and third the total rotation (which will be
00062  * over-written with the resulting new total rotation).
00063  */
00064 void
00065 add_quats(float *q1, float *q2, float *dest);
00066 
00067 /*
00068  * A useful function, builds a rotation matrix in Matrix based on
00069  * given quaternion.
00070  */
00071 void
00072 build_rotmatrix(float m[4][4], float q[4]);
00073 
00074 /*
00075  * This function computes a quaternion based on an axis (defined by
00076  * the given vector) and an angle about which to rotate.  The angle is
00077  * expressed in radians.  The result is put into the third argument.
00078  */
00079 void
00080 axis_to_quat(float a[3], float phi, float q[4]);
00081 

Generated at Fri Oct 12 15:12:21 2001 for GLVU by doxygen1.2.10 written by Dimitri van Heesch, © 1997-2001