src/qvgui/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00031  * Unpublished-- rights reserved under the copyright laws of the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 #ifndef _TRACKBALL_H
00044 #define _TRACKBALL_H
00045 
00046 #ifdef __cplusplus
00047 extern "C" {
00048 #endif
00049 
00050 /*
00051  * Pass the x and y coordinates of the last and current positions of
00052  * the mouse, scaled so they are from (-1.0 ... 1.0).
00053  *
00054  * The resulting rotation is returned as a quaternion rotation in the
00055  * first paramater.
00056  */
00057 void
00058 trackball(float q[4], float p1x, float p1y, float p2x, float p2y);
00059 
00060 /*
00061  * Given two quaternions, add them together to get a third quaternion.
00062  * Adding quaternions to get a compound rotation is analagous to adding
00063  * translations to get a compound translation.  When incrementally
00064  * adding rotations, the first argument here should be the new
00065  * rotation, the second and third the total rotation (which will be
00066  * over-written with the resulting new total rotation).
00067  */
00068 void
00069 add_quats(float *q1, float *q2, float *dest);
00070 
00071 /*
00072  * A useful function, builds a rotation matrix in Matrix based on
00073  * given quaternion.
00074  */
00075 void
00076 build_rotmatrix(float m[4][4], float q[4]);
00077 
00078 /*
00079  * This function computes a quaternion based on an axis (defined by
00080  * the given vector) and an angle about which to rotate.  The angle is
00081  * expressed in radians.  The result is put into the third argument.
00082  */
00083 void
00084 axis_to_quat(float a[3], float phi, float q[4]);
00085 
00086 #ifdef __cplusplus
00087 }
00088 #endif
00089 
00090 #endif /* _TRACKBALL_H */

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