opengl/trackball.h

   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  31  * Unpublished-- rights reserved under the copyright laws of the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 #ifndef TRACKBALL_H
  44 #define TRACKBALL_H
  45
  46
  47 /*
  48  * Pass the x and y coordinates of the last and current positions of
  49  * the mouse, scaled so they are from (-1.0 ... 1.0).
  50  *
  51  * The resulting rotation is returned as a quaternion rotation in the
  52  * first paramater.
  53  */
  54 void
  55 trackball(float q[4], float p1x, float p1y, float p2x, float p2y);
  56
  57 /*
  58  * Given two quaternions, add them together to get a third quaternion.
  59  * Adding quaternions to get a compound rotation is analagous to adding
  60  * translations to get a compound translation.  When incrementally
  61  * adding rotations, the first argument here should be the new
  62  * rotation, the second and third the total rotation (which will be
  63  * over-written with the resulting new total rotation).
  64  */
  65 void
  66 add_quats(const float q1[4], const float q2[4], float dest[4]);
  67
  68 /*
  69  * A useful function, builds a rotation matrix in Matrix based on
  70  * given quaternion.
  71  */
  72 void
  73 build_rotmatrix(float m[4][4], const float q[4]);
  74
  75 /*
  76  * This function computes a quaternion based on an axis (defined by
  77  * the given vector) and an angle about which to rotate.  The angle is
  78  * expressed in radians.  The result is put into the third argument.
  79  */
  80 void
  81 axis_to_quat(const float a[3], float phi, float q[4]);
  82
  83
  84 #endif /* TRACKBALL_H */