quaternion.cpp

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/*
 * quaternion.cpp
 *
 * Copyright (C) 2009  Thomas A. Vaughan
 * All rights reserved.
 *
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THOMAS A. VAUGHAN ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THOMAS A. VAUGHAN BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * Implementation of quaternion methods.  See quaternion.h
 */

// includes --------------------------------------------------------------------
#include "quaternion.h"         // always include our own header first

#include <math.h>



////////////////////////////////////////////////////////////////////////////////
//
//      static helper methods
//
////////////////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////////////////
//
//      public API
//
////////////////////////////////////////////////////////////////////////////////

void
quaternion_t::setEulerZYX
(
IN float yaw,
IN float pitch,
IN float roll
)
throw()
{
        // create quaternion based on Euler ZYX values
        // see bullet physics code or search online for examples
        float hY = 0.5 * yaw;           // hY: "half Yaw"
        float hP = 0.5 * pitch;         // hP: "half Pitch"
        float hR = 0.5 * roll;          // ...

        float cY = cos(hY);             // cY: cosine of half Yaw
        float sY = sin(hY);             // sY: sine of half Yaw
        float cP = cos(hP);             // ...
        float sP = sin(hP);
        float cR = cos(hR);
        float sR = sin(hR);

        // go ahead and set quaternion values based on trig results above
        x = sR * cP * cY - cR * sP * sY;
        y = cR * sP * cY + sR * cP * sY;
        z = cR * cP * sY - sR * sP * cY;
        w = cR * cP * cY + sR * sP * sY;
}