sceneorbiter.cpp

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/*
    Sheep - A Rigid Body Dynamics Engine
    Copyright (C) 2001-2004 Francois Beaune
    Contact: http://toxicengine.sourceforge.net/

    This file is part of Sheep.

    Sheep is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    Sheep is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Sheep; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "sceneorbiter.h"   // include first

using namespace sheep;

void SceneOrbiter::tumble(const Vector2 &delta) {
    Real dx = delta.m_x;

#ifdef REVERSE_AZIMUTH
    if(m_reverse_azimuth)
        dx = -dx;
#endif  // REVERSE_AZIMUTH

    m_azimuth = NormalizeAngle(m_azimuth + dx * PI / 2.0);
    m_elevation = NormalizeAngle(m_elevation - delta.m_y * PI / 2.0);
}

void SceneOrbiter::track(const Vector2 &delta) {
    const Real t = fabs(cos(m_elevation));

    const Vector3 w(cos(m_azimuth) * t, sin(m_elevation), sin(m_azimuth) * t);
    assert(w.IsUnitLength());

    Vector3 u(w.m_z, 0.0, -w.m_x);  // Vector3 u = Vector3(0.0, 1.0, 0.0) ^ w;
    u.Normalize();

    const Vector3 v = w ^ u;
    assert(v.IsUnitLength());

    m_center -= delta.m_x * u + delta.m_y * v;
}

void SceneOrbiter::dolly(const Vector2 &delta) {
    m_distance -= log(m_distance + 1.0) * delta.m_y;

    if(m_distance < 0.01)
        m_distance = 0.01;
}

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