ArcBall.h

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#ifndef Magnum_Examples_ArcBall_h
#define Magnum_Examples_ArcBall_h
/*
    This file is part of Magnum.
 
    Original authors — credit is appreciated but not required:
 
        2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
        2020, 2021, 2022 — Vladimír Vondruš <mosra@centrum.cz>
        2020 — Nghia Truong <nghiatruong.vn@gmail.com>
 
    This is free and unencumbered software released into the public domain.
 
    Anyone is free to copy, modify, publish, use, compile, sell, or distribute
    this software, either in source code form or as a compiled binary, for any
    purpose, commercial or non-commercial, and by any means.
 
    In jurisdictions that recognize copyright laws, the author or authors of
    this software dedicate any and all copyright interest in the software to
    the public domain. We make this dedication for the benefit of the public
    at large and to the detriment of our heirs and successors. We intend this
    dedication to be an overt act of relinquishment in perpetuity of all
    present and future rights to this software under copyright law.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
#include <Magnum/Magnum.h>
#include <Magnum/Math/Functions.h>
#include <Magnum/Math/DualQuaternion.h>
#include <Magnum/Math/Vector2.h>
#include <Magnum/Math/Vector3.h>
 
using namespace Magnum;
 
class ArcBall {
    public:
        ArcBall(const Vector3& cameraPosition, const Vector3& viewCenter,
            const Vector3& upDir, Deg fov, const Vector2i& windowSize);
 
        void setViewParameters(const Vector3 &eye, const Vector3 &viewCenter,
                              const Vector3 &upDir);
 
        void reset();
 
        void reshape(const Vector2i& windowSize) { _windowSize = windowSize; }
 
        bool updateTransformation();
 
        Float lagging() const { return _lagging; }
 
        void setLagging(Float lagging);
 
        void initTransformation(const Vector2i &mousePos);
 
        void rotate(const Vector2i &mousePos);
 
        void translate(const Vector2i &mousePos);
 
        void translateDelta(const Vector2 &translationNDC);
 
        void zoom(Float delta);
 
        Deg fov() const { return _fov; }
 
        const DualQuaternion& view() const { return _view; }
 
        Matrix4 viewMatrix() const { return _view.toMatrix(); }
 
        Matrix4 inverseViewMatrix() const {
            return _inverseView.toMatrix();
        }
 
        const DualQuaternion& transformation() const { return _inverseView; }
 
        Matrix4 transformationMatrix() const { return _inverseView.toMatrix(); }
 
        Float viewDistance() const { return Math::abs(_targetZooming); }
 
    protected:
        void updateInternalTransformations();
 
        Vector2 screenCoordToNDC(const Vector2i &mousePos) const;
 
        Deg _fov;
        Vector2i _windowSize;
 
        Vector2 _prevMousePosNDC;
        Float _lagging{};
 
        Vector3 _targetPosition, _currentPosition, _positionT0;
        Quaternion _targetQRotation, _currentQRotation, _qRotationT0;
        Float _targetZooming, _currentZooming, _zoomingT0;
        DualQuaternion _view, _inverseView;
};
 
#endif