ArcballCam.hpp

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#ifndef CSCI441_ARCBALL_CAM_HPP
#define CSCI441_ARCBALL_CAM_HPP
 
#include "PerspectiveCamera.hpp"
 
namespace CSCI441 {
 
    class ArcballCam final : public CSCI441::PerspectiveCamera {
    public:
        explicit ArcballCam(GLfloat minRadius = 2.0f, GLfloat maxRadius = 30.0f, GLfloat aspectRatio = 1.0f, GLfloat fovy = 45.0f, GLfloat nearClipPlane = 0.001f, GLfloat farClipPlane = 1000.0f);
 
        void recomputeOrientation() final;
 
        void moveForward(GLfloat movementFactor) final;
 
        void moveBackward(GLfloat movementFactor) final;
 
    private:
        void _updateArcballCameraViewMatrix();
 
        void _clampRadius();
 
        GLfloat _minRadius;
        GLfloat _maxRadius;
    };
}
 
inline CSCI441::ArcballCam::ArcballCam(
        const GLfloat minRadius,
        const GLfloat maxRadius,
        const GLfloat aspectRatio,
        const GLfloat fovy,
        const GLfloat nearClipPlane,
        const GLfloat farClipPlane
) : CSCI441::PerspectiveCamera(aspectRatio, fovy, nearClipPlane, farClipPlane),
    _minRadius(minRadius),
    _maxRadius(maxRadius)
{
    recomputeOrientation();
}
 
inline void CSCI441::ArcballCam::recomputeOrientation() {
    // compute direction vector based on spherical to cartesian conversion
    mCameraDirection.x =  glm::sin(mCameraTheta ) * glm::sin(mCameraPhi ) * mCameraRadius;
    mCameraDirection.y = -glm::cos(mCameraPhi )                                  * mCameraRadius;
    mCameraDirection.z = -glm::cos(mCameraTheta ) * glm::sin(mCameraPhi ) * mCameraRadius;
 
    _updateArcballCameraViewMatrix();
}
 
inline void CSCI441::ArcballCam::moveForward(const GLfloat movementFactor) {
    mCameraRadius -= movementFactor;    // camera "moves forward" by reducing the radius to get closer to the look at point
    _clampRadius();                     // ensure camera doesn't get too close
    recomputeOrientation();             // update view matrix
}
 
inline void CSCI441::ArcballCam::moveBackward(const GLfloat movementFactor) {
    mCameraRadius += movementFactor;    // camera "moves backward" by increasing the radius to get further away from the look at point
    _clampRadius();                     // ensure camera doesn't get too far away
    recomputeOrientation();             // update view matrix
}
 
inline void CSCI441::ArcballCam::_updateArcballCameraViewMatrix() {
    setPosition(mCameraLookAtPoint + mCameraDirection );
    computeViewMatrix();
}
 
inline void CSCI441::ArcballCam::_clampRadius() {
    mCameraRadius = glm::clamp(mCameraRadius, _minRadius, _maxRadius);
}
 
#endif // CSCI441_ARCBALL_CAM_HPP