ENABLE_3DCONNEXION_DEVICES - 1st installment of support for 3Dconnexion devices

Implemented using hidapi library (https://github.com/libusb/hidapi) and https://github.com/koenieee/CrossplatformSpacemouseDriver/tree/master/SpaceMouseDriver as reference

Unsolved issues:

- When manipulating the SpaceNavigator wxWidgets generates a mouse wheel event that needs to be filtered out

- wxWidgets does not detect devices being connected/disconnected to the pc

- Current state forces a continuous rendering

- Current state misses dependence on camera zoom

- Non intuitive movement limits

- Translation and rotation speed factors are hardcoded

- Number of device buttons hardcoded

src/slic3r/GUI/Mouse3DController.hpp

@@ -0,0 +1,96 @@
+#ifndef slic3r_Mouse3DController_hpp_
+#define slic3r_Mouse3DController_hpp_
+
+#if ENABLE_3DCONNEXION_DEVICES
+
+#include "hidapi/hidapi.h"
+#include <thread>
+#include <mutex>
+#include <vector>
+
+namespace Slic3r {
+namespace GUI {
+
+class GLCanvas3D;
+
+class Mouse3DController
+{
+    class State
+    {
+        static const double DefaultTranslationScale;
+        static const float DefaultRotationScale;
+
+        mutable std::mutex m_mutex;
+
+        Vec3d m_translation;
+        Vec3f m_rotation;
+        std::vector<bool> m_buttons;
+
+        double m_translation_scale;
+        float m_rotation_scale;
+
+    public:
+        State();
+
+        void set_translation(const Vec3d& translation);
+        void set_rotation(const Vec3f& rotation);
+        void set_button(unsigned int id);
+
+        bool has_translation() const;
+        bool has_rotation() const;
+        bool has_any_button() const;
+
+        // return true if any change to the camera took place
+        bool apply(GLCanvas3D& canvas);
+    };
+
+    bool m_initialized;
+    State m_state;
+    std::thread m_thread;
+    GLCanvas3D* m_canvas;
+    std::mutex m_mutex;
+    hid_device* m_device;
+    bool m_running;
+
+public:
+    Mouse3DController();
+
+    void init();
+    void shutdown();
+
+    bool is_device_connected() const { return m_device != nullptr; }
+    bool is_running() const { return m_running; }
+
+    void set_canvas(GLCanvas3D* canvas)
+    {
+        std::lock_guard<std::mutex> lock(m_mutex);
+        m_canvas = canvas;
+    }
+
+    bool has_translation() const { return m_state.has_translation(); }
+    bool has_rotation() const { return m_state.has_rotation(); }
+    bool has_any_button() const { return m_state.has_any_button(); }
+
+    bool apply()
+    {
+        std::lock_guard<std::mutex> lock(m_mutex);
+        return (m_canvas != nullptr) ? m_state.apply(*m_canvas) : false;
+    }
+
+private:
+    void connect_device();
+    void disconnect_device();
+    void start();
+    void stop() { m_running = false; }
+
+    void run();
+    void collect_input();
+};
+
+} // namespace GUI
+} // namespace Slic3r
+
+#endif // ENABLE_3DCONNEXION_DEVICES
+
+#endif // slic3r_Mouse3DController_hpp_
+