Feature/websocketnavigation (#882)

* Upgrade JSON Library
* Added support for navigation based on websocket communication

include/openspace/interaction/websocketinputstate.h

@@ -0,0 +1,125 @@
+/*****************************************************************************************
+ *                                                                                       *
+ * OpenSpace                                                                             *
+ *                                                                                       *
+ * Copyright (c) 2014-2019                                                               *
+ *                                                                                       *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
+ * software and associated documentation files (the "Software"), to deal in the Software *
+ * without restriction, including without limitation the rights to use, copy, modify,    *
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
+ * permit persons to whom the Software is furnished to do so, subject to the following   *
+ * conditions:                                                                           *
+ *                                                                                       *
+ * The above copyright notice and this permission notice shall be included in all copies *
+ * or substantial portions of the Software.                                              *
+ *                                                                                       *
+ * 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 OR COPYRIGHT    *
+ * HOLDERS 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.                                         *
+ ****************************************************************************************/
+
+#ifndef __OPENSPACE_CORE___WEBSOCKETINPUTSTATE___H__
+#define __OPENSPACE_CORE___WEBSOCKETINPUTSTATE___H__
+
+#include <ghoul/misc/stringconversion.h>
+#include <array>
+#include <memory>
+#include <unordered_map>
+#include <string>
+
+namespace openspace::interaction {
+
+/**
+ * Actions that any button of a websocket can have. Each button must be in one of these
+ * states
+ */
+enum class WebsocketAction : uint8_t {
+    /// Idle state if the button is unpressed and has been unpressed since last frame
+    Idle = 0,
+    /// If the button has been pressed since the last frame
+    Press,
+    /// If the button has been pressed since longer than last frame
+    Repeat,
+    /// If the button was released since the last frame
+    Release
+};
+
+/**
+ * The input state of a single websocket.
+ */
+struct WebsocketInputState {
+    /// The maximum number of supported axes
+    static constexpr const int MaxAxes = 10;
+    /// The maximum number of supported buttons
+    static constexpr const int MaxButtons = 32;
+
+    /// Marks whether this websocket is connected. If this value is \c false, all other
+    /// members of this struct are undefined
+    bool isConnected = false;
+
+    /// The name of this websocket
+    std::string name;
+
+    /// The number of axes that this websocket supports
+    int nAxes = 0;
+    /// The values for each axis. Each value is in the range [-1, 1]. Only the first
+    /// \c nAxes values are defined values, the rest are undefined
+    std::array<float, MaxAxes> axes;
+
+    /// The number of buttons that this websocket possesses
+    int nButtons = 0;
+    /// The status of each button. Only the first \c nButtons values are defined, the rest
+    /// are undefined
+    std::array<WebsocketAction, MaxButtons> buttons;
+};
+
+/// The maximum number of websockets that are supported by this system. This number is
+/// derived from the available GLFW constants
+constexpr const int MaxWebsockets = 16;
+//struct WebsocketInputStates : public std::array<WebsocketInputState, MaxWebsockets> {
+struct WebsocketInputStates : public std::unordered_map<size_t, WebsocketInputState*> {
+    /**
+     * This function adds the contributions of all connected websockets for the provided
+     * \p axis. After adding each websockets contribution, the result is clamped to [-1,1].
+     * If a websocket does not possess a particular axis, it's does not contribute to the
+     * sum.
+     *
+     * \param axis The numerical axis for which the values are added
+     * \return The summed axis values of all connected websockets
+     *
+     * \pre \p axis must be 0 or positive
+     */
+    float axis(int axis) const;
+
+    /**
+     * This functions checks whether any connected websocket has its \p button in the
+     * passed \p action. Any websocket that does not posses the \p button, it will be
+     * ignored.
+     *
+     * \param button The button that is to be checked
+     * \param action The action which is checked for each button
+     * \return \c true if there is at least one websocket whose \param button is in the
+     *         \p action state
+     *
+     * \pre \p button must be 0 or positive
+     */
+    bool button(int button, WebsocketAction action) const;
+};
+
+} // namespace openspace::interaction
+
+namespace ghoul {
+
+template <>
+std::string to_string(const openspace::interaction::WebsocketAction& action);
+
+template <>
+openspace::interaction::WebsocketAction from_string(const std::string& str);
+
+} // namespace ghoul
+
+#endif // __OPENSPACE_CORE___WEBSOCKETINPUTSTATE___H__