magnum/src/Magnum/Platform/AbstractXApplication.h

#ifndef Magnum_Platform_AbstractXApplication_h
#define Magnum_Platform_AbstractXApplication_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022, 2023 Vladimír Vondruš <mosra@centrum.cz>
    Copyright © 2019, 2020 Konstantinos Chatzilygeroudis <costashatz@gmail.com>

    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.
*/

/** @file
 * @brief Class @ref Magnum::Platform::AbstractXApplication
 */

#include "Magnum/configure.h"

#ifdef MAGNUM_TARGET_GL
#include <Corrade/Containers/EnumSet.h>
#include <Corrade/Containers/Optional.h>
#include <Corrade/Containers/Pointer.h>
#include <Corrade/Containers/String.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>
/* undef Xlib nonsense to avoid conflicts */
#undef Always
#undef Bool
#undef Complex
#undef Convex
#undef None
#undef Status
#undef Success
#undef Button1
#undef Button2
#undef Button3
#undef Button4
#undef Button5

#ifndef DOXYGEN_GENERATING_OUTPUT
/* Unfortunately Xlib *needs* the Bool type, so provide a typedef instead */
typedef int Bool;
#endif

#include "Magnum/Magnum.h"
#include "Magnum/Tags.h"
#include "Magnum/Math/Vector2.h"
#include "Magnum/Platform/GLContext.h"

#ifdef MAGNUM_BUILD_DEPRECATED
/* Some APIs used to take or return a std::string before */
#include <Corrade/Containers/StringStl.h>
#endif

namespace Magnum { namespace Platform {

namespace Implementation {
    template<class, class, class, class> class AbstractContextHandler;
}

/** @nosubgrouping
@brief Base for X11-based applications

Supports keyboard and mouse handling. See @ref platform for brief introduction.

@note Not meant to be used directly, see the @ref GlxApplication and
    @ref XEglApplication subclasses instead.

@note This class is available only if Magnum is compiled with
    @ref MAGNUM_TARGET_GL enabled (done by default). See @ref building-features
    for more information.
*/
class AbstractXApplication {
    public:
        /** @brief Application arguments */
        struct Arguments {
            /** @brief Constructor */
            /*implicit*/ constexpr Arguments(int& argc, char** argv) noexcept: argc{argc}, argv{argv} {}

            int& argc;      /**< @brief Argument count */
            char** argv;    /**< @brief Argument values */
        };

        class Configuration;
        class GLConfiguration;
        class ViewportEvent;
        class InputEvent;
        class KeyEvent;
        class MouseEvent;
        class MouseMoveEvent;

        /** @brief Copying is not allowed */
        AbstractXApplication(const AbstractXApplication&) = delete;

        /** @brief Moving is not allowed */
        AbstractXApplication(AbstractXApplication&&) = delete;

        /** @brief Copying is not allowed */
        AbstractXApplication& operator=(const AbstractXApplication&) = delete;

        /** @brief Moving is not allowed */
        AbstractXApplication& operator=(AbstractXApplication&&) = delete;

        /**
         * @brief Execute main loop
         * @return Value for returning from @cpp main() @ce
         *
         * Calls @ref mainLoopIteration() in a loop until @ref exit() is
         * called. See @ref MAGNUM_GLXAPPLICATION_MAIN() or
         * @ref MAGNUM_XEGLAPPLICATION_MAIN() for usage information.
         */
        int exec();

        /**
         * @brief Run one iteration of application main loop
         * @return @cpp false @ce if @ref exit() was called and the application
         *      should exit, @cpp true @ce otherwise
         * @m_since{2020,06}
         *
         * Called internally from @ref exec(). If you want to have better
         * control over how the main loop behaves, you can call this function
         * yourself from your own `main()` function instead of it being called
         * automatically from @ref exec() / @ref MAGNUM_GLXAPPLICATION_MAIN()
         * / @ref MAGNUM_XEGLAPPLICATION_MAIN().
         */
        bool mainLoopIteration();

        /**
         * @brief Exit application
         * @param exitCode  The exit code the application should return
         *
         * When called from application constructor, it will cause the
         * application to exit immediately after constructor ends, without any
         * events being processed. Calling this function is recommended over
         * @ref std::exit() or @ref Corrade::Utility::Fatal "Fatal", which exit
         * without calling destructors on local scope. Note that, however, you
         * need to explicitly @cpp return @ce after calling it, as it can't
         * exit the constructor on its own:
         *
         * @snippet Platform.cpp exit-from-constructor
         *
         * When called from the main loop, the application exits cleanly
         * before next main loop iteration is executed.
         */
        void exit(int exitCode = 0) {
            _flags |= Flag::Exit;
            _exitCode = exitCode;
        }

    protected:
        /* Nobody will need to have (and delete) AbstractXApplication*, thus
           this is faster than public pure virtual destructor */
        ~AbstractXApplication();

        /**
         * @brief Create a window with given configuration for OpenGL context
         * @param configuration     Application configuration
         * @param glConfiguration   OpenGL context configuration
         *
         * Must be called only if the context wasn't created by the constructor
         * itself, i.e. when passing @ref NoCreate to it. Error message is
         * printed and the program exits if the context cannot be created, see
         * @ref tryCreate() for an alternative.
         */
        void create(const Configuration& configuration, const GLConfiguration& glConfiguration);

        /**
         * @brief Create a window with given configuration and OpenGL context
         *
         * Equivalent to calling @ref create(const Configuration&, const GLConfiguration&)
         * with default-constructed @ref GLConfiguration.
         */
        void create(const Configuration& configuration);

        /**
         * @brief Create a window with default configuration and OpenGL context
         *
         * Equivalent to calling @ref create(const Configuration&) with
         * default-constructed @ref Configuration.
         */
        void create();

        /**
         * @brief Try to create context with given configuration for OpenGL context
         *
         * Unlike @ref create(const Configuration&, const GLConfiguration&)
         * returns @cpp false @ce if the context cannot be created,
         * @cpp true @ce otherwise.
         */
        bool tryCreate(const Configuration& configuration, const GLConfiguration& glConfiguration);

        /**
         * @brief Try to create context with given configuration and OpenGL context
         *
         * Unlike @ref create(const Configuration&) returns @cpp false @ce if
         * the context cannot be created, @cpp true @ce otherwise.
         */
        bool tryCreate(const Configuration& configuration);

        /** @{ @name Screen handling */

    public:
        /**
         * @brief Window size
         *
         * Window size to which all input event coordinates can be related.
         * Same as @ref framebufferSize().
         */
        Vector2i windowSize() const { return _windowSize; }

        /**
         * @brief Framebuffer size
         *
         * Size of the default framebuffer. Same as @ref windowSize().
         */
        Vector2i framebufferSize() const { return _windowSize; }

    protected:
        /**
         * @brief Swap buffers
         *
         * Paints currently rendered framebuffer on screen.
         */
        void swapBuffers();

        /** @copydoc Sdl2Application::redraw() */
        void redraw() { _flags |= Flag::Redraw; }

    private:
        /**
         * @brief Viewport event
         *
         * Called when window size changes. The default implementation does
         * nothing. If you want to respond to size changes, you should pass the
         * new size to @ref GL::DefaultFramebuffer::setViewport() (if using
         * OpenGL) and possibly elsewhere (to
         * @ref SceneGraph::Camera::setViewport(), other framebuffers...).
         *
         * Note that this function might not get called at all if the window
         * size doesn't change. You should configure the initial state of your
         * cameras, framebuffers etc. in application constructor rather than
         * relying on this function to be called. Size of the window can be
         * retrieved using @ref windowSize().
         */
        virtual void viewportEvent(ViewportEvent& event);

        /** @copydoc Sdl2Application::drawEvent() */
        virtual void drawEvent() = 0;

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

        /** @{ @name Keyboard handling */

        /** @copydoc Sdl2Application::keyPressEvent() */
        virtual void keyPressEvent(KeyEvent& event);

        /** @copydoc Sdl2Application::keyReleaseEvent() */
        virtual void keyReleaseEvent(KeyEvent& event);

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

        /** @{ @name Mouse handling */

        /** @copydoc Sdl2Application::mousePressEvent() */
        virtual void mousePressEvent(MouseEvent& event);

        /** @copydoc Sdl2Application::mouseReleaseEvent() */
        virtual void mouseReleaseEvent(MouseEvent& event);

        /** @copydoc Sdl2Application::mouseMoveEvent() */
        virtual void mouseMoveEvent(MouseMoveEvent& event);

        /* Since 1.8.17, the original short-hand group closing doesn't work
           anymore. FFS. */
        /**
         * @}
         */

    #ifdef DOXYGEN_GENERATING_OUTPUT
    private:
    #else
    protected:
    #endif
        explicit AbstractXApplication(Implementation::AbstractContextHandler<GLConfiguration, Display*, VisualID, Window>* contextHandler, const Arguments& arguments, const Configuration& configuration, const GLConfiguration& glConfiguration);

        explicit AbstractXApplication(Implementation::AbstractContextHandler<GLConfiguration, Display*, VisualID, Window>* contextHandler, const Arguments& arguments, NoCreateT);

    private:
        enum class Flag: unsigned int {
            Redraw = 1 << 0,
            Exit = 1 << 1
        };

        typedef Containers::EnumSet<Flag> Flags;
        CORRADE_ENUMSET_FRIEND_OPERATORS(Flags)

        Display* _display{};
        Window _window{};
        Atom _deleteWindow{};

        Containers::Pointer<Implementation::AbstractContextHandler<GLConfiguration, Display*, VisualID, Window>> _contextHandler;
        /* Has to be in an Optional because it gets explicitly destroyed before
           the GL context */
        Containers::Optional<Platform::GLContext> _context;
        int _exitCode = 0;

        /** @todo Get this from the created window */
        Vector2i _windowSize;

        Flags _flags;
};

/**
@brief OpenGL context configuration

Double-buffered OpenGL context.
@see @ref GlxApplication::GlxApplication(), @ref XEglApplication::XEglApplication(),
    @ref Configuration, @ref create(), @ref tryCreate()
@todo GLX_ARB_create_context_robustness/EGL_EXT_create_context_robustness
*/
class AbstractXApplication::GLConfiguration: public GL::Context::Configuration {
    public:
        /**
         * @brief Context flag
         *
         * Includes also everything from @ref GL::Context::Configuration::Flag
         * except for @relativeref{GL::Context::Configuration,Flag::Windowless},
         * which is not meant to be enabled for windowed apps.
         * @see @ref Flags, @ref setFlags(), @ref GL::Context::Flag
         */
        enum class Flag: UnsignedLong {
            /**
             * @copydoc GL::Context::Configuration::Flag::QuietLog
             * @m_since_latest
             */
            QuietLog = UnsignedLong(GL::Context::Configuration::Flag::QuietLog),

            /**
             * @copydoc GL::Context::Configuration::Flag::VerboseLog
             * @m_since_latest
             */
            VerboseLog = UnsignedLong(GL::Context::Configuration::Flag::VerboseLog),

            /**
             * @copydoc GL::Context::Configuration::Flag::GpuValidation
             * @m_since_latest
             */
            GpuValidation = UnsignedLong(GL::Context::Configuration::Flag::GpuValidation),

            /**
             * @copydoc GL::Context::Configuration::Flag::GpuValidationNoError
             * @m_since_latest
             */
            GpuValidationNoError = UnsignedLong(GL::Context::Configuration::Flag::GpuValidationNoError)
        };

        /**
         * @brief Context flags
         *
         * @see @ref setFlags(), @ref GL::Context::Flags
         */
        typedef Containers::EnumSet<Flag> Flags;

        explicit GLConfiguration();
        ~GLConfiguration();

        /** @brief Context flags */
        Flags flags() const {
            return Flag(UnsignedLong(GL::Context::Configuration::flags()));
        }

        /**
         * @brief Set context flags
         * @return Reference to self (for method chaining)
         *
         * Default is no flag. To avoid clearing default flags by accident,
         * prefer to use @ref addFlags() and @ref clearFlags() instead.
         * @see @ref GL::Context::flags()
         */
        GLConfiguration& setFlags(Flags flags) {
            GL::Context::Configuration::setFlags(GL::Context::Configuration::Flag(UnsignedLong(flags)));
            return *this;
        }

        /**
         * @brief Add context flags
         * @return Reference to self (for method chaining)
         *
         * Unlike @ref setFlags(), ORs the flags with existing instead of
         * replacing them. Useful for preserving the defaults.
         * @see @ref clearFlags()
         */
        GLConfiguration& addFlags(Flags flags) {
            GL::Context::Configuration::addFlags(GL::Context::Configuration::Flag(UnsignedLong(flags)));
            return *this;
        }

        /**
         * @brief Clear context flags
         * @return Reference to self (for method chaining)
         *
         * Unlike @ref setFlags(), ANDs the inverse of @p flags with existing
         * instead of replacing them. Useful for removing default flags.
         * @see @ref addFlags()
         */
        GLConfiguration& clearFlags(Flags flags) {
            GL::Context::Configuration::clearFlags(GL::Context::Configuration::Flag(UnsignedLong(flags)));
            return *this;
        }

        /** @copydoc Sdl2Application::GLConfiguration::version() */
        GL::Version version() const { return _version; }

        /** @copydoc Sdl2Application::GLConfiguration::setVersion() */
        GLConfiguration& setVersion(GL::Version version) {
            _version = version;
            return *this;
        }

        /* Overloads to remove WTF-factor from method chaining order */
        #ifndef DOXYGEN_GENERATING_OUTPUT
        MAGNUM_GL_CONTEXT_CONFIGURATION_SUBCLASS_IMPLEMENTATION(GLConfiguration)
        #endif

    private:
        GL::Version _version;
};

/**
@brief Configuration

@see @ref GlxApplication::GlxApplication(), @ref XEglApplication::XEglApplication(),
    @ref GLConfiguration, @ref create(), @ref tryCreate()
*/
class AbstractXApplication::Configuration {
    public:
        /*implicit*/ Configuration();
        ~Configuration();

        /**
         * @brief Window title
         *
         * The returned view is always
         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
         * is valid until the next call to @ref setTitle().
         */
        Containers::StringView title() const { return _title; }

        /**
         * @brief Set window title
         * @return Reference to self (for method chaining)
         *
         * Default is @cpp "Magnum X Application" @ce.
         */
        Configuration& setTitle(Containers::StringView title) {
            _title = Containers::String::nullTerminatedGlobalView(title);
            return *this;
        }

        /** @copydoc Sdl2Application::Configuration::size() */
        Vector2i size() const { return _size; }

        /**
         * @brief Set window size
         * @return Reference to self (for method chaining)
         *
         * Default is @cpp {800, 600} @ce.
         */
        Configuration& setSize(const Vector2i& size) {
            _size = size;
            return *this;
        }

    private:
        Containers::String _title;
        Vector2i _size;
};

/**
@brief Viewport event

@see @ref viewportEvent()
*/
class AbstractXApplication::ViewportEvent {
    public:
        /** @brief Copying is not allowed */
        ViewportEvent(const ViewportEvent&) = delete;

        /** @brief Moving is not allowed */
        ViewportEvent(ViewportEvent&&) = delete;

        /** @brief Copying is not allowed */
        ViewportEvent& operator=(const ViewportEvent&) = delete;

        /** @brief Moving is not allowed */
        ViewportEvent& operator=(ViewportEvent&&) = delete;

        /**
         * @brief Window size
         *
         * Same as @ref framebufferSize().
         * @see @ref AbstractXApplication::windowSize()
         */
        Vector2i windowSize() const { return _size; }

        /**
         * @brief Framebuffer size
         *
         * Same as @ref windowSize().
         * @see @ref AbstractXApplication::framebufferSize()
         */
        Vector2i framebufferSize() const { return _size; }

    private:
        friend AbstractXApplication;

        explicit ViewportEvent(const Vector2i& size): _size{size} {}

        const Vector2i _size;
};

/**
@brief Base for input events

@see @ref KeyEvent, @ref MouseEvent, @ref MouseMoveEvent, @ref keyPressEvent(),
    @ref keyReleaseEvent(), @ref mousePressEvent(), @ref mouseReleaseEvent(),
    @ref mouseMoveEvent()
*/
class AbstractXApplication::InputEvent {
    public:
        /**
         * @brief Modifier
         *
         * @see @ref Modifiers, @ref modifiers()
         */
        enum class Modifier: unsigned int {
            Shift = ShiftMask,          /**< Shift */
            Ctrl = ControlMask,         /**< Ctrl */
            Alt = Mod1Mask,             /**< Alt */
            AltGr = Mod5Mask,           /**< AltGr */
            CapsLock = LockMask,        /**< Caps lock */
            NumLock = Mod2Mask          /**< Num lock */
        };

        /**
         * @brief Set of modifiers
         *
         * @see @ref modifiers()
         */
        typedef Containers::EnumSet<Modifier> Modifiers;

        /**
         * @brief Mouse button
         *
         * @see @ref Buttons, @ref buttons()
         */
        enum class Button: unsigned int {
            Left = Button1Mask,     /**< Left button */
            Middle = Button2Mask,   /**< Middle button */
            Right = Button3Mask     /**< Right button */
        };

        /**
         * @brief Set of mouse buttons
         *
         * @see @ref buttons()
         */
        typedef Containers::EnumSet<Button> Buttons;

        /** @brief Copying is not allowed */
        InputEvent(const InputEvent&) = delete;

        /** @brief Moving is not allowed */
        InputEvent(InputEvent&&) = delete;

        /** @brief Copying is not allowed */
        InputEvent& operator=(const InputEvent&) = delete;

        /** @brief Moving is not allowed */
        InputEvent& operator=(InputEvent&&) = delete;

        /** @copydoc Sdl2Application::InputEvent::setAccepted() */
        void setAccepted(bool accepted = true) { _accepted = accepted; }

        /** @copydoc Sdl2Application::InputEvent::isAccepted() */
        bool isAccepted() const { return _accepted; }

        /** @brief Modifiers */
        Modifiers modifiers() const { return _modifiers; }

        /** @brief Mouse buttons */
        Buttons buttons() const { return Button(static_cast<unsigned int>(_modifiers)); }

    #ifndef DOXYGEN_GENERATING_OUTPUT
    protected:
        explicit InputEvent(Modifiers modifiers): _modifiers(modifiers), _accepted(false) {}

        ~InputEvent() = default;
    #endif

    private:
        Modifiers _modifiers;
        bool _accepted;
};

CORRADE_ENUMSET_OPERATORS(AbstractXApplication::InputEvent::Modifiers)
CORRADE_ENUMSET_OPERATORS(AbstractXApplication::InputEvent::Buttons)

/**
@brief Key event

@see @ref keyPressEvent(), @ref keyReleaseEvent()
*/
class AbstractXApplication::KeyEvent: public AbstractXApplication::InputEvent {
    friend AbstractXApplication;

    public:
        /**
         * @brief Key
         *
         * @see @ref key()
         */
        enum class Key: KeySym {
            Enter = XK_Return,          /**< Enter */
            Esc = XK_Escape,            /**< Escape */

            Up = XK_Up,                 /**< Up arrow */
            Down = XK_Down,             /**< Down arrow */
            Left = XK_Left,             /**< Left arrow */
            Right = XK_Right,           /**< Right arrow */
            F1 = XK_F1,                 /**< F1 */
            F2 = XK_F2,                 /**< F2 */
            F3 = XK_F3,                 /**< F3 */
            F4 = XK_F4,                 /**< F4 */
            F5 = XK_F5,                 /**< F5 */
            F6 = XK_F6,                 /**< F6 */
            F7 = XK_F7,                 /**< F7 */
            F8 = XK_F8,                 /**< F8 */
            F9 = XK_F9,                 /**< F9 */
            F10 = XK_F10,               /**< F10 */
            F11 = XK_F11,               /**< F11 */
            F12 = XK_F12,               /**< F12 */
            Home = XK_Home,             /**< Home */
            End = XK_End,               /**< End */
            PageUp = XK_Page_Up,        /**< Page up */
            PageDown = XK_Page_Down,    /**< Page down */

            Space = XK_space,           /**< Space */
            Comma = XK_comma,           /**< Comma */
            Period = XK_period,         /**< Period */
            Minus = XK_minus,           /**< Minus */
            Plus = XK_plus,             /**< Plus */
            Slash = XK_slash,           /**< Slash */
            Percent = XK_percent,       /**< Percent */
            Equal = XK_equal,           /**< Equal */

            Zero = XK_0,                /**< Zero */
            One = XK_1,                 /**< One */
            Two = XK_2,                 /**< Two */
            Three = XK_3,               /**< Three */
            Four = XK_4,                /**< Four */
            Five = XK_5,                /**< Five */
            Six = XK_6,                 /**< Six */
            Seven = XK_7,               /**< Seven */
            Eight = XK_8,               /**< Eight */
            Nine = XK_9,                /**< Nine */

            A = XK_a,                   /**< Small letter A */
            B = XK_b,                   /**< Small letter B */
            C = XK_c,                   /**< Small letter C */
            D = XK_d,                   /**< Small letter D */
            E = XK_e,                   /**< Small letter E */
            F = XK_f,                   /**< Small letter F */
            G = XK_g,                   /**< Small letter G */
            H = XK_h,                   /**< Small letter H */
            I = XK_i,                   /**< Small letter I */
            J = XK_j,                   /**< Small letter J */
            K = XK_k,                   /**< Small letter K */
            L = XK_l,                   /**< Small letter L */
            M = XK_m,                   /**< Small letter M */
            N = XK_n,                   /**< Small letter N */
            O = XK_o,                   /**< Small letter O */
            P = XK_p,                   /**< Small letter P */
            Q = XK_q,                   /**< Small letter Q */
            R = XK_r,                   /**< Small letter R */
            S = XK_s,                   /**< Small letter S */
            T = XK_t,                   /**< Small letter T */
            U = XK_u,                   /**< Small letter U */
            V = XK_v,                   /**< Small letter V */
            W = XK_w,                   /**< Small letter W */
            X = XK_x,                   /**< Small letter X */
            Y = XK_y,                   /**< Small letter Y */
            Z = XK_z                    /**< Small letter Z */
        };

        /** @brief Key */
        Key key() const { return _key; }

        /** @brief Position */
        Vector2i position() const { return _position; }

    private:
        explicit KeyEvent(Key key, Modifiers modifiers, const Vector2i& position): InputEvent(modifiers), _key(key), _position(position) {}

        const Key _key;
        const Vector2i _position;
};

/**
@brief Mouse event

@see @ref MouseMoveEvent, @ref mousePressEvent(), @ref mouseReleaseEvent()
*/
class AbstractXApplication::MouseEvent: public AbstractXApplication::InputEvent {
    friend AbstractXApplication;

    public:
        /**
         * @brief Mouse button
         *
         * @see @ref button()
         */
        enum class Button: unsigned int {
            Left      = 1 /*Button1*/,  /**< Left button */
            Middle    = 2 /*Button2*/,  /**< Middle button */
            Right     = 3 /*Button3*/,  /**< Right button */
            WheelUp   = 4 /*Button4*/,  /**< Wheel up */
            WheelDown = 5 /*Button5*/   /**< Wheel down */
        };

        /** @brief Button */
        Button button() const { return _button; }

        /** @brief Position */
        Vector2i position() const { return _position; }

    private:
        explicit MouseEvent(Button button, Modifiers modifiers, const Vector2i& position): InputEvent(modifiers), _button(button), _position(position) {}

        const Button _button;
        const Vector2i _position;
};

/**
@brief Mouse move event

@see @ref MouseEvent, @ref mouseMoveEvent()
*/
class AbstractXApplication::MouseMoveEvent: public AbstractXApplication::InputEvent {
    friend AbstractXApplication;

    public:
        /** @brief Position */
        Vector2i position() const { return _position; }

    private:
        explicit MouseMoveEvent(Modifiers modifiers, const Vector2i& position): InputEvent(modifiers), _position(position) {}

        const Vector2i _position;
};

}}
#else
#error this header is available only in the OpenGL build
#endif

#endif