magnum/src/Platform/GlutApplication.h

#ifndef Magnum_Platform_GlutApplication_h
#define Magnum_Platform_GlutApplication_h
/*
    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>

    This file is part of Magnum.

    Magnum is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License version 3
    only, as published by the Free Software Foundation.

    Magnum is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU Lesser General Public License version 3 for more details.
*/

/** @file
 * @brief Class Magnum::Platform::GlutApplication
 */

#include <string>

#include "Math/Vector2.h"
#include "Magnum.h"

#include <GL/freeglut.h>

#include "magnumCompatibility.h"

namespace Magnum {

class Context;

namespace Platform {

/** @nosubgrouping
@brief GLUT application

Supports keyboard handling for limited subset of keys, mouse handling with
support for changing cursor and mouse tracking and warping.

@section GlutApplication-usage Usage

You need to implement at least drawEvent() and viewportEvent() to be able to
draw on the screen. The subclass can be then used directly in `main()` - see
convenience macro MAGNUM_GLUTAPPLICATION_MAIN().
@code
class MyApplication: public Magnum::Platform::GlutApplication {
    // implement required methods...
};
MAGNUM_GLUTAPPLICATION_MAIN(MyApplication)
@endcode
*/
class GlutApplication {
    public:
        /**
         * @brief Constructor
         * @param argc      Count of arguments of `main()` function
         * @param argv      Arguments of `main()` function
         * @param title     Window title
         * @param size      Window size
         *
         * Creates double-buffered RGBA window with depth and stencil buffers.
         */
        GlutApplication(int& argc, char** argv, const std::string& title = "Magnum GLUT application", const Math::Vector2<GLsizei>& size = Math::Vector2<GLsizei>(800, 600));

        virtual ~GlutApplication();

        /**
         * @brief Execute main loop
         * @return Value for returning from `main()`.
         */
        inline int exec() {
            glutMainLoop();
            return 0;
        }

        /** @{ @name Drawing functions */

    protected:
        /**
         * @brief Viewport event
         *
         * Called when viewport size changes. You should pass the new size to
         * Framebuffer::setViewport() (and SceneGraph::AbstractCamera::setViewport(),
         * if using scene graph).
         */
        virtual void viewportEvent(const Math::Vector2<GLsizei>& size) = 0;

        /**
         * @brief Draw event
         *
         * Here implement your drawing functions, such as calling
         * SceneGraph::AbstractCamera::draw(). After drawing is finished, call
         * swapBuffers(). If you want to draw immediately again, call also
         * redraw().
         */
        virtual void drawEvent() = 0;

        /**
         * @brief Swap buffers
         *
         * Paints currently rendered framebuffer on screen.
         */
        inline void swapBuffers() {
            glutSwapBuffers();
        }

        /**
         * @brief Redraw immediately
         *
         * Marks the window for redrawing, resulting in call to drawEvent()
         * in the next iteration.
         */
        virtual inline void redraw() {
            glutPostRedisplay();
        }

        /*@}*/

        /** @{ @name Keyboard handling */

    public:
        /**
         * @brief Key
         *
         * @see keyPressEvent()
         */
        enum class Key: int {
            Up = GLUT_KEY_UP,               /**< Up arrow */
            Down = GLUT_KEY_DOWN,           /**< Down arrow */
            Left = GLUT_KEY_LEFT,           /**< Left arrow */
            Right = GLUT_KEY_RIGHT,         /**< Right arrow */
            F1 = GLUT_KEY_F1,               /**< F1 */
            F2 = GLUT_KEY_F2,               /**< F2 */
            F3 = GLUT_KEY_F3,               /**< F3 */
            F4 = GLUT_KEY_F4,               /**< F4 */
            F5 = GLUT_KEY_F5,               /**< F5 */
            F6 = GLUT_KEY_F6,               /**< F6 */
            F7 = GLUT_KEY_F7,               /**< F7 */
            F8 = GLUT_KEY_F8,               /**< F8 */
            F9 = GLUT_KEY_F9,               /**< F9 */
            F10 = GLUT_KEY_F10,             /**< F10 */
            F11 = GLUT_KEY_F11,             /**< F11 */
            F12 = GLUT_KEY_F12,             /**< F12 */
            Home = GLUT_KEY_HOME,           /**< Home */
            End = GLUT_KEY_END,             /**< End */
            PageUp = GLUT_KEY_PAGE_UP,      /**< Page up */
            PageDown = GLUT_KEY_PAGE_DOWN   /**< Page down */
        };

    protected:
        /**
         * @brief Key press event
         * @param key       Key pressed
         * @param position  Cursor position
         *
         * Called when an key is pressed. Default implementation does nothing.
         */
        virtual void keyPressEvent(Key key, const Math::Vector2<int>& position);

        /*@}*/

        /** @{ @name Mouse handling */

    public:
        /**
         * @brief Mouse button
         *
         * @see mousePressEvent(), mouseReleaseEvent()
         */
        enum class MouseButton: int {
            Left = GLUT_LEFT_BUTTON,        /**< Left button */
            Middle = GLUT_MIDDLE_BUTTON,    /**< Middle button */
            Right = GLUT_RIGHT_BUTTON,      /**< Right button */
            WheelUp = 3,                    /**< Wheel up */
            WheelDown = 4                   /**< Wheel down */
        };

        /**
         * @brief Mouse cursor
         *
         * @see setMouseCursor()
         */
        enum class MouseCursor: int {
            Default = GLUT_CURSOR_INHERIT,  /**< Default cursor provided by parent window */
            None = GLUT_CURSOR_NONE         /**< No cursor */
        };

        /**
         * @brief Enable or disable mouse tracking
         *
         * When mouse tracking is enabled, mouseMoveEvent() is called even
         * when no button is pressed. Mouse tracking is disabled by default.
         */
        inline void setMouseTracking(bool enabled) {
            glutPassiveMotionFunc(enabled ? staticMouseMotionEvent : nullptr);
        }

        /** @brief Set mouse cursor */
        inline void setMouseCursor(MouseCursor cursor) {
            glutSetCursor(static_cast<int>(cursor));
        }

        /** @brief Warp mouse cursor to given coordinates */
        inline void warpMouseCursor(const Math::Vector2<GLsizei>& position) {
            glutWarpPointer(position.x(), position.y());
        }

    protected:
        /**
         * @brief Mouse press event
         *
         * Called when mouse button is pressed. Default implementation does
         * nothing.
         */
        virtual void mousePressEvent(MouseButton button, const Math::Vector2<int>& position);

        /**
         * @brief Mouse release event
         *
         * Called when mouse button is released. Default implementation does
         * nothing.
         */
        virtual void mouseReleaseEvent(MouseButton button, const Math::Vector2<int>& position);

        /**
         * @brief Mouse motion event
         *
         * Called when any mouse button is pressed and mouse is moved. Default
         * implementation does nothing.
         * @see setMouseTracking()
         */
        virtual void mouseMotionEvent(const Math::Vector2<int>& position);

        /*@}*/

    private:
        inline static void staticViewportEvent(int x, int y) {
            instance->viewportEvent({x, y});
        }

        inline static void staticKeyEvent(int key, int x, int y) {
            instance->keyPressEvent(static_cast<Key>(key), {x, y});
        }

        inline static void staticMouseEvent(int button, int state, int x, int y) {
            if(state == GLUT_DOWN)
                instance->mousePressEvent(static_cast<MouseButton>(button), {x, y});
            else
                instance->mouseReleaseEvent(static_cast<MouseButton>(button), {x, y});
        }

        inline static void staticMouseMotionEvent(int x, int y) {
            instance->mouseMotionEvent({x, y});
        }

        inline static void staticDrawEvent() {
            instance->drawEvent();
        }

        static GlutApplication* instance;

        Context* c;
};

/** @hideinitializer
@param className Class name

Can be used as equivalent to the following code to achieve better portability,
see @ref portability-applications for more information.
@code
int main(int argc, char** argv) {
    className app(argc, argv);
    return app.exec();
}
@endcode
When no other application header is included this macro is also aliased to
`MAGNUM_APPLICATION_MAIN()`.
*/
#define MAGNUM_GLUTAPPLICATION_MAIN(className)                              \
    int main(int argc, char** argv) {                                       \
        className app(argc, argv);                                          \
        return app.exec();                                                  \
    }

#ifndef DOXYGEN_GENERATING_OUTPUT
#ifndef MAGNUM_APPLICATION_MAIN
#define MAGNUM_APPLICATION_MAIN(className) MAGNUM_GLUTAPPLICATION_MAIN(className)
#else
#undef MAGNUM_APPLICATION_MAIN
#endif
#endif

/* Implementations for inline functions with unused parameters */
inline void GlutApplication::keyPressEvent(Key, const Math::Vector2<int>&) {}
inline void GlutApplication::mousePressEvent(MouseButton, const Math::Vector2<int>&) {}
inline void GlutApplication::mouseReleaseEvent(MouseButton, const Math::Vector2<int>&) {}
inline void GlutApplication::mouseMotionEvent(const Math::Vector2<int>&) {}

}}

#endif