COpenGLScene.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/opengl/COpenGLViewport.h>
#include <mrpt/opengl/CRenderizable.h>

/** The namespace for 3D scene representation and rendering. See also the <a
 * href="mrpt-opengl.html" > summary page</a> of the mrpt-opengl library for
 * more info and thumbnails of many of the render primitive.
 */
namespace mrpt::opengl
{
/** This class allows the user to create, load, save, and render 3D scenes using
 * OpenGL primitives.
 *  The class can be understood as a program to be run over OpenGL, containing
 * a sequence of viewport definitions,
 *   rendering primitives, etc...
 *
 *  It can contain from 1 up to any number of <b>Viewports</b>, each one
 *   associated a set of OpenGL objects and, optionally, a preferred camera
 * position. Both orthogonal (2D/3D) and projection
 *   camera models can be used for each viewport independently, greatly
 * increasing the possibilities of rendered scenes.
 *
 *  An object of COpenGLScene always contains at least one viewport
 * (utils::COpenGLViewport), named "main". Optionally, any
 *   number of other viewports may exist. Viewports are referenced by their
 * names, case-sensitive strings. Each viewport contains
 *   a different 3D scene (i.e. they render different objects), though a
 * mechanism exist to share the same 3D scene by a number of
 *   viewports so memory is not wasted replicating the same objects (see
 * COpenGLViewport::setCloneView ).
 *
 *  The main rendering method, COpenGLScene::render(), assumes a viewport has
 * been set-up for the entire target window. That
 *   method will internally make the required calls to opengl for creating the
 * additional viewports. Note that only the depth
 *   buffer is cleared by default for each (non-main) viewport, to allow
 * transparencies. This can be disabled by the approppriate
 *   member in COpenGLViewport.
 *
 *   An object COpenGLScene can be saved to a ".3Dscene" file using
 * CFileOutputStream, for posterior visualization from
 *    the standalone application <a
 * href="http://www.mrpt.org/Application:SceneViewer" >SceneViewer</a>.
 *    It can be also displayed in real-time using gui::CDisplayWindow3D.
 * \ingroup mrpt_opengl_grp
 */
class COpenGLScene : public mrpt::serialization::CSerializable
{
    DEFINE_SERIALIZABLE(COpenGLScene, mrpt::opengl)
   public:
    using TListViewports = std::vector<COpenGLViewport::Ptr>;

    COpenGLScene();
    ~COpenGLScene() override;
    COpenGLScene& operator=(const COpenGLScene& obj);
    COpenGLScene(const COpenGLScene& obj);

    /**
     * Inserts a set of objects into the scene, in the given viewport ("main"
     * by default). Any iterable object will be accepted.
     * \sa createViewport,getViewport
     */
    template <class T>
    inline void insertCollection(
        const T& objs, const std::string& vpn = std::string("main"))
    {
        insert(objs.begin(), objs.end(), vpn);
    }
    /** Insert a new object into the scene, in the given viewport (by default,
     * into the "main" viewport).
     *  The viewport must be created previously, an exception will be raised if
     * the given name does not correspond to
     *   an existing viewport.
     * \sa createViewport, getViewport
     */
    void insert(
        const CRenderizable::Ptr& newObject,
        const std::string& viewportName = std::string("main"));

    /**
     * Inserts a set of objects into the scene, in the given viewport ("main"
     * by default).
     * \sa createViewport,getViewport
     */
    template <class T_it>
    inline void insert(
        const T_it& begin, const T_it& end,
        const std::string& vpn = std::string("main"))
    {
        for (T_it it = begin; it != end; it++) insert(*it, vpn);
    }

    /**Creates a new viewport, adding it to the scene and returning a pointer to
     * the new object.
     *  Names (case-sensitive) cannot be duplicated: if the name provided
     * coincides with an already existing viewport, a pointer to the existing
     * object will be returned.
     *  The first, default viewport, is named "main".
     */
    COpenGLViewport::Ptr createViewport(const std::string& viewportName);

    /** Returns the viewport with the given name, or nullptr if it does not
     * exist; note that the default viewport is named "main" and initially
     * occupies the entire rendering area.
     */
    COpenGLViewport::Ptr getViewport(
        const std::string& viewportName = std::string("main")) const;

    const TListViewports& viewports() const { return m_viewports; }

    /** Render this scene */
    void render() const;

    size_t viewportsCount() const { return m_viewports.size(); }
    /** Clear the list of objects and viewports in the scene, deleting objects'
     * memory, and leaving just the default viewport with the default values.
     */
    void clear(bool createMainViewport = true);

    /** If disabled (default), the SceneViewer application will ignore the
     * camera of the "main" viewport and keep the viewport selected by the user
     * by hand; otherwise, the camera in the "main" viewport prevails.
     * \sa followCamera
     */
    void enableFollowCamera(bool enabled) { m_followCamera = enabled; }
    /** Return the value of "followCamera"
     * \sa enableFollowCamera
     */
    bool followCamera() const { return m_followCamera; }
    /** Returns the first object with a given name, or nullptr (an empty smart
     * pointer) if not found.
     */
    CRenderizable::Ptr getByName(
        const std::string& str,
        const std::string& viewportName = std::string("main"));

    /** Returns the i'th object of a given class (or of a descendant class), or
      nullptr (an empty smart pointer) if not found.
      *  Example:
      * \code
           CSphere::Ptr obs = myscene.getByClass<CSphere>();
      * \endcode
      * By default (ith=0), the first observation is returned.
      */
    template <typename T>
    typename T::Ptr getByClass(size_t ith = 0) const
    {
        MRPT_START
        for (const auto& m_viewport : m_viewports)
        {
            typename T::Ptr o = m_viewport->getByClass<T>(ith);
            if (o) return o;
        }
        return typename T::Ptr();  // Not found: return empty smart pointer
        MRPT_END
    }

    /** Removes the given object from the scene (it also deletes the object to
     * free its memory).
     */
    void removeObject(
        const CRenderizable::Ptr& obj,
        const std::string& viewportName = std::string("main"));

    /** Initializes all textures in the scene (See
     * opengl::CTexturedPlane::initializeTextures)
     */
    void initializeTextures();

    /** Retrieves a list of all objects in text form.
     */
    void dumpListOfObjects(std::vector<std::string>& lst);

    /** Saves the scene to a 3Dscene file, loadable by the application
     * SceneViewer3D
     * \sa loadFromFile
     * \return false on any error.
     */
    bool saveToFile(const std::string& fil) const;

    /** Loads the scene from a 3Dscene file, the format used by the application
     * SceneViewer3D.
     * \sa saveToFile
     * \return false on any error.
     */
    bool loadFromFile(const std::string& fil);

    /** Traces a ray
     */
    bool traceRay(const mrpt::poses::CPose3D& o, double& dist) const;

    /** Evaluates the bounding box of the scene in the given viewport (default:
     * "main"). */
    void getBoundingBox(
        mrpt::math::TPoint3D& bb_min, mrpt::math::TPoint3D& bb_max,
        const std::string& vpn = std::string("main")) const;

    /** Recursive depth-first visit all objects in all viewports of the scene,
     * calling the user-supplied function
     *  The passed function must accept only one argument of type "const
     * mrpt::opengl::CRenderizable::Ptr &"
     */
    template <typename FUNCTOR>
    void visitAllObjects(FUNCTOR functor) const
    {
        MRPT_START
        for (const auto& m_viewport : m_viewports)
            for (auto itO = m_viewport->begin(); itO != m_viewport->end();
                 ++itO)
                internal_visitAllObjects(functor, *itO);
        MRPT_END
    }

    /** Ensure all shaders are unloaded in all viewports */
    void unloadShaders();

    /** Ensure all OpenGL buffers are destroyed. */
    void freeOpenGLResources();

   protected:
    bool m_followCamera{false};

    /** The list of viewports, indexed by name. */
    TListViewports m_viewports;

    template <typename FUNCTOR>
    static void internal_visitAllObjects(
        FUNCTOR functor, const CRenderizable::Ptr& o)
    {
        functor(o);
        if (IS_CLASS(*o, CSetOfObjects))
        {
            CSetOfObjects::Ptr obj =
                std::dynamic_pointer_cast<CSetOfObjects>(o);
            for (auto it = obj->begin(); it != obj->end(); ++it)
                internal_visitAllObjects(functor, *it);
        }
    }
};

/** Inserts an openGL object into a scene. Allows call chaining. \sa
 * mrpt::opengl::COpenGLScene::insert  */
inline COpenGLScene::Ptr& operator<<(
    COpenGLScene::Ptr& s, const CRenderizable::Ptr& r)
{
    s->insert(r);
    return s;
}
/**Inserts any iterable collection of openGL objects into a scene, allowing call
 * chaining.  \sa mrpt::opengl::COpenGLScene::insert */
template <class T>
inline COpenGLScene::Ptr& operator<<(
    COpenGLScene::Ptr& s, const std::vector<T>& v)
{
    s->insert(v.begin(), v.end());
    return s;
}
}  // namespace mrpt::opengl