COpenGLViewport.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/core/safe_pointers.h>
#include <mrpt/img/CImage.h>
#include <mrpt/opengl/CCamera.h>
#include <mrpt/opengl/CSetOfLines.h>
#include <mrpt/opengl/CSetOfObjects.h>
#include <mrpt/opengl/CTextMessageCapable.h>
#include <mrpt/opengl/CTexturedPlane.h>
#include <mrpt/opengl/Shader.h>
#include <mrpt/opengl/TLightParameters.h>
#include <mrpt/opengl/TRenderMatrices.h>
#include <mrpt/opengl/opengl_frwds.h>
#include <mrpt/serialization/CSerializable.h>
#include <mrpt/system/CObservable.h>
#include <mrpt/system/mrptEvent.h>
#include <map>

namespace mrpt::img
{
class CImage;
}
namespace mrpt::opengl
{
/** A viewport within a COpenGLScene, containing a set of OpenGL objects to
 *render.
 *   This class has protected constuctor, thus it cannot be created by users.
 *Use COpenGLScene::createViewport instead.
 *  A viewport has these "operation modes":
 *      - Normal (default): It renders the contained objects.
 *      - Cloned: It clones the objects from another viewport. See \a
 *setCloneView()
 *      - Image mode: It renders an image (e.g. from a video stream) efficiently
 *using a textued quad. See \a setImageView().
 *
 * In any case, the viewport can be resized to only fit a part of the entire
 *parent viewport.
 *  There will be always at least one viewport in a COpenGLScene named "main".
 *
 * This class can be observed (see mrpt::system::CObserver) for the following
 *events (see mrpt::system::mrptEvent):
 *   - mrpt::opengl::mrptEventGLPreRender
 *   - mrpt::opengl::mrptEventGLPostRender
 *
 * Two directional light sources at infinity are created by default, with
 *directions (-1,-1,-1) and (1,2,1), respectively.
 *
 * Lighting parameters are accessible via lightParameters().
 *
 *  Refer to mrpt::opengl::COpenGLScene for further details.
 * \ingroup mrpt_opengl_grp
 */
class COpenGLViewport : public mrpt::serialization::CSerializable,
                        public mrpt::system::CObservable,
                        public mrpt::opengl::CTextMessageCapable
{
    DEFINE_SERIALIZABLE(COpenGLViewport, mrpt::opengl)
    friend class COpenGLScene;

   public:
    /** @name Set the viewport "modes"
        @{ */

    /** Set this viewport as a clone of some other viewport, given its name - as
     * a side effect, current list of internal OpenGL objects is cleared.
     *  By default, only the objects are cloned, not the camera. See
     * \sa resetCloneView
     */
    void setCloneView(const std::string& clonedViewport);

    /** Set this viewport into "image view"-mode, where an image is efficiently
     * drawn (fitting the viewport area) using an OpenGL textured quad.
     *  Call this method with the new image to update the displayed image (but
     * recall to first lock the parent openglscene's critical section, then do
     * the update, then release the lock, and then issue a window repaint).
     *  Internally, the texture is drawn using a mrpt::opengl::CTexturedPlane
     *  The viewport can be reverted to behave like a normal viewport by
     * calling setNormalMode()
     */
    void setImageView(const mrpt::img::CImage& img);

    /** Just like \a setImageView but moves the internal image memory instead of
     * making a copy, so it's faster but empties the input image.
     * \sa setImageView
     */
    void setImageView(mrpt::img::CImage&& img);

    /** Reset the viewport to normal mode: rendering its own objects.
     * \sa setCloneView, setNormalMode
     */
    inline void resetCloneView() { setNormalMode(); }
    /** If set to true, and setCloneView() has been called, this viewport will
     * be rendered using the camera of the cloned viewport.
     */
    inline void setCloneCamera(bool enable) { m_isClonedCamera = enable; }
    /** Resets the viewport to a normal 3D viewport \sa setCloneView,
     * setImageView */
    void setNormalMode();

    /** @} */
    // end of Set the "viewport mode"

    /** @name OpenGL global settings that affect rendering all objects in the
       scene/viewport
        @{ */

    /** Sets glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST) is enabled, or GL_FASTEST
     * otherwise. */
    void enablePolygonNicest(bool enable = true)
    {
        m_OpenGL_enablePolygonNicest = enable;
    }
    bool isPolygonNicestEnabled() const { return m_OpenGL_enablePolygonNicest; }

    const TLightParameters& lightParameters() const { return m_lights; }
    TLightParameters& lightParameters() { return m_lights; }

    /** @} */

    /** @name Change or read viewport properties (except "viewport modes")
        @{ */

    /** Returns the name of the viewport */
    inline std::string getName() { return m_name; }
    /** Change the viewport position and dimension on the rendering window.
     *  X & Y coordinates here can have two interpretations:
     *    - If in the range [0,1], they are factors with respect to the actual
     *window sizes (i.e. width=1 means the entire width of the rendering
     *window).
     *    - If >1, they are interpreted as pixels.
     *
     *  width & height can be interpreted as:
     *      - If >1, they are the size of the viewport in that dimension, in
     *pixels.
     *      - If in [0,1], they are the size of the viewport in that dimension,
     *in
     *a factor of the width/height.
     *      - If in [-1,0[, the size is computed such as the right/top border
     *ends
     *up in the given coordinate, interpreted as a factor (e.g. -1: up to the
     *end of the viewport, -0.5: up to the middle of it).
     *      - If <-1 the size is computed such as the right/top border ends up
     *in
     *the given absolute coordinate (e.g. -200: up to the row/column 200px).
     *
     * \note (x,y) specify the lower left corner of the viewport rectangle.
     * \sa getViewportPosition
     */
    void setViewportPosition(
        const double x, const double y, const double width,
        const double height);

    /** Get the current viewport position and dimension on the rendering window.
     *  X & Y coordinates here can have two interpretations:
     *    - If in the range [0,1], they are factors with respect to the actual
     * window sizes (i.e. width=1 means the entire width of the rendering
     * window).
     *    - If >1, they are interpreted as pixels.
     * \note (x,y) specify the lower left corner of the viewport rectangle.
     * \sa setViewportPosition
     */
    void getViewportPosition(
        double& x, double& y, double& width, double& height);

    /** Set the min/max clip depth distances of the rendering frustum (default:
     * 0.1 - 10000)
     * \sa getViewportClipDistances
     */
    void setViewportClipDistances(const float clip_min, const float clip_max);

    /** Get the current min/max clip depth distances of the rendering frustum
     * (default: 0.1 - 10000)
     * \sa setViewportClipDistances
     */
    void getViewportClipDistances(float& clip_min, float& clip_max) const;

    /** Set the border size ("frame") of the viewport (default=0) */
    inline void setBorderSize(unsigned int lineWidth)
    {
        m_borderWidth = lineWidth;
    }
    inline unsigned int getBorderSize() const { return m_borderWidth; }

    void setBorderColor(const mrpt::img::TColor& c) { m_borderColor = c; }
    const mrpt::img::TColor& getBorderColor() const { return m_borderColor; }

    /** Return whether the viewport will be rendered transparent over previous
     * viewports.
     */
    inline bool isTransparent() { return m_isTransparent; }
    /** Set the transparency, that is, whether the viewport will be rendered
     * transparent over previous viewports (default=false).
     */
    inline void setTransparent(bool trans) { m_isTransparent = trans; }
    /** Set a background color different from that of the parent GUI window */
    inline void setCustomBackgroundColor(const mrpt::img::TColorf& color)
    {
        m_custom_backgb_color = true;
        m_background_color = color;
    }

    inline mrpt::img::TColorf getCustomBackgroundColor() const
    {
        return m_background_color;
    }

    /** Compute the 3D ray corresponding to a given pixel; this can be used to
     * allow the user to pick and select 3D objects by clicking onto the 2D
     * image.
     *  \param x_coord Horizontal coordinate with the usual meaning (0:left of
     * the viewport, W-1: right border).
     *  \param y_coord Horizontal coordinate with the usual meaning (0:top of
     * the viewport, H-1: right border).
     * \param out_cameraPose If not nullptr, will have the camera 3D pose as a
     * mrpt::poses::CPose3D. See also
     * \note (x,y) refer to VIEWPORT coordinates. Take into account this when
     * viewports do not extend to the whole window size.
     * \note x and y are double instead of integers to allow sub-pixel
     * precision.
     * \sa getCurrentCameraPose
     */
    void get3DRayForPixelCoord(
        const double x_coord, const double y_coord,
        mrpt::math::TLine3D& out_ray,
        mrpt::poses::CPose3D* out_cameraPose = nullptr) const;

    /** @} */  // end of Change or read viewport properties

    /** @name Contained objects set/get/search
        @{ */

    using const_iterator = CListOpenGLObjects::const_iterator;
    using iterator = CListOpenGLObjects::iterator;

    inline const_iterator begin() const { return m_objects.begin(); }
    inline const_iterator end() const { return m_objects.end(); }
    inline iterator begin() { return m_objects.begin(); }
    inline iterator end() { return m_objects.end(); }
    /** Delete all internal obejcts
     * \sa insert */
    void clear();

    /** Insert a new object into the list.
     *  The object MUST NOT be deleted, it will be deleted automatically by
     * this object when not required anymore.
     */
    void insert(const CRenderizable::Ptr& newObject);

    /** Compute the current 3D camera pose.
     * \sa get3DRayForPixelCoord
     */
    void getCurrentCameraPose(mrpt::poses::CPose3D& out_cameraPose) const;

    /** Changes the point of view of the camera, from a given pose.
     * \sa getCurrentCameraPose
     */
    void setCurrentCameraFromPose(mrpt::poses::CPose3D& p);

    /** Returns the first object with a given name, or nullptr if not found.
     */
    CRenderizable::Ptr getByName(const std::string& str);

    /** 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 = view.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
        size_t foundCount = 0;
        const auto* class_ID = &T::GetRuntimeClassIdStatic();
        for (const auto& o : m_objects)
            if (o && o->GetRuntimeClass()->derivedFrom(class_ID))
                if (foundCount++ == ith) return std::dynamic_pointer_cast<T>(o);

        // If not found directly, search recursively:
        for (const auto& o : m_objects)
        {
            if (o && o->GetRuntimeClass() ==
                         CLASS_ID_NAMESPACE(CSetOfObjects, mrpt::opengl))
            {
                typename T::Ptr obj = std::dynamic_pointer_cast<T>(
                    std::dynamic_pointer_cast<CSetOfObjects>(o)
                        ->template getByClass<T>(ith));
                if (obj) return obj;
            }
        }
        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);

    /** Number of objects contained. */
    inline size_t size() const { return m_objects.size(); }
    inline bool empty() const { return m_objects.empty(); }
    /** Get a reference to the camera associated with this viewport. */
    opengl::CCamera& getCamera() { return m_camera; }
    /** Get a reference to the camera associated with this viewport. */
    const opengl::CCamera& getCamera() const { return m_camera; }
    /** Evaluates the bounding box of this object (including possible children)
     * in the coordinate frame of the object parent. */
    void getBoundingBox(
        mrpt::math::TPoint3D& bb_min, mrpt::math::TPoint3D& bb_max) const;

    /** @} */  // end of Contained objects set/get/search
    // ------------------------------------------------------

    /** Destructor: clears all objects. */
    ~COpenGLViewport() override;

    /** Constructor, invoked from COpenGLScene only.
     */
    COpenGLViewport(
        COpenGLScene* parent = nullptr,
        const std::string& name = std::string(""));

    /** Render the objects in this viewport (called from COpenGLScene) */
    void render(
        const int render_width, const int render_height,
        const int render_offset_x = 0, const int render_offset_y = 0) const;

   protected:
    /** 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);

    /** Render in image mode */
    void renderImageMode() const;

    /** Render a normal scene with 3D objects */
    void renderNormalSceneMode() const;

    /** Render the viewport border, if enabled */
    void renderViewportBorder() const;

    /** The camera associated to the viewport */
    opengl::CCamera m_camera;
    /** The scene that contains this viewport. */
    mrpt::safe_ptr<COpenGLScene> m_parent;
    /** Set by setCloneView */
    bool m_isCloned{false};
    /** Set by setCloneCamera */
    bool m_isClonedCamera{false};
    /** Only if m_isCloned=true */
    std::string m_clonedViewport;
    /** The viewport's name */
    std::string m_name;
    /** Whether to clear color buffer. */
    bool m_isTransparent{false};
    /** Default=0, the border around the viewport. */
    uint32_t m_borderWidth{0};

    mrpt::img::TColor m_borderColor{255, 255, 255, 255};

    /** The viewport position [0,1] */
    double m_view_x{0}, m_view_y{0}, m_view_width{1}, m_view_height{1};
    /** The min/max clip depth distances (default: 0.1 - 10000) */
    float m_clip_min = 0.1f, m_clip_max = 10000.0f;
    bool m_custom_backgb_color{false};
    /** used only if m_custom_backgb_color */
    mrpt::img::TColorf m_background_color = {0.6f, 0.6f, 0.6f};
    /** Set by setImageView */
    bool m_isImageView{false};

    /** The image to display, after calling \a setImageView() */
    mrpt::opengl::CTexturedPlane::Ptr m_imageview_plane;

    mutable mrpt::opengl::CSetOfLines::Ptr m_borderLines;

    /** Info updated with each "render()" and used in "get3DRayForPixelCoord" */
    mutable TRenderMatrices m_state;

    /** Default shader program */
    mutable std::map<shader_id_t, mrpt::opengl::Program::Ptr> m_shaders;

    /** Load all MPRT predefined shader programs into m_shaders */
    void loadDefaultShaders() const;

    /** Unload shader programs in m_shaders */
    void unloadShaders();

    /** The list of objects that comprise the 3D scene.
     *  Objects are automatically deleted when calling "clear" or in the
     * destructor.
     */
    opengl::CListOpenGLObjects m_objects;

    void internal_enableImageView();

    // OpenGL global settings:
    bool m_OpenGL_enablePolygonNicest{true};

    TLightParameters m_lights;

    /** Renders all messages in the underlying class CTextMessageCapable */
    void renderTextMessages() const;
};

/**
 * Inserts an openGL object into a viewport. Allows call chaining.
 * \sa mrpt::opengl::COpenGLViewport::insert
 */
inline COpenGLViewport::Ptr& operator<<(
    COpenGLViewport::Ptr& s, const CRenderizable::Ptr& r)
{
    s->insert(r);
    return s;
}
/**
 * Inserts any iterable set of openGL objects into a viewport. Allows call
 * chaining.
 * \sa mrpt::opengl::COpenGLViewport::insert
 */
inline COpenGLViewport::Ptr& operator<<(
    COpenGLViewport::Ptr& s, const std::vector<CRenderizable::Ptr>& v)
{
    for (const auto& it : v) s->insert(it);
    return s;
}

/** @name Events emitted by COpenGLViewport
    @{  */

/**  An event sent by an mrpt::opengl::COpenGLViewport just after clearing the
 * viewport and setting the GL_PROJECTION matrix, and before calling the scene
 * OpenGL drawing primitives.
 *
 * While handling this event you can call OpenGL glDraw(), etc.
 *
 * IMPORTANTE NOTICE: Event handlers in your observer class will most likely be
 * invoked from an internal GUI thread of MRPT, so all your code in the handler
 * must be thread safe.
 */
class mrptEventGLPreRender : public mrpt::system::mrptEvent
{
   protected:
    /** Just to allow this class to be polymorphic */
    void do_nothing() override {}

   public:
    inline mrptEventGLPreRender(const COpenGLViewport* obj)
        : source_viewport(obj)
    {
    }
    const COpenGLViewport* const source_viewport;
};  // End of class def.

/**  An event sent by an mrpt::opengl::COpenGLViewport after calling the scene
 * OpenGL drawing primitives and before doing a glSwapBuffers
 *
 *  While handling this event you can call OpenGL glBegin(),glEnd(),gl*
 * functions or those in mrpt::opengl::gl_utils to draw stuff *on the top* of
 * the normal
 *   objects contained in the COpenGLScene.
 *
 *  IMPORTANTE NOTICE: Event handlers in your observer class will most likely
 * be invoked from an internal GUI thread of MRPT,
 *    so all your code in the handler must be thread safe.
 */
class mrptEventGLPostRender : public mrpt::system::mrptEvent
{
   protected:
    /** Just to allow this class to be polymorphic */
    void do_nothing() override {}

   public:
    inline mrptEventGLPostRender(const COpenGLViewport* obj)
        : source_viewport(obj)
    {
    }
    const COpenGLViewport* const source_viewport;
};  // End of class def.

/** @} */

}  // namespace mrpt::opengl