OpenSpace/include/openspace/navigation/navigationhandler.h

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2025                                                               *
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#ifndef __OPENSPACE_CORE___NAVIGATIONHANDLER___H__
#define __OPENSPACE_CORE___NAVIGATIONHANDLER___H__

#include <openspace/properties/propertyowner.h>

#include <openspace/navigation/keyframenavigator.h>
#include <openspace/navigation/navigationstate.h>
#include <openspace/navigation/orbitalnavigator/orbitalnavigator.h>
#include <openspace/navigation/pathnavigator.h>
#include <openspace/properties/scalar/boolproperty.h>
#include <openspace/properties/scalar/floatproperty.h>
#include <openspace/util/keys.h>
#include <openspace/util/mouse.h>
#include <ghoul/glm.h>
#include <filesystem>
#include <functional>
#include <optional>
#include <string>
#include <variant>
#include <vector>

namespace openspace {
    namespace scripting { struct LuaLibrary; }
    class Camera;
    class SceneGraphNode;
} // namespace openspace

namespace openspace::interaction {

struct NavigationState;
struct NodeCameraStateSpec;

/**
 * The NavigationHandler is responsible for updating the camera, and switching between
 * different navigation modes (navigators).
 */
class NavigationHandler : public properties::PropertyOwner {
public:
    NavigationHandler();
    virtual ~NavigationHandler() override;

    void initialize();
    void deinitialize();

    // Mutators
    void setFocusNode(SceneGraphNode* node);
    void setCamera(Camera* camera);
    void setInterpolationTime(float durationInSeconds);

    void updateCamera(double deltaTime);

    void resetNavigationUpdateVariables();

    // Accessors
    Camera* camera() const;
    const SceneGraphNode* anchorNode() const;

    const OrbitalNavigator& orbitalNavigator() const;
    OrbitalNavigator& orbitalNavigator();
    KeyframeNavigator& keyframeNavigator();
    PathNavigator& pathNavigator();

    bool isKeyFrameInteractionEnabled() const;
    float jumpToFadeDuration() const;
    float interpolationTime() const;

    NavigationState navigationState() const;
    NavigationState navigationState(const SceneGraphNode& referenceFrame) const;

    void saveNavigationState(const std::filesystem::path& filepath,
        const std::string& referenceFrameIdentifier) const;

    void loadNavigationState(const std::string& filepath, bool useTimeStamp);

    /**
     * Set camera state from a provided navigation state next frame. The actual position
     * will computed from the scene in the same frame as it is set.
     *
     * \param state The navigation state to compute a camera positon from
     */
    void setNavigationStateNextFrame(const NavigationState& state);

    /**
     * Set camera state from a provided node based camera specification structure, next
     * frame. The camera position will be computed to look at the node provided in the
     * node info. The actual position will computed from the scene in the same frame as
     * it is set.
     *
     * \param spec The node specification from which to compute the resulting camera pose
     */
    void setCameraFromNodeSpecNextFrame(NodeCameraStateSpec spec);

    /**
     * Trigger a transition script after first fading out the rendering, and fading in
     * the rendering when the script is finished. One example use case could be to fade
     * out, move the camera to another focus node, and then fade in
     *
     * \param transitionScript The Lua script to handle the transition. Can be anything
     * \param fadeDuration An optional duration for the fading. If unspecified, use the
     *                     JumpToFadeDuration property
     */
    void triggerFadeToTransition(std::string transitionScript,
        std::optional<float> fadeDuration = std::nullopt);

    /**
     * \return The Lua library that contains all Lua functions available to affect the
     *         interaction
     */
    static scripting::LuaLibrary luaLibrary();

private:
    void applyPendingState();
    void updateCameraTransitions();

    Camera* _camera = nullptr;
    std::function<void()> _playbackEndCallback;

    bool _inAnchorApproachSphere = false;
    bool _inAnchorReachSphere = false;
    const SceneGraphNode* _lastAnchor = nullptr;

    OrbitalNavigator _orbitalNavigator;
    KeyframeNavigator _keyframeNavigator;
    PathNavigator _pathNavigator;

    std::optional<std::variant<NodeCameraStateSpec, NavigationState>> _pendingState;

    properties::BoolProperty _useKeyFrameInteraction;
    properties::FloatProperty _jumpToFadeDuration;
};

} // namespace openspace::interaction

#endif // __OPENSPACE_CORE___NAVIGATIONHANDLER___H__