godot-cpp-utils/player_input.hpp

#ifndef PLAYER_INPUT_HPP
#define PLAYER_INPUT_HPP

#include <vector>
#include <optional>
#include "godot_cpp/classes/input.hpp"
#include "godot_cpp/classes/input_event.hpp"
#include "godot_cpp/classes/node.hpp"
#include "godot_cpp/variant/callable.hpp"

namespace godot {
class PlayerInput : public Node {
    GDCLASS(PlayerInput, Node)
    static void _bind_methods();
public:
    // a listener is a combination of a positive and negative action and a listener function.
    // listener functions use godot's Object::call function.
    // So they require a Node instance and a function name.
    // The expected signature is void(Ref<InputEvent>, float)
    // actions can also be "special" actions prefixed with _.
    // special actions include _mouse_up, _mouse_down, _mouse_left and _mouse_right
    // which rather than checking action_is_down,
    // will use PlayerInput::get_last_mouse_motion() to poll the current state.
    struct Listener {
        friend class PlayerInput;
    private:
        // the two actions, evaluated as positive - negative
        String actionNegative{""};
        String actionPositive{""};
        // the last cached action, if the newest result matches this, the event will be considered
        // duplicate and ignored (not passed to listener)
        float lastCached{0.f};
        Callable callable;
        // if either actionNegative or actionPositive is a _mouse_ event this will be true
        bool isMouseEvent{false};

    public:
        Listener(String positive, String negative, Callable callable);
        Listener(String action, Callable callable);
        // evaluate the current state of an action.
        static std::optional<float> evaluate_action(String const &action);
        // check if this event has any chance to result in a trigger, does not evaluate the event or
        // poll current input state
        bool has_changed(Ref<InputEvent> const &event);
        // evaluate the event for changes to either actionPositive or actionNegative
        float evaluate(Ref<InputEvent> const &event);

        bool operator==(godot::PlayerInput::Listener const& b);
    };
private:
    // the last mouse motion, updated by the primary instance
    static Vector2 lastMouseMotion;
    // does a primary instance exist
    static bool primaryExists;
    // is this the primary instance
    // the primary instance is responsible for updating static
    // variables like lastMouseMotion
    bool isPrimary{false};

    // current listeners for this instance
    std::vector<Listener> listeners{};
public:
    static Vector2 get_last_mouse_motion();

    virtual void _enter_tree() override;
    virtual void _exit_tree() override;
    virtual void _unhandled_input(Ref<InputEvent> const &event) override;
    virtual void _process(double deltaTime) override;

    void listen_to(Listener const& listener);
    void stop_listening(Node *node);
    void stop_listening(Listener const& listener);
};
}


#endif // !PLAYER_INPUT_HPP