自定义Godot服务

前言

Godot将多线程实现为服务器. 服务器是管理数据, 处理数据和推送结果的守护进程. 服务器实现中介模式, 该模式解释引擎和其他模块的资源ID和处理数据. 此外, 服务器声明其RID分配的所有权. 自定义 C++ 模块.

参考

  • 为什么Godot使用服务与RID ？
  • 单例模式
  • 中介模式

    可以做什么？

  • 添加人工智能.
  • 添加自定义异步线程.
  • 添加对新输入设备的支持.
  • 添加写线程.
  • 添加自定义VoIP协议.
  • 以及更多…

    创建Godot服务

    至少, 服务必须具有静态实例, 睡眠计时器, 线程循环, 初始化状态, 和清理过程.
    1. #ifndef HILBERT_HOTEL_H#define HILBERT_HOTEL_H#include "core/list.h"#include "core/object.h"#include "core/os/thread.h"#include "core/os/mutex.h"#include "core/rid.h"#include "core/set.h"#include "core/variant.h"class HilbertHotel : public Object {        GDCLASS(HilbertHotel, Object);        static HilbertHotel *singleton;        static void thread_func(void *p_udata);private:        bool thread_exited;        mutable bool exit_thread;        Thread *thread;        Mutex *mutex;public:        static HilbertHotel *get_singleton();        Error init();        void lock();        void unlock();        void finish();protected:        static void _bind_methods();private:        uint64_t counter;        RID_Owner<InfiniteBus> bus_owner;        // https://github.com/godotengine/godot/blob/3.x/core/rid.h#L196        Set<RID> buses;        void _emit_occupy_room(uint64_t room, RID rid);public:        RID create_bus();        Variant get_bus_info(RID id);        bool empty();        bool delete_bus(RID id);        void clear();        void register_rooms();        HilbertHotel();};#endif
    1. #include "hilbert_hotel.h"#include "core/dictionary.h"#include "core/list.h"#include "core/os/os.h"#include "core/variant.h"#include "prime_225.h"void HilbertHotel::thread_func(void *p_udata) {        HilbertHotel *ac = (HilbertHotel *) p_udata;        uint64_t msdelay = 1000;        while (!ac->exit_thread) {                if (!ac->empty()) {                        ac->lock();                        ac->register_rooms();                        ac->unlock();                }                OS::get_singleton()->delay_usec(msdelay * 1000);        }}Error HilbertHotel::init() {        thread_exited = false;        counter = 0;        mutex = Mutex::create();        thread = Thread::create(HilbertHotel::thread_func, this);        return OK;}HilbertHotel *HilbertHotel::singleton = NULL;HilbertHotel *HilbertHotel::get_singleton() {        return singleton;}void HilbertHotel::register_rooms() {        for (Set<RID>::Element *e = buses.front(); e; e = e->next()) {                auto bus = bus_owner.getornull(e->get());                if (bus) {                        uint64_t room = bus->next_room();                        _emit_occupy_room(room, bus->get_self());                }        }}void HilbertHotel::unlock() {        if (!thread || !mutex) {                return;        }        mutex->unlock();}void HilbertHotel::lock() {        if (!thread || !mutex) {                return;        }        mutex->lock();}void HilbertHotel::_emit_occupy_room(uint64_t room, RID rid) {        _HilbertHotel::get_singleton()->_occupy_room(room, rid);}Variant HilbertHotel::get_bus_info(RID id) {        InfiniteBus *)bus = bus_owner.getornull(id);        if (bus) {                Dictionary d;                d["prime"] = bus->get_bus_num();                d["current_room"] = bus->get_current_room();                return d;        }        return Variant();}void HilbertHotel::finish() {        if (!thread) {                return;        }        exit_thread = true;        Thread::wait_to_finish(thread);        memdelete(thread);        if (mutex) {                memdelete(mutex);        }        thread = NULL;}RID HilbertHotel::create_bus() {        lock();        InfiniteBus *ptr = memnew(InfiniteBus(PRIME[counter++]));        RID ret = bus_owner.make_rid(ptr);        ptr->set_self(ret);        buses.insert(ret);        unlock();        return ret;}// https://github.com/godotengine/godot/blob/3.x/core/rid.h#L187bool HilbertHotel::delete_bus(RID id) {        if (bus_owner.owns(id)) {                lock();                InfiniteBus *b = bus_owner.get(id);                bus_owner.free(id);                buses.erase(id);                memdelete(b);                unlock();                return true;        }        return false;}void HilbertHotel::clear() {        for (Set<RID>::Element *e = buses.front(); e; e = e->next()) {                delete_bus(e->get());        }}bool HilbertHotel::empty() {        return buses.size() <= 0;}void HilbertHotel::_bind_methods() {}HilbertHotel::HilbertHotel() {        singleton = this;}
    1. /* prime_225.h */#include "core/int_types.h"const uint64_t PRIME[225] = {                2,3,5,7,11,13,17,19,23,                29,31,37,41,43,47,53,59,61,                67,71,73,79,83,89,97,101,103,                107,109,113,127,131,137,139,149,151,                157,163,167,173,179,181,191,193,197,                199,211,223,227,229,233,239,241,251,                257,263,269,271,277,281,283,293,307,                311,313,317,331,337,347,349,353,359,                367,373,379,383,389,397,401,409,419,                421,431,433,439,443,449,457,461,463,                467,479,487,491,499,503,509,521,523,                541,547,557,563,569,571,577,587,593,                599,601,607,613,617,619,631,641,643,                647,653,659,661,673,677,683,691,701,                709,719,727,733,739,743,751,757,761,                769,773,787,797,809,811,821,823,827,                829,839,853,857,859,863,877,881,883,                887,907,911,919,929,937,941,947,953,                967,971,977,983,991,997,1009,1013,1019,                1021,1031,1033,1039,1049,1051,1061,1063,1069,                1087,1091,1093,1097,1103,1109,1117,1123,1129,                1151,1153,1163,1171,1181,1187,1193,1201,1213,                1217,1223,1229,1231,1237,1249,1259,1277,1279,                1283,1289,1291,1297,1301,1303,1307,1319,1321,                1327,1361,1367,1373,1381,1399,1409,1423,1427};

    自定义托管资源数据

    RID_Data . RID_Owner <MyRID_Data> 在调用 make_rid 时拥有对象. 仅在调试模式期间,RID_Owner维护RID列表. 实际上,RID类似于编写面向对象的C代码.
    1. class InfiniteBus : public RID_Data {        RID self;private:        uint64_t prime_num;        uint64_t num;public:        uint64_t next_room() {                return prime_num * num++;        }        uint64_t get_bus_num() const {                return prime_num;        }        uint64_t get_current_room() const {                return prime_num * num;        }        _FORCE_INLINE_ void set_self(const RID &p_self) {                self = p_self;        }        _FORCE_INLINE_ RID get_self() const {                return self;        }        InfiniteBus(uint64_t prime) : prime_num(prime), num(1) {};        ~InfiniteBus() {};}

    参考

  • RID
  • core/rid.h

    在GDScript中注册类

    register_types.cpp 中分配. 构造函数设置静态实例, init() 创建托管线程； unregister_types.cpp 清理服务. 由于Godot服务类创建了一个实例并将其绑定到静态单例, 因此绑定该类可能不会引用正确的实例. 因此, 必须创建一个虚拟类来引用正确的Godot服务. register_server_types() 中，Engine :: get_singleton() -> add_singleton 用于在 GDScript 中注册虚拟类。
    1. /* register_types.cpp */#include "register_types.h"#include "core/class_db.h"#include "core/engine.h"#include "hilbert_hotel.h"static HilbertHotel *hilbert_hotel = NULL;static _HilbertHotel *_hilbert_hotel = NULL;void register_hilbert_hotel_types() {        hilbert_hotel = memnew(HilbertHotel);        hilbert_hotel->init();        _hilbert_hotel = memnew(_HilbertHotel);        ClassDB::register_class<_HilbertHotel>();        Engine::get_singleton()->add_singleton(Engine::Singleton("HilbertHotel", _HilbertHotel::get_singleton()));}void unregister_hilbert_hotel_types() {        if (hilbert_hotel) {                hilbert_hotel->finish();                memdelete(hilbert_hotel);        }        if (_hilbert_hotel) {                memdelete(_hilbert_hotel);        }}
    1. /* register_types.h *//* Yes, the word in the middle must be the same as the module folder name */void register_hilbert_hotel_types();void unregister_hilbert_hotel_types();
  • servers/register_server_types.cpp

    绑定方法

    虚拟类将单例方法绑定到GDScript. 在大多数情况下, 虚拟类方法封装在内.
    1. Variant _HilbertHotel::get_bus_info(RID id) {        return HilbertHotel::get_singleton()->get_bus_info(id);}
    绑定信号 可以通过调用GDScript虚拟对象向GDScript发出信号.
    1. void HilbertHotel::_emit_occupy_room(uint64_t room, RID rid) {        _HilbertHotel::get_singleton()->_occupy_room(room, rid);}
    1. class _HilbertHotel : public Object {        GDCLASS(_HilbertHotel, Object);        friend class HilbertHotel;        static _HilbertHotel *singleton;protected:        static void _bind_methods();private:        void _occupy_room(int room_number, RID bus);public:        RID create_bus();        void connect_signals();        bool delete_bus(RID id);        static _HilbertHotel *get_singleton();        Variant get_bus_info(RID id);        _HilbertHotel();        ~_HilbertHotel();};#endif
    1. _HilbertHotel *_HilbertHotel::singleton = NULL;_HilbertHotel *_HilbertHotel::get_singleton() { return singleton; }RID _HilbertHotel::create_bus() {        return HilbertHotel::get_singleton()->create_bus();}bool _HilbertHotel::delete_bus(RID rid) {        return HilbertHotel::get_singleton()->delete_bus(rid);}void _HilbertHotel::_occupy_room(int room_number, RID bus) {        emit_signal("occupy_room", room_number, bus);}Variant _HilbertHotel::get_bus_info(RID id) {        return HilbertHotel::get_singleton()->get_bus_info(id);}void _HilbertHotel::_bind_methods() {        ClassDB::bind_method(D_METHOD("get_bus_info", "r_id"), &_HilbertHotel::get_bus_info);        ClassDB::bind_method(D_METHOD("create_bus"), &_HilbertHotel::create_bus);        ClassDB::bind_method(D_METHOD("delete_bus"), &_HilbertHotel::delete_bus);        ADD_SIGNAL(MethodInfo("occupy_room", PropertyInfo(Variant::INT, "room_number"), PropertyInfo(Variant::_RID, "r_id")));}void _HilbertHotel::connect_signals() {        HilbertHotel::get_singleton()->connect("occupy_room", _HilbertHotel::get_singleton(), "_occupy_room");}_HilbertHotel::_HilbertHotel() {        singleton = this;}_HilbertHotel::~_HilbertHotel() {}

    MessageQueue

    push_call, push_set, 或 push_notification 执行所需的行为. 每当执行 SceneTree::idle 或 SceneTree::iteration 时, 都会刷新队列.

    参考：

  • core/message_queue.cpp

    总结

    这是GDScript示例代码:
    1. extends Nodefunc _ready():    print("Start debugging")    HilbertHotel.connect("occupy_room", self, "_print_occupy_room")    var rid = HilbertHotel.create_bus()    OS.delay_msec(2000)    HilbertHotel.create_bus()    OS.delay_msec(2000)    HilbertHotel.create_bus()    OS.delay_msec(2000)    print(HilbertHotel.get_bus_info(rid))    HilbertHotel.delete_bus(rid)    print("Ready done")func _print_occupy_room(room_number, r_id):    print("Room number: "  + str(room_number) + ", RID: " + str(r_id))    print(HilbertHotel.get_bus_info(r_id))

    注意

  • 希尔伯特旅馆悖论 是不可能的.
  • 连接信号的示例代码是很旁门左道的.