Godot 4.1 GDExtension多C++源共享库问题：Summator无法调用

问题现象 #

基于Summator示例开发，新增Cppkinematics的C++源文件后，将两者整合到名为godotcppsharedlib的共享库中。GDScript可正常调用Cppkinematics类，但原Summator类无法使用，场景脚本报错：

Identifier Summator not declared in the current scope

疑似问题文件内容 #

game/bin/godotcppsharedlib.gdextension #

[configuration]
entry_symbol = "godotcppsharedlib_library_init"
compatibility_minimum = 4.1
[libraries]
windows.x86_64.debug = "res://bin/libgdgodotcppsharedlib.windows.template_debug.x86_64.dll"
windows.x86_64.release = "res://bin/libgdgodotcppsharedlib.windows.template_release.x86_64.dll"

game.godot/extension_list.cfg #

res://bin/godotcppsharedlib.gdextension

extension/src/register_types.cpp #

#include "register_types.h"
#include "summator.h"
#include "cppkinematics.h"
#include <gdextension_interface.h>
#include <godot_cpp/core/class_db.hpp>
#include <godot_cpp/core/defs.hpp>
#include <godot_cpp/godot.hpp>

using namespace godot;

void initialize_summator_types(ModuleInitializationLevel p_level)
{
    if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
        return;
    }
    ClassDB::register_class<Summator>();
}

void uninitialize_summator_types(ModuleInitializationLevel p_level) {
    if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
        return;
    }
}

void initialize_cppkinematics_types(ModuleInitializationLevel p_level)
{
    if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
        return;
    }
    ClassDB::register_class<Cppkinematics>();
}

void uninitialize_cppkinematics_types(ModuleInitializationLevel p_level) {
    if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
        return;
    }
}

extern "C"
{
    GDExtensionBool GDE_EXPORT godotcppsharedlib_library_init(GDExtensionInterfaceGetProcAddress p_get_proc_address, GDExtensionClassLibraryPtr p_library, GDExtensionInitialization *r_initialization) {
        GDExtensionBinding::InitObject init_obj(p_get_proc_address, p_library, r_initialization);
        init_obj.register_initializer(initialize_summator_types);
        init_obj.register_terminator(uninitialize_summator_types);
        init_obj.register_initializer(initialize_cppkinematics_types);
        init_obj.register_terminator(uninitialize_cppkinematics_types);
        init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);
        return init_obj.init();
    }
}

extension/src/register_types.h #

#ifndef SUMMATOR_REGISTER_TYPES_H
#define SUMMATOR_REGISTER_TYPES_H
void initialize_summator_types();
void uninitialize_summator_types();
#endif // SUMMATOR_REGISTER_TYPES_H

#ifndef CPPKINEMATICS_REGISTER_TYPES_H
#define CPPKINEMATICS_REGISTER_TYPES_H
void initialize_cppkinematics_types();
void uninitialize_cppkinematics_types();
#endif // CPPKINEMATICS_REGISTER_TYPES_H

SConstruct #

#!/usr/bin/env python
import os
import sys
env = SConscript("godot-cpp/SConstruct")
env.Append(CPPPATH=["extension/src/"])
sources = Glob("extension/src/*.cpp")

if env["platform"] == "macos":
    library = env.SharedLibrary(
        "game/bin/libgdgodotcppsharedlib.{}.{}.framework/godotcppsharedlib.{}.{}".format(
            env["platform"], env["target"], env["platform"], env["target"]
        ),
        source=sources,
    )
else:
    library = env.SharedLibrary(
        "game/bin/libgdgodotcppsharedlib{}{}".format(env["suffix"], env["SHLIBSUFFIX"]),
        source=sources,
    )
Default(library)

问题根源 #

register_types.h中声明的初始化/终止函数与register_types.cpp中的定义参数不匹配：

• 头文件中函数声明为无参数（如void initialize_summator_types();）
• 源文件中函数定义携带ModuleInitializationLevel参数（如void initialize_summator_types(ModuleInitializationLevel p_level)）

这种不匹配会导致编译器将声明与定义视为两个完全不同的函数，初始化流程中实际调用的是未实现的无参数版本，而真正执行Summator注册逻辑的带参数函数从未被调用，最终导致Summator类未注册到Godot的ClassDB中。

解决方案 #

1. 修正register_types.h中的函数声明，为所有初始化/终止函数添加godot::ModuleInitializationLevel参数：

#ifndef SUMMATOR_REGISTER_TYPES_H
#define SUMMATOR_REGISTER_TYPES_H
void initialize_summator_types(godot::ModuleInitializationLevel p_level);
void uninitialize_summator_types(godot::ModuleInitializationLevel p_level);
#endif // SUMMATOR_REGISTER_TYPES_H

#ifndef CPPKINEMATICS_REGISTER_TYPES_H
#define CPPKINEMATICS_REGISTER_TYPES_H
void initialize_cppkinematics_types(godot::ModuleInitializationLevel p_level);
void uninitialize_cppkinematics_types(godot::ModuleInitializationLevel p_level);
#endif // CPPKINEMATICS_REGISTER_TYPES_H

2. 重新编译共享库：执行scons命令重新构建扩展库。
3. 重启Godot编辑器，刷新场景脚本，验证Summator类是否可正常调用。

内容的提问来源于stack exchange，提问作者Pansophical T