boost::python - 如何通过引用/指针传递给 python 覆盖的类函数

Question

我有一些通过指针接收参数的类函数。但是，当我在 boost::python 中公开和覆盖这些函数时，我对参数所做的任何更改都不会反映回原始参数，这意味着它没有像我预期的那样通过指针传递。我以前将它们作为传递引用，但仍然出现同样的问题。对于我的意思的一个例子，这是我的一些代码，其中省略了不重要的功能和细节。

class StatusEffect
{
public:
      virtual void TickCharacter(Character::BaseCharacter* character, Battles::BattleField *field, int ticks = 1);
}
//In my Scripting Code header file

struct StatusEffectWrapper : Game::StatusEffects::StatusEffect
{
    virtual void TickCharacter(Game::Character::BaseCharacter* character, Game::Battles::BattleField *field, int ticks = 1);
    virtual void TickCharacterDefault(Game::Character::BaseCharacter* character, Game::Battles::BattleField *field, int ticks = 1);
}
//In the actual scripting code
    void StatusEffectWrapper::TickCharacter(Game::Character::BaseCharacter* character, Game::Battles::BattleField *field, int ticks)
    {
        call_method<void>(self, "TickCharacter", character, field, ticks);
    }
    void StatusEffectWrapper::TickCharacterDefault(Game::Character::BaseCharacter* character, Game::Battles::BattleField *field, int ticks)
    {
        this->StatusEffect::TickCharacter(character, field, ticks);
    }

    class_<StatusEffects::StatusEffect, boost::shared_ptr<StatusEffectWrapper> >("StatusEffect")
    .def("TickCharacter", &StatusEffect::TickCharacter, &StatusEffectWrapper::TickCharacterDefault)

最后在我的 Python 文件中，我尝试做这样的事情

class StatCreepEffect(StatusEffect):
    def __init__(self, name, stat_, rate_, descript, uid, turns, prior, canrefresh, poseffect, cats, conds, flgs, sep, pers):
        StatusEffect.__init__(self, name, descript, uid, turns, prior, canrefresh, poseffect, cats, conds, flgs, sep, pers)
        self.rate = rate_
        self.stat = stat_
    def TickCharacter(self, Character, Field, Ticks):
        if (self.stat == Stat.HP):
            Character.SetHP(int(round(Character.GetHP() + Character.GetInBattleStat(self.stat) * self.rate)))
            print("HP Regenerated on character " + Character.GetName() + " New HP: " + str(Character.GetHP()))
        elif (self.stat == Stat.MP):
            Character.SetMP(int(round(Character.GetMP() + Character.GetInBattleStat(self.stat) * self.rate)))
        elif (self.stat == Stat.SP):
            Character.SetSP(int(round(Character.SetSP() + Character.GetInBattleStat(self.stat) * self.rate)))

Regen = StatCreepEffect("Regen", Stat.HP, 0.05, "Regenerates a small amount of HP every turn", PrimaryEngine.GetUID(), 14, 0, True, True, StatusCategories.SC_Regen, 0, StatusFlags.TickEffect, True, StatusPersistence.SP_Timer_Cure)

SELibrary.AddPythonEffect(Regen);

我在我的 C++ 代码中这样称呼效果

StatusEffect* regen = game.GetSELibrary().GetStatusEffect(std::string("Regen"));
while(character.GetHP() < 600)
    {
regen->TickCharacter(&character, &field, 1);
        std::cout << "Character HP: " << character.GetHP() << std::endl;
    }

我按照此处http://wiki.python.org/moin/boost.python/OverridableVirtualFunctions的示例创建了此代码

脚本编译并正确添加效果。 python 脚本中的打印行打印正确的值。字符对象以 400 HP 开头，打印行输出 430。但是，我的 C++ 代码中的 std::cout 行始终输出 400，这意味着脚本添加的额外 30 HP 不会反映在原始对象中。为清楚起见，以下是上述 C++ 代码片段的控制台输出：

HP Regenerated on character Arian New HP: 430
Character HP: 400

有人可以帮我弄清楚如何使它正常工作吗？将不胜感激。

谢谢

如果重要，AddPythonEffect 定义如下：

void StatusEffectsLibrary::AddPythonEffect(boost::shared_ptr<StatusEffect> effect)
{
    if (effect.get() != nullptr)
    {
        NameToSEMap[effect->GetName()] = effect;
        IDToSEMap[effect->GetUID()] = effect;
    }
}

Answer 1

经过一番搜索，我找到了答案。事实证明，您必须明确指示 call_method 在通过引用（通过使用 ref(T)）或指针（通过使用 ptr(T)）传递时不要进行复制。 通过改变

void StatusEffectWrapper::TickCharacter(Game::Character::BaseCharacter* character, Game::Battles::BattleField *field, int ticks)
{
    call_method<void>(self, "TickCharacter", character, field, ticks);
}

到

void StatusEffectWrapper::TickCharacter(Game::Character::BaseCharacter* character, Game::Battles::BattleField *field, int ticks)
{
    call_method<void>(self, "TickCharacter", ptr(character), ptr(field), ticks);
}

我得到了我想要的行为。