Question

我正在尝试通过自己的游戏引擎来创建游戏引擎，其中每个基本引擎都是一个GameObject，其中将包含一个更新功能和其他通知程序。

到目前为止，这是我的代码：

#include <SFML/Audio.hpp>
#include <SFML/Graphics.hpp>
#include "AssetManager.hpp"

class GameObject : public sf::Drawable, public sf::Transformable
{
public:
  virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const{
    target.draw(*this, states);
  };
};

class Sprite : public GameObject, public sf::Sprite {
public:
  Sprite(AssetManager assetManager, std::string assetName) : sf::Sprite(){
    setTexture(assetManager.getTextureNamed(assetName));
  }
};


int main(int argc, char const** argv)
{
  sf::RenderWindow window(sf::VideoMode::getDesktopMode(), "");
  AssetManager assetManager = AssetManager("/Users/iProgram/Desktop/My Game Engine/My Game Engine");
  assetManager.loadTextureWithName("tank", "tank.png", sf::Vector2f(16,16));

  Sprite tank = Sprite(assetManager, "tank");

  while(window.isOpen()){
    window.clear();
    window.draw(tank);
    window.display();
  }

  return EXIT_SUCCESS;
}

请注意，资产管理器只是将纹理存储在内存中，并在需要时以给定大小返回纹理。

问题在线上：window.draw(tank);，我收到了错误消息

从派生类'const Sprite'到基类'const sf :: Drawable'的不明确转换：

这是为什么，因为我在GameObject类中实现了draw函数，我该如何解决？

Answer 1

您的Sprite类继承自GameObject，而sf::Drawable继承自sf::Sprite。您的课程还继承自sf::Drawable，而也继承自Sprite。现在，您的sf::Drawable类具有2个继承的from tensorflow.keras.models import Sequential import tensorflow_probability as tfp import tensorflow as tf def train_BNN(training_data, training_labels, test_data, test_labels, layers, epochs): bayesian_nn = Sequential() nbr_samples, dim = training_data.shape training_labels = training_labels.reshape((nbr_samples, 1)) training_data = tf.convert_to_tensor(training_data, tf.float32) training_labels = tf.convert_to_tensor(training_labels, tf.float32) for i in range(0, len(layers)): bayesian_nn.add(tfp.layers.DenseFlipout(layers[i], activation='relu')) bayesian_nn.add(tfp.layers.DenseFlipout(1, activation='sigmoid')) # Define loss function logits = bayesian_nn(training_data) neg_log_likelihood = tf.losses.sigmoid_cross_entropy(training_labels, logits=logits) kl = sum(bayesian_nn.losses) loss = neg_log_likelihood + kl # Define optimizer train_op = tf.train.AdamOptimizer().minimize(loss) bayesian_nn.compile(train_op, loss=loss, metrics=['accuracy'])子对象，编译器无法选择。

要解决此问题，请重新考虑您的设计或虚拟继承。

Answer 2

要解决此问题，我不必像某些建议那样使用私有继承，我只需要基类（GameObject）即可不继承任何内容。然后，我的Sprite类将继承sf::Sprite，如下所示：

#include <SFML/Audio.hpp>
#include <SFML/Graphics.hpp>
#include "AssetManager.hpp"

class GameObject{
public:
  virtual void update(){}
};

class Sprite : public GameObject, public sf::Sprite {
public:
  Sprite(AssetManager* assetManager, std::string assetName) : sf::Sprite(assetManager->getTextureNamed(assetName)){
  }
};

class Tank: public Sprite{
public:
  Tank(AssetManager* assetManager) : Sprite(assetManager, "tank"){
    setScale(3, 3);
  };

  virtual void update(){
    move(1,0);
  }
};

int main(int argc, char const** argv)
{
  sf::RenderWindow window(sf::VideoMode::getDesktopMode(), "");
  AssetManager* assetManager = new AssetManager("/Users/iProgram/Desktop/My Game Engine/My Game Engine");
  assetManager->loadTextureWithName("tank", "tank.png", sf::Vector2f(16,16));

  Tank tank = Tank(assetManager);
  while(window.isOpen()){
    sf::Event event;
    while(window.pollEvent(event)){
      if(event.type == sf::Event::Closed){
        window.close();
      }
    }
    tank.update();
    window.clear();
    window.draw(tank);
    window.display();
  }

  return EXIT_SUCCESS;
}

实施绘图功能时，SFML无法从派生类进行转换

2 个答案: