变换无视 sf::Sprite 的起源 [英] Transformations igrnores sf::Sprite's origin

问题描述

在 SFML 中转换精灵，不考虑它的新来源.

Transforming a sprite in SFML, does not regard it's new origin.

在我的例子中，sf::Sprite 围绕左上角 ({0,0}) 的轴旋转，不管它的原点是什么.之前使用 .setOrigin() 设置新原点无效.

In my case sf::Sprite is rotating around the axis that is in the left top corner ({0,0}) regardless its origin. Setting new origin with .setOrigin() earlier takes no effect.

我确信精灵更早地获得了正确的原点位置，即矩形的中心.

I am sure that sprite is getting the right origin position earlier which is center of rectangle.

我的代码:

在我的每个 Card 类构造函数中，我都设置了我的精灵的原点.

In each of my Card class constructors I set the origin of my sprite.

card_sprite.setOrigin(Card::get_default_single_card_size().x*Game::get_scale()/2,Card::get_default_single_card_size().y*Game::get_scale()/2);

然后在我的 Deck 类中，它的行为类似于 std::stack of Cards 我使用函数:

And then in my Deck class which behaves like std::stack of Cards I use function:

void Deck::push(const Card& crd)
{
    push_back(crd);
    ..//
    std::default_random_engine generator;
    std::uniform_real_distribution<float> distributor(0,360);
    top().setRotation(distributor(generator));
}

Card::setRotaion() 看起来像这样，(仍然围绕左上角旋转卡片):

Card::setRotaion() looks like this, (which stil rotates card around top left corner) :

void Card::setRotation(float angle)
{
    card_sprite.setRotation(angle);
}

提前感谢您的帮助

推荐答案

实际上 sf::Transform 中的大多数方法都接受额外的参数来指定中心转换，根据 https://stackoverflow.com/users/7703024/super 对我的问题的评论主题:如何设置原点"sfml 中的变换

Actually most methods in sf::Transform accept extra arguments to specify a center for the transformation, as per https://stackoverflow.com/users/7703024/super 's comment on my question on the same theme : How to "set the origin" of a Transform in sfml

我不太确定你的代码，但我可能遇到过类似的问题.
我解决"了它(以一种非常不理想的方式)在使用 sf::Transforms 时，将每次对 sfml 绘图函数的调用替换为对自定义函数的调用.

I'm not too sure from your code, but I might've come up against a similar problem.
I "solved" it (in a very not ideal way) by replacing every call to a sfml drawing function with a call to a custom function when using sf::Transforms.

例如:而不是做类似的事情:

eg: instead of doing something like:

window.draw(thing, my_transform); 

我必须这样做:

draw_transformed(thing, my_transform, window)

draw_transformed 的代码如下所示:

void draw_transformed (sf::Shape const& thing, sf::Transform const& t, sf::RenderWindow& window) // cf note (1)
{
  sf::Vector2f pos = thing.getPosition();
  sf::Transform go_to_zero;
  go_to_zero.translate(-pos);
  sf::Transform go_back;
  go_back.translate(pos);
  sf::Transform conjugated_transform = go_back * t * go_to_zero ;
  window.draw(thing, conjugated_transform);
  
}

(1) 我们不能使用 sf::Drawable 作为 thing 的类型，因为在 sfml 中并不是所有可绘制的东西都有 getPosition> 方法，所以我们必须重载函数或者做一些复杂"的事情；超越这个例子.

(1) we can't use sf::Drawable as the type of thing because in sfml not all drawable things have a getPosition method, so we have to overload the function or do something "complicated" to go beyond this example.

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