SpriteKit使用applyImpulse移动了physicsBody [英] SpriteKit move rotated physicsBody with applyImpulse

问题描述

我想在一个基于physicsBody旋转的方向上使用applyImpulse方法移动一个physicsBody。

I want to move a physicsBody with the applyImpulse method in a direction based on the physicsBody rotation.

例如，physicsBody是一个方形的形状，我打电话一个移动，它将施加一个冲动，使其垂直向上移动。然后我调用一个方法将physicsBody旋转45度。如果我再次调用移动方法，物理对象将向右对角移动。

Foe example, the physicsBody is a square in shape, I call a "move" which will apply an impulse to make it move up vertically. I then call a method to rotate the physicsBody 45 degrees right. If I call the "move" method again, the physicsBody will move diagonally right and up.

任何人都可以帮忙吗？

推荐答案

我建议您遵循Sprite Kit的坐标和旋转约定。具体来说，您的精灵图像应该面向零度（默认值），正值是逆时针旋转。也就是说，这是在精灵面临的方向上施加冲动的一种方法：

I suggest that you follow Sprite Kit’s coordinate and rotation conventions. Specifically, your sprite image should be facing right at zero degrees (the default value), and a positive value is a counter-clockwise rotation. That said, here's one way to apply an impulse in the direction a sprite is facing:

// Specify the force to apply to the SKPhysicsBody
CGFloat r = 5;

// Create a vector in the direction the sprite is facing
CGFloat dx = r * cos (sprite.zRotation);
CGFloat dy = r * sin (sprite.zRotation);

// Apply impulse to physics body
[sprite.physicsBody applyImpulse:CGVectorMake(dx,dy)];

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