Cocos2d-x box2d applyforce方向

Question

如何对箭头精灵方向施加力？我需要申请箭头旋转。

感谢。

Answer 1

这是一种方法：

cocos2d::Sprite* arrow = ...   // defined here
b2Body* body = ...             // defined here

// Get the arrow rotation in cocos2d world (deg), and transform it to Box2D world (rad).
float angle = CC_DEGREES_TO_RADIANS(-1 * arrow->getRotation());
// Set the magnitude of the force. It can be any positive number.
float mag = 1;
// Calculate the force vector.
b2Vec2 force(mag * cosf(angle), mag * sinf(angle));

body->ApplyForceToCenter(force, true);