ios – Sprite Kit – 使用Impulse在角色上射击射弹

>计算从抛射物发射器到鸟类的矢量分量
>标准化组件(可选)
>通过缩放(标准化)组件来创建矢量
>使用矢量向射弹施加冲动

这是一个如何做到这一点的例子

OBJ-C

// Calculate vector components x and y
CGFloat dx = bird.position.x - launcher.position.x;
CGFloat dy = bird.position.y - launcher.position.y;

// Normalize the components
CGFloat magnitude = sqrt(dx*dx+dy*dy);
dx /= magnitude;
dy /= magnitude;

// Create a vector in the direction of the bird
CGVector vector = CGVectorMake(strength*dx,strength*dy);

// Apply impulse
[projectile.physicsBody applyImpulse:vector];

迅速

// Calculate vector components x and y
var dx = bird.position.x - launcher.position.x
var dy = bird.position.y - launcher.position.y

// Normalize the components
let magnitude = sqrt(dx*dx+dy*dy)
dx /= magnitude
dy /= magnitude

// Create a vector in the direction of the bird
let vector = CGVector(dx:strength*dx,dy:strength*dy)

// Apply impulse
projectile.physicsBody?.applyImpulse(vector)