效果：
实现：
组件：cc.Sprite， ReactArc
ReactArc
const { executeInEditMode, ccclass, property } = cc._decorator;
@ccclass
@executeInEditMode
export default class ReactArc extends cc.Component {
@property(cc.Node)
target: cc.Node = null;
@property
maxRange = 0.3;
@property
minRange = 0.05;
_face: cc.Sprite = null;
get face() {
if (!this._face) {
this._face = this.getComponent(cc.Sprite);
}
return this._face;
}
update(dt: number) {
if (CC_EDITOR) {
if (cc.isValid(this.target)) {
let sub = this.target.position.sub(this.node.position);
let dis = sub.mag();
let rad = cc.v2(sub).signAngle(cc.Vec2.RIGHT);
let deg = cc.misc.radiansToDegrees(rad) + 180;
this.face.fillRange = (1 - (dis / 500)) * (this.maxRange - this.minRange);
if (this.face.fillRange < 0.05) {
this.face.fillRange = 0.05;
}
else if (this.face.fillRange > 0.3) {
this.face.fillRange = 0.3;
}
this.face.fillStart = (-deg / 360 - this.face.fillRange / 2);
}
}
}
}
