init

src/Movable.ts

@@ -4,6 +4,7 @@ export default class Movable extends FYGE.Sprite {
 
     private _velocity: Vector2;
     set velocity(val: Vector2) { this._velocity = val }
+    get velocity() { return this._velocity }
     private _acceleration: Vector2;
     set acceleration(val: Vector2) { this._acceleration = val }
 

src/addGame.ts

@@ -7,7 +7,7 @@ export function addGame(stage: FYGE.Stage) {
 
     const bird = stage.addChild(new Bird());//有加速度
     bird.position.set(300, 200);
-    bird.velocity = new Vector2(0, 2);
+    bird.velocity = new Vector2(0, 0);
     bird.acceleration=new Vector2(0, .5);
 
     const bird2 = stage.addChild(new Bird());//无加速度