Matter.js鼠标约束

Question

问题：鼠标点击时给小球施加力模拟投篮动作，但同时也可以通过鼠标拖动小球，怎么去掉拖动小球这个功能？

// add mouse control
let mouse = Mouse.create(render.canvas),
mouseConstraint = MouseConstraint.create(engine, {
    mouse: mouse,
    constraint: {
      stiffness: 0.2,
      render: {
        visible: false
      }
    }
  });
World.add(world, mouseConstraint);

// keep the mouse in sync with rendering
render.mouse = mouse;

Events.on(mouseConstraint, 'mousedown', function(event) {
  let mousePosition = event.mouse.position;
  console.log('mousedown at ' + mousePosition.x + ' ' + mousePosition.y);
  console.log('ball >',ball);
  Body.applyForce(ball,ball.position,{x : 0.014, y : -0.04})
});