text: const initAsteroid = ({id, pos, vel}) => ({
    id,
    physics_data: {
      inertia: {
        pos: pos.map(Math.round), vel: vel.map(Math.round)
      },
      body: asteroidBody
    }
  })
  
  const loadLevel = levelData => {
    const level = Object.assign(levelData, {
      asteroids: levelData.asteroids.map(initAsteroid)
    })
    return {
      ship: shipBody,
      level,
      time: 0,
      time0: 0,
      end: false,
      input,
      cam: [0,15],
      started: false,
      finished: false,
    }
  }