getting-started-animation

MainActivity.kt

private val frameCallback = object : Choreographer.FrameCallback {
   private val startTime = System.nanoTime()
   override fun doFrame(currentTime: Long) {
       val seconds = (currentTime - startTime).toDouble() / 1_000_000_000
       choreographer.postFrameCallback(this)
       modelViewer.animator?.apply {
           if (animationCount > 0) {
               applyAnimation(0, seconds.toFloat())
           }
           updateBoneMatrices()
       }
       modelViewer.render(currentTime)
   }
}