rd_render_loop.dart

/// This class shows how to implement a RenderLoop that pauses whenever
/// there's nothing going on.
/// It deliberately only treats one stage (Rd.STAGE) because that's how
/// the underlying framework works, but could easily be changed to support
/// several stages - see the super class.
class RdRenderLoop extends RenderLoop {

  bool _invalidate = false;
  num _currentTime = 0.0;

  EnterFrameEvent _enterFrameEvent = new EnterFrameEvent(0);
  ExitFrameEvent _exitFrameEvent = new ExitFrameEvent();
  RenderEvent _renderEvent = new RenderEvent();

  //----------------------------------------------------------------------------

  void invalidate() {
    _invalidate = true;
    super.invalidate();
  }

  //----------------------------------------------------------------------------

  void addStage(Stage stage) {

    if (stage.renderLoop != null) {
      stage.renderLoop.removeStage(stage);
    }

    stage.onMouseMove.capture((e) => _setRenderMode(stage));
    stage.onTouchMove.capture((e) => _setRenderMode(stage));
    stage.onMouseWheel.capture((e) => _setRenderMode(stage));

    super.addStage(stage);
  }

  void removeStage(Stage stage) {
    stage.onMouseMove.cancelSubscriptions();
    stage.onTouchMove.cancelSubscriptions();
    stage.onMouseWheel.cancelSubscriptions();

    super.removeStage(stage);
  }

  void advanceTime(num deltaTime) {
    _currentTime += deltaTime;

    if(Rd.JUGGLER.hasAnimatables){
      Rd.STAGE.renderMode = StageRenderMode.ONCE;
    }

    _enterFrameEvent.passedTime = deltaTime;
    _enterFrameEvent.dispatch();

    Rd.JUGGLER.advanceTime(deltaTime);

    if (_invalidate) {
      _invalidate = false;
      _renderEvent.dispatch();
    }

    Rd.STAGE.materialize(_currentTime, deltaTime);

    _exitFrameEvent.dispatch();
  }
}