function inner_start()
	{
		//start playing once loaded the json
		if(that.autoplay)
			that.play();
		else if(!that.skip_play_button)
			that.showPlayDialog();
		//console.log("Scene playing");
		if(	that.loading )
			that.loading.visible = false;
		that._ondraw( true );
		setTimeout(function(){ that._ondraw( true ); },1000); //render a frame after some time to ensure loading
		if(window.onSceneReady)
			window.onSceneReady();
		window.postMessage("ready","*");
		if(window.top)
			window.top.postMessage("ready","*");
		if(on_complete)
			on_complete();
	}
Loads an scene and triggers start
@method loadScene
@param {String} url url to the JSON file containing all the scene info
@param {Function} on_complete callback trigged when the scene and the resources are loaded