<krpano>

	<!--
		webvr_autozoom.xml
		krpano 1.21
		
		https://krpano.com/plugins/xmlextensions/#webvr_autozoom

		A helper script for zooming in VR.
		
		After ~2 seconds staring at one point, the view slowly starts zooming-in.
		When looking around, the zooming-in stops and the view starts slowly zooming-out
		back to the normal view (the faster the looking-around the faster the zooming-out). 
	-->

	<events name="webvr_autozoom" keep="true"
	        onnewpano="webvr_autozoom_calc_maxzoom();"
	        webvr_onentervr="webvr_autozoom_start();"
	        webvr_onexitvr="webvr_autozoom_stop();"
	        />


	<!-- some settings -->
	<action name="webvr_autozoom_init" scope="private:webvr_autozoom" autorun="onstart">
		set(zoom_delay, 2.0);
		set(movement_tolerance, 0.01);
		set(zoom_speed, 1.0);
		set(max_zoom, 10);
	</action>


	<!-- calc maxzoom depending onthe current pano image -->
	<action name="webvr_autozoom_calc_maxzoom" scope="private:webvr_autozoom">
		set(maxwidth, get(global.image.hres));
		if(tolower(global.image.type) == 'cube',
			calc(maxwidth, maxwidth * Math.PI);
		  ,tolower(global.image.type) == 'flat',
			calc(maxwidth, maxwidth * 360 / 90);
		  ,
			calc(maxwidth, maxwidth * 360 / global.image.hfov);
		);
		calc(max_zoom, maxwidth / 4000);
	</action>


	<action name="webvr_autozoom_stop" scope="private:webvr_autozoom">
		clearinterval(webvr_autozoom);
	</action>


	<action name="webvr_autozoom_start" scope="private:webvr_autozoom">
		copy(last_tick, global.timertick);
		copy(last_movement_tick, last_tick);
		copy(last_view_hlookat, global.view.hlookat);
		copy(last_view_vlookat, global.view.vlookat);

		setinterval(webvr_autozoom, 0.1,
			copy(cur_tick, global.timertick);
			if(global.webvr.isenabled,
				getlooktodistance(move_distance, last_view_hlookat, last_view_vlookat);
				calc(movespeed, move_distance / (cur_tick-last_tick));

				calc(movement_tolerance, 0.01 / (global.webvr.zoom^0.5));
				if(movespeed GT movement_tolerance,
					copy(last_movement_tick, cur_tick);
					tween(zoom_speed, 1.0, 0);
					Math.pow(movespeed, 0.5);
				);

				if((cur_tick - last_movement_tick) GT (zoom_delay*1000),
					tween(zoom_speed, 1.04);
				);

				calc(new_zoom, global.webvr.zoom * (zoom_speed * (1.0 - movespeed)) );
				clamp(new_zoom, 1, get(max_zoom));
				tween(global.webvr.zoom, get(new_zoom), 0.1, linear);

				calc(global.webvr.friction, new_zoom GT 2.0 ? (new_zoom - 2.0) / 100.0 : 0);
			  ,
				copy(last_movement_tick, cur_tick);
			);
			copy(last_tick, cur_tick);
			copy(last_view_hlookat, global.view.hlookat);
			copy(last_view_vlookat, global.view.vlookat);
		);
	</action>

</krpano>