[Solved, custom event] Infinite onviewchanged

Hi Klaus!

Changing hotspot.alpha via tweens in infinite animation causes infinite onviewchanged even if the view is not changing. This is due to WebGL rendering of hotspots. Please check why the engine reacts like this.

I have some code that uses the onviewchanged event and I'm finding that onviewchanged is firing infinitely even though the view is not changing.

Below I have provided a small test that points to the problem. Also I did not find any fundamental difference between onviewchanged and onviewchange in my tests, could you give some explanations. Yes, I read the documentation well.

<krpano version="1.22" onstart="showlog();">
		<style name="test_hotspot_style"
					 renderer="webgl"
					 blendmode="add"
					 url="hotspot.png"
					 enabled="false"
		/>
		<scene name="scene_test" title="Test Scene" onstart="blink();" autoload="true">
				<preview type="grid(cube,64,64,512,0x00FF00,0x000000,0x00FF00);" />
				<view hlookat="0.0" vlookat="0.0" fovtype="MFOV" fov="100" />
				<hotspot name="test_hotspot"
								 style="test_hotspot_style"
								 ath="0.0"
								 atv="0.0"
								 scale="1.0"
								 alpha="1.0"
								 bright="1.0"
				/>
		</scene>
		<events name="test_events" keep="true"
						onviewchanged="trace('onviewchanged triggered');"
		/>
		<action name="blink" scope="local">
				set(random_alpha, get(random));
				tween(hotspot[test_hotspot].alpha, get(random_alpha), 0.5, linear, blink();); <!-- alpha or scale or ... -->
		</action>
</krpano>

Is there any way to track changes directly to the view (hlookat, vlookat, fov, etc.) without using hacks? I couldn't think of anything other than tracking changes to each of them (hlookat, vlookat, fov, etc.)

Thanks guys! The new syntax is convenient. I want to write a plugin with support for older versions of krpano (1.21 and older). So I'll have to do it the old way

Quote from klaus.krpano

Hi,

here an example to extend krpano with a 'onlookchange' event that tracks only hlookat, vlookat and fov changes (could be extended with other view attributes too):

Code

<action type="js" autorun="onstart">

	var view = krpano.view;
	var attrs = ["hlookat", "vlookat", "fov"];
	var prevstate = {};
	
	attrs.forEach( function(attr){ prevstate[attr] = view[attr]; });

	krpano.events.addListener("onviewchanged", function()
	{
		var haschanged = false;
		
		attrs.forEach( function(attr)
		{
			if (prevstate[attr] != view[attr])
			{
				prevstate[attr] = view[attr];
				haschanged = true;
			}
		});
		
		if (haschanged)
		{
			krpano.events.dispatch("onlookchange");
		}
	});
	
</action>

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Best regards,
Klaus

Thank you Klaus!