Add tile visibility callback

src/three/TilesRenderer.js

@@ -74,6 +74,7 @@ export class TilesRenderer extends TilesRendererBase {
 		this.onLoadTileSet = null;
 		this.onLoadModel = null;
 		this.onDisposeModel = null;
+		this.onTileVisibilityChange = null;
 
 		const manager = new LoadingManager();
 		manager.setURLModifier( url => {
@@ -796,6 +797,11 @@ export class TilesRenderer extends TilesRendererBase {
 
 		}
 
+		if ( this.onTileVisibilityChange ) {
+
+			this.onTileVisibilityChange( scene, tile, visible );
+
+		}
 	}
 
 	setTileActive( tile, active ) {