"Render on change" example enhanchement

[liberostelios]

The current example for not using a loop works, but it won't start loading the tiles unless something forces a second tilesRenderer.update(); to be called.

This can be improved by making needsRerender an integer with the number of times to re-render and starting with 2. So the example would be:

let needsRerender = 2;
const tilesRenderer = new TilesRenderer( './path/to/tileset.json' );
tilesRenderer.onLoadTileSet = () => needsRerender = 1;
tilesRenderer.onLoadModel = () => needsRerender = 1;

function renderLoop() {

	requestAnimationFrame( renderLoop );
	if ( needsRerender > 0) {
	
		needsRerender--;
		tilesRenderer.update();
		renderer.render( camera, scene );
	
	}

}
renderLoop();

There is also a typo on upadate().

[gkjohnson]

There is also a typo on upadate().

Heh, thanks :) fixed!

The current example for not using a loop works, but it won't start loading the tiles unless something forces a second tilesRenderer.update(); to be called.

Hmm I thought that's what #112 addressed? If this is true then I think it's a bug. Have you tracked down why? Is onLoadTileSet being fired? Here's what should be happening:

1. Initial update is called which triggers load of tileset.json
2. tileset.json finishes loading which fires onLoadTileSet setting the render flag
3. update is called again with triggers load of tile geometry.
4. tile geometry finishes loading which fires onLoadModel setting the render flag
5. repeat

[liberostelios]

2. tileset.json finishes loading which fires `onLoadTileSet` setting the render flag

3. update is called again with triggers load of tile geometry.

4. tile geometry finishes loading which fires `onLoadModel` setting the render flag

Actually, the example above was incorrect. This is the part that breaks. So the right code would be:

let needsRerender = 1;
const tilesRenderer = new TilesRenderer( './path/to/tileset.json' );
tilesRenderer.onLoadTileSet = () => needsRerender = 2;
tilesRenderer.onLoadModel = () => needsRerender = 1;

function renderLoop() {

	requestAnimationFrame( renderLoop );
	if ( needsRerender > 0) {
	
		needsRerender--;
		tilesRenderer.update();
		renderer.render( camera, scene );
	
	}

}
renderLoop();

Well, #112 solves the issue in the sense that you can now initiate the two calls after the tileset.json is downloaded (which, if big enough, could take a while). For some reason, though, two update() calls are required after the tileset is downloaded in order to initiate the first tile geometry download. At least that's for me.

[gkjohnson]

For some reason, though, two update() calls are required after the tileset is downloaded in order to initiate the first tile geometry download.

Hm I'm unable reproduce this. Here are the changes I'd made with logs to show when tilesets and models are loaded and the terrain updates correctly. Note that manipulating orbit controls will not rerender with this quick change:

https://github.com/NASA-AMMOS/3DTilesRendererJS/compare/load-callback-repro

Do you mind modifying the example page to show the problem?

[liberostelios]

That's interesting. We are using the library in project and we have to update twice. You can check the code here:

https://github.com/tudelft3d/3dbag-viewer/blob/feature/upgrade-3dtiles-lib/src/components/ThreeViewer.vue

Keep in mind, though, that this is using a fork which adds this modification:

liberostelios@91dbb3e

This is to force error calculation on empty tiles, as we discussed in #111. Could this be the problem?

[gkjohnson]

It's possible that the camera world matrix is not up date when tiles.update is called the first time because it's updated here rather than beforehand.

It's mentioned in the update docs that it needs to be updated beforehand but I've updated the example code so it's more clear. Let me know if that works!

[liberostelios]

I've moved camera.updateMatrixWorld() before tiles.update() and still get the same behaviour. That's weird. I guess for now I'll leave it like that, known that it's probably that has to do with our specific setup.

[gkjohnson]

Hm thats odd then 🤔 Without digging into the code further to debug I'm not sure if I can spot anything further. Would you be able to make a small repro with the example page? Maybe it's something to do with the particular tileset being used? Or maybe it is small change you've made?

[liberostelios]

Interestingly, it is the change that I made. I just checked without it and in that case it works with just one update call.

I am not sure I can track down what causes this, but maybe I should given #119.

[gkjohnson]

I'm gonna go ahead and close this if you don't mind because I'm unable to reproduce the issue. If it turns out this is a problem that can be reproduced in the example code then lets reopen and we can track it down!

[liberostelios]

That's a fair point. I don't think it's worth wasting more time on it.