[iTowns-user] Unwanted culling when rotating globe

[Adrien Berthet]

I see the problem then ! You need to rewrite the culling function then. To do this, simply write globeLayer.culling = (node) => { ... }); in the appropriate place.

The current culling works with the camera position (cameraPosition), so you only need to find the correct vector to replace this. Also mind that the first bit of the function (super.culling) may need to be removed/replaced as it is using camera as well.

https://github.com/iTowns/itowns/blob/master/src/Core/Prefab/Globe/GlobeLayer.js#L110-L128

Hope it helps.

________________________________
De : Terek Campbell [terekc at gmail.com]
Envoyé : mercredi 7 août 2019 16:03
À : Adrien Berthet
Cc : itowns-user at lists.osgeo.org
Objet : Re: [iTowns-user] Unwanted culling when rotating globe

Thanks for the responses!

In my case I think I need the actual globe to rotate as I have a number of satellites orbiting the globe and in order to keep their correct location over time, the globe must rotate as well.

I have a toggle between ECI<https://en.wikipedia.org/wiki/Earth-centered_inertial> and ECEF<https://en.wikipedia.org/wiki/ECEF> coordinate frames. When zoomed out and having ECI selected I'd like to see the globe rotating along with the satellites around it.

Upon zooming the camera in past a certain threshold, the scene will switch to the ECEF frame so that you're able to actually see what you're zooming into rather than having the earth fly past beneath you.

I'm open to other solutions if you have them. Let me know if you have any thoughts!

~Terek Campbell


On Wed, Aug 7, 2019 at 3:02 AM Adrien Berthet <Adrien.Berthet at ign.fr<mailto:Adrien.Berthet at ign.fr>> wrote:
Thanks !

So what you got wrong is that you are moving the globe, when you should be moving the camera.

Here's a quick thing you can do for example, using the controls lookAtCoordinate method:
let target = view.controls.getLookAtCoordinate();
setInterval(() => {
    target.x = (target.x + 180+ 0.5) % 360 - 180;
    globe.controls.lookAtCoordinate({ coord: target }, false);
    globe.notifyChange();
}, 100);
More information here http://www.itowns-project.org/itowns/docs/#api/Controls/GlobeControls and here http://www.itowns-project.org/itowns/docs/#api/Controls/CameraUtils

________________________________
De : Terek Campbell [terekc at gmail.com<mailto:terekc at gmail.com>]
Envoyé : mercredi 7 août 2019 01:07
À : Adrien Berthet
Cc : itowns-user at lists.osgeo.org<mailto:itowns-user at lists.osgeo.org>
Objet : Re: [iTowns-user] Unwanted culling when rotating globe

Here's a bit larger snippet with most of my iTowns related code:

  private initGlobeView(sceneDiv) {
    const position = new Coordinates("WGS84", 2.351323, 48.856712, 25e6);

    this.view = new GlobeView(sceneDiv, position, {
      scene3D: this.scene,
      renderer: this.renderer
    });

    const globeLayer = this.view.getLayerById("globe");
    const globe = globeLayer.object3d;

    this.view.addFrameRequester(MAIN_LOOP_EVENTS.UPDATE_START, () => {
      globe.rotation.z = this.globals.getSceneRotation();
    });

    Fetcher.json("../../../assets/layers/JSONLayers/Ortho.json").then(config => this.addColorLayerFromConfig(config));
    Fetcher.json("../../../assets/layers/JSONLayers/WORLD_DTM.json").then(config => this.addElevationLayerFromConfig(config));
    Fetcher.json("../../../assets/layers/JSONLayers/IGN_MNT_HIGHRES.json").then(config => this.addElevationLayerFromConfig(config));
  }

I'll note that overwriting the culling function like so
    globeLayer.culling = () => {};
does resolve my problem, but then I'm losing out on culling altogether. I'd like it to still do the culling, just have it properly cull despite the rotating earth.

I think the problem is that worldToScaledEllipsoid in iTowns GlobeLayer.js is not being updated and thus in GlobeLayer.js's preUpdate function the cameraPosition variable isn't being set correctly, but that's just speculation. I don't quite understand how all the parts are working together yet.


~Terek Campbell


On Tue, Aug 6, 2019 at 1:01 AM Adrien Berthet <Adrien.Berthet at ign.fr<mailto:Adrien.Berthet at ign.fr>> wrote:
Hello Terek,

Could you share a more independent example ? I'm not sure what is the `globe` variable here, that's why it may cause some odd culling.

Thanks

Adrien
________________________________
De : ITowns-user [itowns-user-bounces at lists.osgeo.org<mailto:itowns-user-bounces at lists.osgeo.org>] de la part de Terek Campbell [terekc at gmail.com<mailto:terekc at gmail.com>]
Envoyé : lundi 5 août 2019 23:35
À : itowns-user at lists.osgeo.org<mailto:itowns-user at lists.osgeo.org>
Objet : [iTowns-user] Unwanted culling when rotating globe

Hey all,

I’m attempting to rotate the globe over time via the following code:

    this.view.addFrameRequester(MAIN_LOOP_EVENTS.BEFORE_CAMERA_UPDATE, () => {
      globe.rotation.z = this.globals.getTotalRotation();
      this.view.notifyChange();
    });

However, I’m seeing odd culling once it starts rotating as in the attached screenshot. How can I prevent this?

~Terek Campbell
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