Add extensions and extras to 3D Tiles

[lilleyse]

CesiumGS/3d-tiles#8 adds extras and extensions properties to the top-level tileset.json, individual tiles, feature table, batch table, and other misc json objects. How do we want to expose this from the API?

To start, we should atleast add an extras getter/setter to Cesium3DTileset and Cesium3DTile.

[pjcozzi]

As discussed offline, let's push this until after spec work unless it is critical to getting the spec right...which I don't think it is in this case given this is just following glTF's lead.

[lilleyse]

I agree, the implementation can wait.

[apopiak]

I would be interested in using extensions. As extras seem to be equally powerful that would be my fallback, but not optimal for building something well-defined.
Use-case: including (just bare-bones) images in 3D-tiles data that are loaded based on the HLOD.

[lilleyse]

@apopiak you can start using them now. The extras/extensions API looks like:

tile.extras
tileset.extras
tileset.hasExtension

There isn't a great way to get extension data from the API since it usually needs to be implemented internally. But for your use case you could start by storing image uris in each tile's extras and then listening to the tileset.tileLoad and tileset.tileVisible events where your app would handle the logic for loading and displaying the images.

[apopiak]

Ok, cool, thanks for the info! Will use extras then.

…

On Thu, Dec 13, 2018 at 3:02 PM Sean Lilley ***@***.***> wrote: @apopiak <https://github.com/apopiak> you can start using them now. The extras/extensions API looks like: tile.extras <https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTile.html?classFilter=cesium3dtile#extras> tileset.extras <https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileset.html?classFilter=cesium3dtileset#extras> tileset.hasExtension <https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileset.html?classFilter=cesium3dtileset#hasExtension> There isn't a great way to get extension data from the API since it usually needs to be implemented internally. But for your use case you could start by storing image uris in each tile's extras and then listening to the tileset.tileLoad <https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileset.html?classFilter=cesium3dtileset#tileLoad> and tileset.tileVisible <https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileset.html?classFilter=cesium3dtileset#tileVisible> events where your app would handle the logic for loading and displaying the images. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#6490 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGoVYkklHGIPq2jus21WNBxVv4_R3AkQks5u4l3lgaJpZM4TiZGg> .