TMS tileset overlays

[gkjohnson]

• calculate appropriate detail mapping to TMS level
  • use bound size? Geometric error to pixel size?
• add helper to request, load, lock, and release textures in a data set
• when parsing a tileset request all textures, then draw to target geometry texture.
  • use existing uvs if possible?
  • use canvas texture to avoid need for webglrenderer?
  • compose multiple textures together.
• release textures on tile dispose
• if image set data is more detailed than the geometry then split into 4 tiles.
  • Reuse qmesh split logic but split on calculated bounding box axis
  • dispose of virtual children when parent is disposed.

Reuse tile image data managers in image loader data sets. Use for qmesh, too?

[gkjohnson]

tiles.registerPlugin( new ImageOverlayPlugin( {
  overlays: [
    new TMSOverlay( url ),
    new XYZOverlay( url, options ),
  ],
} );

[gkjohnson]

Remaining work:

Quality

• Split geometry for higher resolution data when last layer is reached.
• Calculate level for ellipsoid geometry based on available pixel density (?? - this means that tile size will impact detail loaded? Applies to planar projection, as well).

Later

Performance & Preload

• *Account for memory usage in LRUCache somehow?
  • Tiles now have "n" more textures and therefore memory usage
  • Can account for loaded texture data, as well?
  • Can add a plugin callback for calculating size?
• *Integrate image tile downloads into the same download queue for tiles so they are prioritized with the rest of the downloads.
  • Add "fake" tile shape for the sake of sorting? Use a proxy?
• Increase / tune download queue size in tiles renderer & plugin
  • Right now the Cesium tile sets load much more quickly.
• Afford a more intelligent selection of tile mapping layer to tiles.
  • Can compute some implicit geometric error for the tiles.

Quality

• Add option for fading images in after they've loaded
• Add option for not showing a new layer until all images are loaded
• Add a custom priority queue function to ensure most relevant tiles are loaded ASAP
  • Load images for "visible", "in frustum" and "used" tiles first.
• Consider drawing lower-res versions of tiles if high-res versions aren't present to enable more dynamic updates? Ideally we could update child tiles when parent LoDs load but this is more complex.
• Handle planar projection
  • How to handle auto-unwrapped tiles? Possibly keep extra information denoting the original range? (related to #1156)(Figure out how to handle planar projection of lat / lon)
  • Add preload for tiles

Other

• Fix / understand Google Tiles root tiles issue (possibly due to latitude wrapping)
  • At longitude wrap boundary the values jump from nearly - PI to nearly PI across a single triangle.
  • Add support for cap geometry (lunar tile set, earth)
• Allow for mipmap generation option?
• Account for image overlay tiles in LRUCache memory estimation? How? They're shared? Store this separately per image source?
• Add support for load progress?
• Consider need for "needs render" or "needs update" events. Test with r3f?

[gkjohnson]

Get textures working on Google Photorealistic Tiles & lunar data

The lunar data contains tiles that wrap over the poles of the globe resulting in some odd uvs and artifacts.

Google tiles contains a similar, though smaller, cap:

Perhaps this can be addressed by affording some kind of wrapping logic at the poles.

[gkjohnson]

When rendering to the google earth data set we can suffer from some artifacts at UV seams:

• would be best to compose textures in post to avoid issues from uv retargeting
• or we can expand the uv bounds.

[gkjohnson]

Planar Mapping

tiles.registerPlugin( new ImageOverlayPlugin( {
  renderer,
  overlays: [ new XYZPlugin( {
    /* ... */

    // Texture is projected along the Z axis - origin is the corner
    // of the image. If not present frame is assumed to be ellipsoid.
    frame: new Matrix4(),
  } ),
} ) );

/* ... */

plugin.overlays[ 0 ].frame = new Matrix4();
plugin.needsUpdate = true;

// Regenerate all UVs, textures, ranges, etc on all overlays. Need to do so without disposing
// of all previously loaded textures if they're still needed. Can be smart and only update needed textures.

• Preload can only occur with regions and ellipsoid projection (skip if frame is provided)
  • eventually can project bounds into the local frame.
• Initial implementation is removing the overlay and all images, regenerating uvs, then re initializing.
  • eventually would be best to reuse any images that are needed. this may be one reason to allow for marking tiles but delaying the fetch?

[gkjohnson]

~Another error occurred - rotate around, then switch to open street maps:~

Also ran into "INSUFFICIENT_RESOURCES" (loading a lot of tiles and then switching back and forth a few times can cause this):

[gkjohnson]

Closing in favor of #1204, #1205, #1206