KML Graphics Roadmap

[pjcozzi]

Derived Cesium graphics features for KML (#873).

Features

• Vector Data on Terrain: Vector Data on Terrain #2172
• Display conditions: Distance display conditions #758
• Improved camera flights: Camera Roadmap #1060 and Geocoder flights should take into account terrain #1670
• MSL terrain provider
• Line width in meters: Ability to specify line width in meters #1170 (might not need any new graphics code)
• Support for gx:drawOrder?
• Non-uniform model scale if anyone needs it.
• Handle -180 to 360 longitude

Memory usage

• Unused Polygon Vertices: Unused Polygon Vertices #1238
• Duplicate polyline vertices?: Investigate potential issues with duplicate polyline vertices #898
• Primitive normal compression: Add normal compression to Primitive #1628
• Billboard vertex compression: Vertex compression for billboards #419

Performance (both loading and rendering)

Loading Pipeline:

• Default granularity: Change default circle granularity #2173
• Optimized use of geometry by data sources, e.g., don't compute texture coordinates unless they are needed (perhaps this should be the default). Use EllipsoidSurfaceAppearance for polygons on the globe so we don't have to compute normals. Etc.
• Profile and analyze geometry pipeline, including (1) the algorithms, and (2) the use of web workers (Improve asynchronous Primitive creation #1487). Minimize memory usage throughout the pipeline.
• Investigate new triangulation library: Investigate new triangulation library #2074, randomChop() should not catch DeveloperError #1089
• Optimize polygon subdivision
• PolylinePipeline.wrapLongitude: PolylinePipeline.wrapLongitude performance #1197
• Giant bounding spheres: Primitive produces giant bounding spheres near the corners of the map #1539
• Performance ideas from Geometry and Appearances #766
• Investigate scratch arrays (see Improve extruded polygon and wall performance. #2329)

Rendering:

• Primitive.update: Optimize Primitive.update #1542
• Optimize setting uniforms: Optimize setting uniforms #649 and WebGL 2 and WebGL Extensions Roadmap #797 (Uniform buffer objects)
• Explore different bounding volumes?
• Fog?

Bugs

• Transparent billboards: Transparent billboards/points not working as expected. #2130
• Large polygons: Large polygons do not triangulate #620 (and circles: Large filled circles fill the opposite side. #998)
• Polygons perpendicular to the earth KML renders incorrectly - vertical polygons #3349

Related Features

• Declutter (Declutter roadmap #1097) and Scale labels based on distance (Scale labels based on distance #1075)
• Dynamic Buffers: Dynamic Buffers #932

[pjcozzi]

@mramato between what Cesium does now and what we listed above, are we missing any feature or performance/memory needs for KML?

[pjcozzi]

@mramato are we missing any feature or performance/memory needs for KML?

[mramato]

gx:latLonQuad is going to require support for trapezoidal texture projection, not sure where that fits in on the G&A pipeline.

PhotoOverlay requires quite a bit of work and probably warrants further investigation with its own issue and roadmap when the time comes.

[ggetz]

MSL height conversion was requested in https://community.cesium.com/t/cesium-ion-vs-google-earth-google-photorealistic/27819/9.