Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Additions to Point Cloud spec #733

Merged
merged 3 commits into from
Feb 7, 2023
Merged

Additions to Point Cloud spec #733

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
39ad1f7
Add note about sRGB colors in pnts spec
j9liu Feb 3, 2023
7b364ca
Note sRGB -> linear RGB in migration guide
j9liu Feb 3, 2023
41a36ea
Require POINTS_LENGTH to be greater than zero
j9liu Feb 3, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion specification/TileFormats/PointCloud/README.adoc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -175,7 +175,7 @@ These semantics define global properties for all points.

| `POINTS_LENGTH`
| `uint32`
| The number of points to render. The length of each array value for a point semantic should be equal to this.
| The number of points to render. This must be greater than zero. The length of each array value for a point semantic should be equal to this.
| Yes.

| `RTC_CENTER`
Expand Down Expand Up @@ -246,6 +246,8 @@ Compressed attributes should be decompressed before any other transforms are app

If more than one color semantic is defined, the precedence order is `RGBA`, `RGB`, `RGB565`, then `CONSTANT_RGBA`. For example, if a tile's Feature Table contains both `RGBA` and `CONSTANT_RGBA` properties, the runtime would render with per-point colors using `RGBA`.

Point colors are defined in sRGB color space.

If no color semantics are defined, the runtime is free to color points using an application-specific default color.

In any case, xref:{url-specification-styling}README.adoc#styling-styling[3D Tiles Styling] may be used to change the final rendered color and other visual properties at runtime.
Expand Down
1 change: 1 addition & 0 deletions specification/TileFormats/glTF/MIGRATION.adoc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@ xref:{url-specification-tileformats-pointcloud}README.adoc#tileformats-pointclou
* https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Vendor/EXT_meshopt_compression[`EXT_meshopt_compression`] and https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_mesh_quantization[`KHR_mesh_quantization`] may be used for point cloud compression. link:https://github.com/CesiumGS/3d-tiles/tree/main/extensions/3DTILES_draco_point_compression/[`3DTILES_draco_point_compression`] is not directly supported in glTF because https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_draco_mesh_compression[`KHR_draco_mesh_compression`] only supports triangle meshes.
* Batch IDs and Batch Tables can be represented using https://github.com/CesiumGS/glTF/tree/3d-tiles-next/extensions/2.0/Vendor/EXT_mesh_features[`EXT_mesh_features`] and https://github.com/CesiumGS/glTF/tree/3d-tiles-next/extensions/2.0/Vendor/EXT_structural_metadata[`EXT_structural_metadata`].
* `CONSTANT_RGBA` is not directly supported in glTF, but can be achieved with materials or per-point colors.
* If `COLOR` or `CONSTANT_RGBA` are present, they should be converted from sRGB to linear RGB in the glTF.

.Point Clouds in 3D Tiles 1.0, and the corresponding representation in 3D Tiles 1.1
image::figures/migration-pnts.png[pnts]
Expand Down