Introduce roundtrip-able Points3D archetype (py + rs) (#2774)

**Commit by commit!**

What the title says.

This is a pre-requisite to push `Points{2|3}D` all the way, because we
don't really have any sort of tests in place for the legacy Point2D
stuff, on the other hand nearly everything makes use of the old
`Point3D`.

### What

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested [demo.rerun.io](https://demo.rerun.io/pr/2774) (if
applicable)

- [PR Build Summary](https://build.rerun.io/pr/2774)
- [Docs preview](https://rerun.io/preview/pr%3Acmc%2Fpoints3d_arch/docs)
- [Examples
preview](https://rerun.io/preview/pr%3Acmc%2Fpoints3d_arch/examples)

crates/re_types/definitions/rerun/archetypes.fbs

@@ -1,4 +1,5 @@
 include "./archetypes/points2d.fbs";
+include "./archetypes/points3d.fbs";
 include "./archetypes/transform3d.fbs";
 
 include "./testing/archetypes/fuzzy.fbs";

crates/re_types/definitions/rerun/archetypes/points3d.fbs

@@ -0,0 +1,72 @@
+include "fbs/attributes.fbs";
+
+include "rerun/datatypes.fbs";
+include "rerun/components.fbs";
+
+namespace rerun.archetypes;
+
+// ---
+
+/// A 3D point cloud with positions and optional colors, radii, labels, etc.
+///
+/// \py Example
+/// \py -------
+/// \py
+/// \py ```python
+/// \py \include:../../../../../docs/code-examples/point3d_simple_v2.py
+/// \py ```
+///
+/// \rs ## Example
+/// \rs
+/// \rs ```ignore
+/// \rs \include:../../../../../docs/code-examples/point3d_simple_v2.rs
+/// \rs ```
+table Points3D (
+  "attr.rust.derive": "PartialEq",
+  order: 100
+) {
+  // --- Required ---
+
+  /// All the actual 3D points that make up the point cloud.
+  points: [rerun.components.Point3D] ("attr.rerun.component_required", order: 1000);
+
+  // --- Recommended ---
+
+  /// Optional radii for the points, effectively turning them into circles.
+  radii: [rerun.components.Radius] ("attr.rerun.component_recommended", nullable, order: 2000);
+
+  /// Optional colors for the points.
+  ///
+  /// \python The colors are interpreted as RGB or RGBA in sRGB gamma-space,
+  /// \python As either 0-1 floats or 0-255 integers, with separate alpha.
+  colors: [rerun.components.Color] ("attr.rerun.component_recommended", nullable, order: 2100);
+
+  // --- Optional ---
+
+  /// Optional text labels for the points.
+  labels: [rerun.components.Label] ("attr.rerun.component_optional", nullable, order: 3000);
+
+  /// An optional floating point value that specifies the 3D drawing order.
+  /// Objects with higher values are drawn on top of those with lower values.
+  ///
+  /// The default for 3D points is 30.0.
+  draw_order: rerun.components.DrawOrder ("attr.rerun.component_optional", nullable, order: 3100);
+
+  /// Optional class Ids for the points.
+  ///
+  /// The class ID provides colors and labels if not specified explicitly.
+  class_ids: [rerun.components.ClassId] ("attr.rerun.component_optional", nullable, order: 3200);
+
+  /// Optional keypoint IDs for the points, identifying them within a class.
+  ///
+  /// If keypoint IDs are passed in but no class IDs were specified, the class ID will
+  /// default to 0.
+  /// This is useful to identify points within a single classification (which is identified
+  /// with `class_id`).
+  /// E.g. the classification might be 'Person' and the keypoints refer to joints on a
+  /// detected skeleton.
+  keypoint_ids: [rerun.components.KeypointId] ("attr.rerun.component_optional", nullable, order: 3300);
+
+  /// Unique identifiers for each individual point in the batch.
+  instance_keys: [rerun.components.InstanceKey] ("attr.rerun.component_optional", nullable, order: 3400);
+}

crates/re_types/definitions/rerun/components.fbs

@@ -5,5 +5,6 @@ include "./components/instance_key.fbs";
 include "./components/keypoint_id.fbs";
 include "./components/label.fbs";
 include "./components/point2d.fbs";
+include "./components/point3d.fbs";
 include "./components/radius.fbs";
 include "./components/transform3d.fbs";

crates/re_types/definitions/rerun/components/point3d.fbs

@@ -0,0 +1,21 @@
+include "arrow/attributes.fbs";
+include "python/attributes.fbs";
+include "rust/attributes.fbs";
+
+include "rerun/datatypes.fbs";
+include "rerun/attributes.fbs";
+
+namespace rerun.components;
+
+// ---
+
+/// A point in 3D space.
+struct Point3D (
+  "attr.python.aliases": "npt.NDArray[np.float32], Sequence[float], Tuple[float, float, float]",
+  "attr.python.array_aliases": "npt.NDArray[np.float32], Sequence[float]",
+  "attr.rerun.legacy_fqname": "rerun.point3d",
+  "attr.rust.derive": "Default, Copy, PartialEq, PartialOrd",
+  order: 100
+) {
+  xy: rerun.datatypes.Point3D (order: 100);
+}

crates/re_types/definitions/rerun/datatypes.fbs

@@ -2,6 +2,7 @@ include "./datatypes/angle.fbs";
 include "./datatypes/mat3x3.fbs";
 include "./datatypes/mat4x4.fbs";
 include "./datatypes/point2d.fbs";
+include "./datatypes/point3d.fbs";
 include "./datatypes/quaternion.fbs";
 include "./datatypes/rotation3d.fbs";
 include "./datatypes/rotation_axis_angle.fbs";

crates/re_types/definitions/rerun/datatypes/point3d.fbs

@@ -0,0 +1,20 @@
+include "arrow/attributes.fbs";
+include "python/attributes.fbs";
+include "fbs/attributes.fbs";
+include "rust/attributes.fbs";
+
+namespace rerun.datatypes;
+
+// ---
+
+/// A point in 3D space.
+struct Point3D (
+  "attr.python.aliases": "Sequence[float]",
+  "attr.python.array_aliases": "npt.NDArray[Any], Sequence[npt.NDArray[Any]], Sequence[Tuple[float, float]], Sequence[float]",
+  "attr.rust.derive": "Default, Copy, PartialEq, PartialOrd",
+  order: 100
+) {
+  x: float (order: 100);
+  y: float (order: 200);
+  z: float (order: 300);
+}

crates/re_types/source_hash.txt

@@ -1,4 +1,4 @@
 # This is a sha256 hash for all direct and indirect dependencies of this crate's build script.
 # It can be safely removed at anytime to force the build script to run again.
 # Check out build.rs to see how it's computed.
-94f7feacba1a7d75fee69d10294c77e2f4539106e4906f3d58a5db776e11c4be
+173356986894caad5a2b01f9b985726839309968b8466a9f1e19401efe546b87

crates/re_types/src/archetypes/mod.rs

@@ -2,8 +2,10 @@
 
 mod fuzzy;
 mod points2d;
+mod points3d;
 mod transform3d;
 
 pub use self::fuzzy::AffixFuzzer1;
 pub use self::points2d::Points2D;
+pub use self::points3d::Points3D;
 pub use self::transform3d::Transform3D;