Fix pinhole visualization not working with camera extrinsics & intrin…

…sics on the same path (#2568)

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### What

Our recent transform reform (as landed in 0.7) allows us to log pinhole
and transform on the same entity. By convention we first apply
transform3d then pinhole as-if transform3d was higher in the hierarchy.
This was already the case, but the displayed pinhole frustum was broken.

I used this to simplify the object hierarchy in both the rust and python
objectron. While doing so I noticed that Rust objectron didn't have the
half-box fix applied yet we had on the Python version.


![image](https://github.com/rerun-io/rerun/assets/1220815/e41c40eb-5ca6-4906-80c3-1a656f4cc0f8)


### 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 have tested https://demo.rerun.io/pr/2568 (if applicable)

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PR Build Summary: https://build.rerun.io/pr/2568

<!-- pr-link-docs:start -->
Docs preview: https://rerun.io/preview/3284fda/docs
Examples preview: https://rerun.io/preview/3284fda/examples
<!-- pr-link-docs:end -->

crates/re_space_view_spatial/src/scene/parts/cameras.rs

@@ -1,6 +1,6 @@
 use re_components::{
     coordinates::{Handedness, SignedAxis3},
-    Component, InstanceKey, Pinhole, ViewCoordinates,
+    Component, InstanceKey, Pinhole, Transform3D, ViewCoordinates,
 };
 use re_data_store::{EntityPath, EntityProperties};
 use re_renderer::renderer::LineStripFlags;
@@ -56,12 +56,14 @@ pub struct CamerasPart {
 }
 
 impl CamerasPart {
+    #[allow(clippy::too_many_arguments)]
     fn visit_instance(
         &mut self,
         scene_context: &SpatialSceneContext,
         ent_path: &EntityPath,
         props: &EntityProperties,
         pinhole: Pinhole,
+        transform_at_entity: Option<Transform3D>,
         view_coordinates: ViewCoordinates,
         entity_highlight: &SpaceViewOutlineMasks,
     ) {
@@ -70,13 +72,10 @@ impl CamerasPart {
         // The transform *at* this entity path already has the pinhole transformation we got passed in!
         // This makes sense, since if there's an image logged here one would expect that the transform applies.
         // We're however first interested in the rigid transform that led here, so query the parent transform.
-        //
-        // Note that currently a transform on an object can't have both a pinhole AND a rigid transform,
-        // which makes this rather well defined here.
         let parent_path = ent_path
             .parent()
             .expect("root path can't be part of scene query");
-        let Some(world_from_parent) = scene_context.transforms.reference_from_entity(&parent_path) else {
+        let Some(mut world_from_camera) = scene_context.transforms.reference_from_entity(&parent_path) else {
                 return;
             };
 
@@ -94,16 +93,24 @@ impl CamerasPart {
             return;
         }
 
+        // There's one wrinkle with using the parent transform though:
+        // The entity itself may have a 3D transform which (by convention!) we apply *before* the pinhole camera.
+        // Let's add that if it exists.
+        if let Some(transform_at_entity) = transform_at_entity {
+            world_from_camera =
+                world_from_camera * transform_at_entity.to_parent_from_child_transform();
+        }
+
         // If this transform is not representable an iso transform transform we can't display it yet.
         // This would happen if the camera is under another camera or under a transform with non-uniform scale.
-        let Some(world_from_camera) = macaw::IsoTransform::from_mat4(&world_from_parent.into()) else {
+        let Some(world_from_camera_iso) = macaw::IsoTransform::from_mat4(&world_from_camera.into()) else {
             return;
         };
 
         self.space_cameras.push(SpaceCamera3D {
             ent_path: ent_path.clone(),
             view_coordinates,
-            world_from_camera,
+            world_from_camera: world_from_camera_iso,
             pinhole: Some(pinhole),
             picture_plane_distance: frustum_length,
         });
@@ -160,7 +167,7 @@ impl CamerasPart {
         let mut line_builder = scene_context.shared_render_builders.lines();
         let mut batch = line_builder
             .batch("camera frustum")
-            .world_from_obj(world_from_parent)
+            .world_from_obj(world_from_camera)
             .outline_mask_ids(entity_highlight.overall)
             .picking_object_id(instance_layer_id.object);
         let lines = batch
@@ -212,6 +219,7 @@ impl ScenePart<SpatialSpaceView> for CamerasPart {
                     ent_path,
                     &props,
                     pinhole,
+                    store.query_latest_component::<Transform3D>(ent_path, &query),
                     view_coordinates,
                     entity_highlight,
                 );

examples/python/objectron/main.py

@@ -116,7 +116,7 @@ def log_ar_frames(samples: Iterable[SampleARFrame], seq: Sequence) -> None:
         rr.set_time_seconds("time", sample.timestamp)
         frame_times.append(sample.timestamp)
 
-        rr.log_image_file("world/camera/video", img_path=sample.image_path, img_format=rr.ImageFormat.JPEG)
+        rr.log_image_file("world/camera", img_path=sample.image_path, img_format=rr.ImageFormat.JPEG)
         log_camera(sample.frame.camera)
         log_point_cloud(sample.frame.raw_feature_points)
 
@@ -149,7 +149,7 @@ def log_camera(cam: ARCamera) -> None:
     )
     rr.log_view_coordinates("world/camera", xyz="RDF")  # X=Right, Y=Down, Z=Forward
     rr.log_pinhole(
-        "world/camera/video",
+        "world/camera",
         child_from_parent=intrinsics,
         width=w,
         height=h,
@@ -203,11 +203,11 @@ def log_frame_annotations(frame_times: list[float], frame_annotations: list[Fram
             keypoint_pos2s *= IMAGE_RESOLUTION
 
             if len(keypoint_pos2s) == 9:
-                log_projected_bbox(f"world/camera/video/estimates/box-{obj_ann.object_id}", keypoint_pos2s)
+                log_projected_bbox(f"world/camera/estimates/box-{obj_ann.object_id}", keypoint_pos2s)
             else:
                 for id, pos2 in zip(keypoint_ids, keypoint_pos2s):
                     rr.log_point(
-                        f"world/camera/video/estimates/box-{obj_ann.object_id}/{id}",
+                        f"world/camera/estimates/box-{obj_ann.object_id}/{id}",
                         pos2,
                         color=[130, 160, 250, 255],
                     )

examples/rust/objectron/src/main.rs

@@ -123,7 +123,7 @@ fn log_baseline_objects(
                 return None;
             }
 
-            let box3: Box3D = glam::Vec3::from_slice(&object.scale).into();
+            let box3: Box3D = (glam::Vec3::from_slice(&object.scale) * 0.5).into();
             let transform = {
                 let translation = glam::Vec3::from_slice(&object.translation);
                 // NOTE: the dataset is all row-major, transpose those matrices!
@@ -153,7 +153,7 @@ fn log_video_frame(rec_stream: &RecordingStream, ar_frame: &ArFrame) -> anyhow::
     let image_path = ar_frame.dir.join(format!("video/{}.jpg", ar_frame.index));
     let tensor = rerun::components::Tensor::from_jpeg_file(&image_path)?;
 
-    MsgSender::new("world/camera/video")
+    MsgSender::new("world/camera")
         .with_timepoint(ar_frame.timepoint.clone())
         .with_component(&[tensor])?
         .send(rec_stream)?;
@@ -198,7 +198,7 @@ fn log_ar_camera(
             rot,
         ))])?
         .send(rec_stream)?;
-    MsgSender::new("world/camera/video")
+    MsgSender::new("world/camera")
         .with_timepoint(timepoint)
         .with_component(&[Pinhole {
             image_from_cam: intrinsics.into(),
@@ -262,12 +262,9 @@ fn log_frame_annotations(
             })
             .unzip();
 
-        let mut msg = MsgSender::new(format!(
-            "world/camera/video/estimates/box-{}",
-            ann.object_id
-        ))
-        .with_timepoint(timepoint.clone())
-        .with_splat(ColorRGBA::from_rgb(130, 160, 250))?;
+        let mut msg = MsgSender::new(format!("world/camera/estimates/box-{}", ann.object_id))
+            .with_timepoint(timepoint.clone())
+            .with_splat(ColorRGBA::from_rgb(130, 160, 250))?;
 
         if points.len() == 9 {
             // Build the preprojected bounding box out of 2D line segments.