Fix video loader spinner in 3D views (rerun-io#7544)

### What
* Follow-up to rerun-io#7541 
* Closes rerun-io#7543

<img width="2398" alt="image"
src="https://github.com/user-attachments/assets/6f86614b-5eae-4f6d-a982-18cb877eae5d">
(image via @Wumpf : Wasn't able to catch the spinner because it
disappeared right away)

Test:
```
pixi run -e examples python3 tests/python/release_checklist/check_video.py
```

https://rerun.io/viewer/pr/7544?url=https%3A%2F%2Fstatic.rerun.io%2Frrd%2F0.19.0-alpha.1%2Bdev%2Fdata_dca3624dd9631b0208ab10257ec9495903699237.rrd

### 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 the web demo (if applicable):
* Using examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/7544?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/7544?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!
* [x] If have noted any breaking changes to the log API in
`CHANGELOG.md` and the migration guide

- [PR Build Summary](https://build.rerun.io/pr/7544)
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

To run all checks from `main`, comment on the PR with `@rerun-bot
full-check`.

crates/viewer/re_renderer/src/video/decoder/web.rs

@@ -434,7 +434,7 @@ impl VideoDecoder {
 
     /// Reset the video decoder and discard all frames.
     fn reset(&mut self) -> Result<(), DecodingError> {
-        re_log::debug!("Resetting video decoder.");
+        re_log::trace!("Resetting video decoder.");
         if let Err(_err) = self.decoder.reset() {
             // At least on Firefox, it can happen that reset on a previous error fails.
             // In that case, start over completely and try again!

crates/viewer/re_space_view_spatial/src/ui.rs

@@ -272,14 +272,48 @@ pub fn create_labels(
 pub fn paint_loading_spinners(
     ui: &egui::Ui,
     ui_from_scene: egui::emath::RectTransform,
+    eye3d: &Eye,
     visualizers: &re_viewer_context::VisualizerCollection,
 ) {
+    use glam::Vec3Swizzles as _;
+    use glam::Vec4Swizzles as _;
+
+    let ui_from_world_3d = eye3d.ui_from_world(*ui_from_scene.to());
+
     for data in visualizers.iter_visualizer_data::<SpatialViewVisualizerData>() {
-        for &rect_in_scene in &data.loading_rects {
-            let rect_in_ui = ui_from_scene.transform_rect(rect_in_scene);
+        for &crate::visualizers::LoadingSpinner {
+            center,
+            half_extent_u,
+            half_extent_v,
+        } in &data.loading_spinners
+        {
+            // Transform to ui coordinates:
+            let center_unprojected = ui_from_world_3d * center.extend(1.0);
+            if center_unprojected.w < 0.0 {
+                continue; // behind camera eye
+            }
+            let center_in_scene: glam::Vec2 = center_unprojected.xy() / center_unprojected.w;
+
+            let mut radius_in_scene = f32::INFINITY;
+
+            // Estimate the radius so we are unlikely to exceed the projected box:
+            for radius_vec in [half_extent_u, -half_extent_u, half_extent_v, -half_extent_v] {
+                let axis_radius = center_in_scene
+                    .distance(ui_from_world_3d.project_point3(center + radius_vec).xy());
+                radius_in_scene = radius_in_scene.min(axis_radius);
+            }
+
+            radius_in_scene *= 0.75; // Shrink a bit
+
+            let max_radius = 0.5 * ui_from_scene.from().size().min_elem();
+            radius_in_scene = radius_in_scene.min(max_radius);
+
+            let rect = egui::Rect::from_center_size(
+                egui::pos2(center_in_scene.x, center_in_scene.y),
+                egui::Vec2::splat(2.0 * radius_in_scene),
+            );
 
-            // Shrink slightly:
-            let rect = egui::Rect::from_center_size(rect_in_ui.center(), 0.75 * rect_in_ui.size());
+            let rect = ui_from_scene.transform_rect(rect);
 
             egui::Spinner::new().paint_at(ui, rect);
         }

crates/viewer/re_space_view_spatial/src/ui_2d.rs

@@ -287,7 +287,7 @@ impl SpatialSpaceView2D {
         }
 
         // Add egui-rendered spinners/loaders on top of re_renderer content:
-        crate::ui::paint_loading_spinners(ui, ui_from_scene, &system_output.view_systems);
+        crate::ui::paint_loading_spinners(ui, ui_from_scene, &eye, &system_output.view_systems);
 
         // Add egui-rendered labels on top of everything else:
         painter.extend(label_shapes);

crates/viewer/re_space_view_spatial/src/ui_3d.rs

@@ -691,6 +691,7 @@ impl SpatialSpaceView3D {
         crate::ui::paint_loading_spinners(
             ui,
             RectTransform::from_to(ui_rect, ui_rect),
+            &eye,
             &system_output.view_systems,
         );
 

crates/viewer/re_space_view_spatial/src/visualizers/mod.rs

@@ -28,6 +28,20 @@ pub use utilities::{
     UiLabel, UiLabelTarget,
 };
 
+/// Shows a loading animation in a spatial view.
+///
+/// Represents a 2D rectangle, oriented somewhere in scene coordinates.
+#[derive(Clone, Copy, Debug)]
+pub struct LoadingSpinner {
+    pub center: glam::Vec3,
+
+    /// The "radius" along one local axis.
+    pub half_extent_u: glam::Vec3,
+
+    /// The "radius" along the other local axis.
+    pub half_extent_v: glam::Vec3,
+}
+
 // ---
 
 use ahash::HashMap;

crates/viewer/re_space_view_spatial/src/visualizers/utilities/spatial_view_visualizer.rs

@@ -1,14 +1,14 @@
 use re_log_types::EntityPathHash;
 
 use super::UiLabel;
-use crate::{view_kind::SpatialSpaceViewKind, PickableTexturedRect};
+use crate::{view_kind::SpatialSpaceViewKind, visualizers::LoadingSpinner, PickableTexturedRect};
 
 /// Common data struct for all spatial scene elements.
 ///
 /// Each spatial scene element is expected to fill an instance of this struct with its data.
 pub struct SpatialViewVisualizerData {
     /// Loading icons/spinners shown using egui, in world/scene coordinates.
-    pub loading_rects: Vec<egui::Rect>,
+    pub loading_spinners: Vec<LoadingSpinner>,
 
     /// Labels that should be shown using egui.
     pub ui_labels: Vec<UiLabel>,
@@ -26,7 +26,7 @@ pub struct SpatialViewVisualizerData {
 impl SpatialViewVisualizerData {
     pub fn new(preferred_view_kind: Option<SpatialSpaceViewKind>) -> Self {
         Self {
-            loading_rects: Default::default(),
+            loading_spinners: Default::default(),
             ui_labels: Default::default(),
             bounding_boxes: Default::default(),
             pickable_rects: Default::default(),

crates/viewer/re_space_view_spatial/src/visualizers/videos.rs

@@ -25,7 +25,7 @@ use crate::{
     contexts::SpatialSceneEntityContext,
     ui::SpatialSpaceViewState,
     view_kind::SpatialSpaceViewKind,
-    visualizers::{entity_iterator, filter_visualizable_2d_entities},
+    visualizers::{entity_iterator, filter_visualizable_2d_entities, LoadingSpinner},
     PickableRectSourceData, PickableTexturedRect, SpatialSpaceView2D,
 };
 
@@ -207,14 +207,11 @@ impl VideoFrameReferenceVisualizer {
                             VideoFrameTexture::Ready(texture) => texture,
                             VideoFrameTexture::Pending(placeholder) => {
                                 // Show loading rectangle:
-                                let min = top_left_corner_position;
-                                let max = top_left_corner_position + extent_u + extent_v;
-                                let center = 0.5 * (min + max);
-                                let diameter = (max - min).truncate().abs().min_element();
-                                self.data.loading_rects.push(egui::Rect::from_center_size(
-                                    egui::pos2(center.x, center.y),
-                                    egui::Vec2::splat(diameter),
-                                ));
+                                self.data.loading_spinners.push(LoadingSpinner {
+                                    center: top_left_corner_position + 0.5 * (extent_u + extent_v),
+                                    half_extent_u: 0.5 * extent_u,
+                                    half_extent_v: 0.5 * extent_v,
+                                });
 
                                 // Keep polling for the decoded result:
                                 ctx.viewer_ctx.egui_ctx.request_repaint();

tests/assets/download_test_assets.py

@@ -2,7 +2,7 @@
 Downloads test assets used by tests.
 
 Usage:
-    pixi run python ./tests/assets/download_assets.py
+    pixi run python tests/assets/download_test_assets.py
 """
 
 from __future__ import annotations

tests/python/release_checklist/README.md

@@ -1,7 +1,6 @@
 ![Rerun.io](https://user-images.githubusercontent.com/1148717/218142418-1d320929-6b7a-486e-8277-fbeef2432529.png)
 
 # Interactive release checklist
-
 Welcome to the release checklist.
 
 _**⚠ Make sure to clean your blueprints if you want to start from a clean slate ⚠**_
@@ -10,8 +9,12 @@ _**⚠ Make sure to clean your blueprints if you want to start from a clean slat
 pixi run rerun reset
 ```
 
-### When releasing
+Run the testlist with:
+```
+pixi run -e examples python tests/python/release_checklist/main.py
+```
 
+### When releasing
 Each check comes in the form a recording that contains:
 1. a markdown document specifying the user actions to be tested, and
 2. the actual data required to test these actions.
@@ -23,8 +26,6 @@ If you've closed all of them, then things are in a releasable state.
 
 
 ### When developing
-
-
 Every time you make a PR to add a new feature or fix a bug that cannot be tested via automated means
 for whatever reason, take a moment to think: what actions did I take to manually test this, and should
 these actions be added as a new check in the checklist?

tests/python/release_checklist/check_video.py

@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+import os
+from argparse import Namespace
+from uuid import uuid4
+
+import rerun as rr
+
+README = """\
+# Video support
+This test only works in the browser!
+
+The video should show up both in 2D, 3D, and in the selection panel.
+
+When moving the time cursor, a "loading" spinner should show briefly, while the video is seeking.
+"""
+
+
+def run(args: Namespace) -> None:
+    rr.script_setup(args, f"{os.path.basename(__file__)}", recording_id=uuid4())
+
+    rr.log("readme", rr.TextDocument(README, media_type=rr.MediaType.MARKDOWN), timeless=True)
+
+    # Log video asset which is referred to by frame references.
+    video_path = os.path.dirname(__file__) + "/../../../tests/assets/video/Big_Buck_Bunny_1080_10s_av1.mp4"
+    video_asset = rr.AssetVideo(path=video_path)
+    rr.log("world/cam", video_asset, static=True)
+
+    # Send automatically determined video frame timestamps.
+    frame_timestamps_ns = video_asset.read_frame_timestamps_ns()
+    rr.send_columns(
+        "world/cam",
+        # Note timeline values don't have to be the same as the video timestamps.
+        times=[rr.TimeNanosColumn("video_time", frame_timestamps_ns)],
+        components=[rr.VideoFrameReference.indicator(), rr.components.VideoTimestamp.nanoseconds(frame_timestamps_ns)],
+    )
+
+    rr.log(
+        "world/cam",
+        rr.Transform3D(
+            translation=[10, 0, 0],
+        ),
+        static=True,  # Static, so it shows up in the "video_time" timeline!
+    )
+
+    rr.log(
+        "world/cam",
+        rr.Pinhole(
+            resolution=[1920, 1080],
+            focal_length=1920,
+        ),
+        static=True,  # Static, so it shows up in the "video_time" timeline!
+    )
+
+
+if __name__ == "__main__":
+    import argparse
+
+    parser = argparse.ArgumentParser(description="Interactive release checklist")
+    rr.script_add_args(parser)
+    args = parser.parse_args()
+    run(args)

tests/python/release_checklist/main.py

@@ -2,15 +2,17 @@
 from __future__ import annotations
 
 import argparse
+import glob
+import importlib
+import subprocess
+import sys
 from os.path import basename, dirname, isfile, join
+from pathlib import Path
 
 import rerun as rr
 
 
 def log_checks(args: argparse.Namespace) -> None:
-    import glob
-    import importlib
-
     modules = glob.glob(join(dirname(__file__), "*.py"))
     modules = [basename(f)[:-3] for f in modules if isfile(f) and basename(f).startswith("check_")]
 
@@ -29,6 +31,12 @@ def main() -> None:
     rr.script_add_args(parser)
     args = parser.parse_args()
 
+    # Download test assets:
+    download_test_assest_path = (
+        Path(__file__).parent.parent.parent.joinpath("assets/download_test_assets.py").absolute()
+    )
+    subprocess.run([sys.executable, download_test_assest_path])
+
     log_checks(args)
 
     # Log instructions last so that's what people see first.