Collect scene nodes recursively (#224)

* ✨ collect scene nodes recursively

* Rename nodes_in_scene to root_nodes_in_scene, add recursive_nodes_in_scene

Split the scene node query API into two explicit methods:

- root_nodes_in_scene: returns only the top-level nodes directly
  referenced by the scene (the original behavior)
- recursive_nodes_in_scene: returns all nodes including descendants
  in depth-first order

This fixes a bug where animations targeting child (parented) nodes
were silently skipped because only root nodes were collected.

Update call sites:
- Animator test now uses recursive_nodes_in_scene for correctness
- Example crate simplified by removing manual get_children helper

Co-authored-by: Andreas Streichardt <andreas@mop.koeln>

* fix cache

* use matrix.os instead of runner.os

* ensure .cargo exists on CI

* ensure .cargo exists on CI

* ensure .cargo exists on CI

* ensure .cargo exists on CI

---------

Co-authored-by: Andreas Streichardt <andreas@mop.koeln>

Author: schell

.github/workflows/push.yaml

@@ -35,7 +35,7 @@ jobs:
         with:
           path: ~/.cargo
           # THIS KEY MUST MATCH BELOW
-          key: cargo-cache-${{ env.CARGO_GPU_COMMITSH }}-${{ runner.os }}
+          key: cargo-cache-${{ env.CARGO_GPU_COMMITSH }}-${{ matrix.os }}
       - uses: moonrepo/setup-rust@v1
       - run: rustup default stable 
       - run: rustup update
@@ -65,19 +65,22 @@ jobs:
       RUST_LOG: debug
     steps:
       - uses: actions/checkout@v2
+      # Run moonrepo/setup-rust BEFORE restoring ~/.cargo cache, because
+      # moonrepo restores its own ~/.cargo cache which would overwrite
+      # the cargo-gpu binary installed by the install-cargo-gpu job.
+      - uses: moonrepo/setup-rust@v1
       - uses: actions/cache@v4
         with:
           path: ~/.cargo
           # THIS KEY MUST MATCH ABOVE
-          key: cargo-cache-${{ env.CARGO_GPU_COMMITSH }}-${{ runner.os }}
+          key: cargo-cache-${{ env.CARGO_GPU_COMMITSH }}-${{ matrix.os }}
       - uses: actions/cache@v4
         with:
           path: | 
               ${{ needs.install-cargo-gpu.outputs.cachepath-macOS }}
               ${{ needs.install-cargo-gpu.outputs.cachepath-Linux }}
               ${{ needs.install-cargo-gpu.outputs.cachepath-Windows }}
-          key: rust-gpu-cache-0-${{ runner.os }}
-      - uses: moonrepo/setup-rust@v1
+          key: rust-gpu-cache-0-${{ matrix.os }}
       - run: rustup install nightly
       - run: rustup component add --toolchain nightly rustfmt
       - run: cargo gpu show commitsh
@@ -96,7 +99,8 @@ jobs:
         with:
           path: ~/.cargo
           # THIS KEY MUST MATCH ABOVE
-          key: cargo-cache-${{ env.CARGO_GPU_COMMITSH }}-${{ runner.os }}
+          key: cargo-cache-${{ env.CARGO_GPU_COMMITSH }}-ubuntu-latest
+      - run: mkdir -p $HOME/.cargo/bin
       - uses: moonrepo/setup-rust@v1
       - run: rustup install nightly
       - run: rustup component add --toolchain nightly rustfmt
@@ -130,8 +134,8 @@ jobs:
       - uses: actions/cache@v4
         with:
           path: ~/.cargo
-          key: ${{ runner.os }}-test-cargo-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: ${{ runner.os }}-cargo-
+          key: ${{ matrix.os }}-test-cargo-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ${{ matrix.os }}-cargo-
 
       - name: Install linux deps 
         if: runner.os == 'Linux'
@@ -150,7 +154,7 @@ jobs:
       - uses: actions/upload-artifact@v4
         if: always()
         with:
-          name: test-output-${{ runner.os }}
+          name: test-output-${{ matrix.os }}
           path: test_output  
 
   ## WASM tests, commented out until we can get a proper headless browser on CI

crates/example/src/lib.rs

@@ -286,29 +286,8 @@ impl App {
 
         let scene = doc.default_scene.unwrap_or(0);
         log::info!("Displaying scene {scene}");
-        fn get_children(doc: &GltfDocument, n: usize) -> Vec<usize> {
-            let mut children = vec![];
-            if let Some(parent) = doc.nodes.get(n) {
-                children.extend(parent.children.iter().copied());
-                let descendants = parent
-                    .children
-                    .iter()
-                    .copied()
-                    .flat_map(|n| get_children(doc, n));
-                children.extend(descendants);
-            }
-            children
-        }
 
-        let nodes = doc.nodes_in_scene(scene).flat_map(|n| {
-            let mut all_nodes = vec![n];
-            for child_index in get_children(&doc, n.index) {
-                if let Some(child_node) = doc.nodes.get(child_index) {
-                    all_nodes.push(child_node);
-                }
-            }
-            all_nodes
-        });
+        let nodes = doc.recursive_nodes_in_scene(scene);
         log::trace!("  nodes:");
         for node in nodes {
             let tfrm = Mat4::from(node.global_transform());

crates/renderling/src/gltf.rs

@@ -1237,7 +1237,24 @@ where
         self.primitives.iter().flat_map(|(_, rs)| rs.iter())
     }
 
-    pub fn nodes_in_scene(&self, scene_index: usize) -> impl Iterator<Item = &GltfNode> {
+    fn collect_nodes_recursive<'a>(&'a self, node_index: usize, nodes: &mut Vec<&'a GltfNode>) {
+        if let Some(node) = self.nodes.get(node_index) {
+            nodes.push(node);
+            for child_index in node.children.iter() {
+                self.collect_nodes_recursive(*child_index, nodes);
+            }
+        }
+    }
+
+    /// Returns the root (top-level) nodes in the given scene.
+    ///
+    /// This roughly follows [`gltf::Scene::nodes`](https://docs.rs/gltf/latest/gltf/scene/struct.Scene.html#method.nodes),
+    /// returning only the nodes directly referenced by the scene — not
+    /// their children.
+    ///
+    /// Use [`recursive_nodes_in_scene`](Self::recursive_nodes_in_scene)
+    /// if you need all nodes (including descendants).
+    pub fn root_nodes_in_scene(&self, scene_index: usize) -> impl Iterator<Item = &GltfNode> {
         let scene = self.scenes.get(scene_index);
         let mut nodes = vec![];
         if let Some(indices) = scene {
@@ -1250,6 +1267,22 @@ where
         nodes.into_iter()
     }
 
+    /// Returns all nodes in the given scene, recursively including
+    /// children.
+    ///
+    /// Root nodes are visited first, followed by their descendants in
+    /// depth-first order.
+    pub fn recursive_nodes_in_scene(&self, scene_index: usize) -> impl Iterator<Item = &GltfNode> {
+        let scene = self.scenes.get(scene_index);
+        let mut nodes = vec![];
+        if let Some(indices) = scene {
+            for node_index in indices {
+                self.collect_nodes_recursive(*node_index, &mut nodes);
+            }
+        }
+        nodes.into_iter()
+    }
+
     /// Returns the bounding volume of this document, if possible.
     ///
     /// This function will return `None` if this document does not contain

crates/renderling/src/gltf/anime.rs

@@ -787,7 +787,7 @@ mod test {
             .unwrap();
 
         let nodes = doc
-            .nodes_in_scene(doc.default_scene.unwrap_or_default())
+            .recursive_nodes_in_scene(doc.default_scene.unwrap_or_default())
             .collect::<Vec<_>>();
 
         let mut animator = Animator::new(nodes, doc.animations.first().unwrap().clone());