alpha.4 fixes

Author: tychedelia

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "processing"
-version = "0.0.9-alpha.4"
+version = "0.0.9-alpha.5"
 edition = "2024"
 autoexamples = false
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "processing_pyo3"
-version = "0.0.9-alpha.4"
+version = "0.0.9-alpha.5"
 edition = "2024"
 
 [lints]

crates/processing_pyo3/Cargo.toml

@@ -1300,6 +1300,7 @@ pub mod mewnala {
                     .end_draw()?;
 
                 loop {
+                    py.check_signals()?;
                     {
                         let mut graphics = get_graphics_mut(module)?
                             .ok_or_else(|| PyRuntimeError::new_err("call size() first"))?;
@@ -1320,6 +1321,8 @@ pub mod mewnala {
             let mut first_frame = true;
 
             loop {
+                // also catches Ctrl-C while paused, when no Python code runs
+                py.check_signals()?;
                 {
                     let mut graphics = get_graphics_mut(module)?
                         .ok_or_else(|| PyRuntimeError::new_err("call size() first"))?;
@@ -1390,6 +1393,17 @@ pub mod mewnala {
             }
 
             Ok(())
+        })
+        .or_else(|e: PyErr| {
+            // Ctrl-C quits the sketch like closing its window, rather than a
+            // traceback from wherever draw() happened to be
+            Python::attach(|py| {
+                if e.is_instance_of::<pyo3::exceptions::PyKeyboardInterrupt>(py) {
+                    Ok(())
+                } else {
+                    Err(e)
+                }
+            })
         });
 
         // tear down the app while the thread-local is still alive; the eager

crates/processing_pyo3/src/lib.rs

@@ -1001,6 +1001,8 @@ impl Particles {
         for (key, value) in kwargs.iter() {
             let name: String = key.extract()?;
             let attr_entity = self.resolve_attribute(&key)?;
+            particles_ensure_attribute(self.entity, attr_entity)
+                .map_err(|e| PyRuntimeError::new_err(format!("{e}")))?;
             let (_, fmt) = geometry_attribute_info(attr_entity)
                 .map_err(|e| PyRuntimeError::new_err(format!("{e}")))?;
             let fmt = AttributeFormat::from_inner(fmt);

crates/processing_pyo3/src/particles.rs

@@ -100,6 +100,9 @@ pub struct Particles {
     /// Ring-buffer write cursor; wraps at `capacity`.
     pub emit_head: u32,
     pub neighbor_lists: Option<NeighborLists>,
+    /// The mesh a system made from a `Geometry` came from. Attributes created
+    /// later start from its data when it has them, so only what's used is copied.
+    pub source_mesh: Option<Handle<Mesh>>,
 }
 
 /// The `neighbors` (up to `max` indices per particle) and `neighbor_count` attributes.
@@ -163,6 +166,7 @@ pub fn create(
             connectivity: None,
             emit_head: 0,
             neighbor_lists: None,
+            source_mesh: None,
         })
         .id();
     Ok(entity)
@@ -245,6 +249,7 @@ pub fn create_from_geometry(
             connectivity,
             emit_head: 0,
             neighbor_lists: None,
+            source_mesh: Some(geom.handle.clone()),
         })
         .id();
     Ok(entity)
@@ -434,6 +439,7 @@ pub fn materialize_attribute(
     mut commands: Commands,
     mut particles_q: Query<&mut Particles>,
     attributes: Query<&Attribute>,
+    meshes: Res<Assets<Mesh>>,
     mut shader_buffers: ResMut<Assets<ShaderBuffer>>,
     render_device: Res<RenderDevice>,
 ) -> Result<Entity> {
@@ -442,7 +448,7 @@ pub fn materialize_attribute(
         .map_err(|_| ProcessingError::InvalidEntity)?
         .clone();
 
-    let capacity = {
+    let (capacity, from_mesh) = {
         let particles = particles_q
             .get(particles_entity)
             .map_err(|_| ProcessingError::ParticlesNotFound)?;
@@ -477,7 +483,15 @@ pub fn materialize_attribute(
                 ))),
             };
         }
-        particles.capacity as usize
+        let capacity = particles.capacity as usize;
+        let from_mesh = particles
+            .source_mesh
+            .as_ref()
+            .and_then(|handle| meshes.get(handle))
+            .and_then(|mesh| mesh.attribute(attr.inner))
+            .and_then(|values| attribute_values_to_bytes(values, attr.format))
+            .filter(|bytes| bytes.len() == capacity * attr.format.byte_size());
+        (capacity, from_mesh)
     };
 
     let elem_size = attr.format.byte_size();
@@ -506,7 +520,11 @@ pub fn materialize_attribute(
         }
     };
 
-    let initial = tile_seed(&per_element, capacity);
+    // an explicit default wins over the mesh's data
+    let initial = match (&seed, from_mesh) {
+        (AttributeSeed::Declare(Some(_)), _) | (_, None) => tile_seed(&per_element, capacity),
+        (_, Some(bytes)) => bytes,
+    };
     let buffer_entity = make_buffer(&mut commands, &mut shader_buffers, &render_device, &initial);
     particles_q
         .get_mut(particles_entity)