Merge PR #2891

crates/engine/src/cmd/puppet.rs

@@ -7,7 +7,8 @@
 //!
 //! Pin positions are in effect space. A new pin is attached to the mesh under it: the click is
 //! mapped back through the current deformation to the rest mesh (its hidden rest position), and
-//! Position / Advanced pins get a Position keyframe at the current time, as in After Effects.
+//! Position / Advanced pins get a Position keyframe at the current time, as in After Effects. Off
+//! every mesh a pin starts a new mesh, unless its art already has one (#2865).
 
 use effectcraft_effects::puppet::{self, MeshOpts, PinKind};
 use effectcraft_effects::{Buf, Params};
@@ -62,6 +63,32 @@ fn layer_time(s: &Session, cid: ItemId, lid: LayerId, t: Tick) -> Result<Tick> {
     Ok(l.layer_time(t))
 }
 
+/// Whether a pin at `at` (effect space) goes on this mesh as `def` deforms it: on it or beside it.
+fn on_mesh(mesh: &puppet::Mesh, def: &[[f64; 2]], at: [f64; 2]) -> bool {
+    !mesh.tris.is_empty() && (puppet::contains(mesh, def, at) || def.iter().map(|v| (v[0] - at[0]).hypot(v[1] - at[1])).fold(f64::MAX, f64::min) < 12.0)
+}
+
+/// Whether a new mesh at `at` (effect space) would repeat a mesh of `params`: the art it would
+/// outline is that mesh's own, even if a deformation has carried the mesh off it (#2865).
+fn repeats_mesh(buf: &Buf, params: &Params, at: [f64; 2]) -> bool {
+    let (w, h) = (buf.img.width as usize, buf.img.height as usize);
+    let alpha: Vec<f32> = buf.img.data.iter().map(|p| p[3]).collect();
+    puppet::parse(params).iter().any(|m| {
+        let mut outline = puppet::mesh::outline(&alpha, w, h, buf.scale.max(1e-9), buf.offset, at, m.opts.expansion);
+        // As `triangulate` winds it.
+        if puppet::mesh::signed_area(&outline) < 0.0 {
+            outline.reverse();
+        }
+        puppet::mesh_for(buf, m).outline == outline
+    })
+}
+
+/// Whether `puppet.addPin` at `at` (effect space) places a pin on a layer with a Puppet effect.
+pub fn places_pin(s: &Session, cid: ItemId, lid: LayerId, at: [f64; 2], t: Tick) -> bool {
+    let Some((buf, params)) = find_puppet(s, cid, lid).and_then(|fu| puppet_eval(s, cid, lid, fu, t)) else { return true };
+    !repeats_mesh(&buf, &params, at) || puppet::overlay(&buf, &params).iter().any(|(_, mesh, def, _)| on_mesh(mesh, def, at))
+}
+
 fn add_pin(s: &mut Session, p: &Value) -> Result<Value> {
     let cmd = "puppet.addPin";
     let (cid, lid) = layer_p(s, p, cmd)?;
@@ -93,9 +120,7 @@ fn add_pin(s: &mut Session, p: &Value) -> Result<Value> {
             if want_mesh.is_some_and(|w| w != *uid) || mesh.tris.is_empty() {
                 continue;
             }
-            let inside = puppet::contains(mesh, def, at);
-            let near = def.iter().map(|v| (v[0] - at[0]).hypot(v[1] - at[1])).fold(f64::MAX, f64::min) < 12.0;
-            if inside || near || want_mesh.is_some() {
+            if on_mesh(mesh, def, at) || want_mesh.is_some() {
                 let rest = puppet::unmap(mesh, def, at);
                 // A moving pin holds its nearest mesh vertex at `position + (vertex - rest)`
                 // (puppet::solve). Choose the position that keeps that vertex where it is now, so
@@ -120,6 +145,9 @@ fn add_pin(s: &mut Session, p: &Value) -> Result<Value> {
         {
             return Err(bad(cmd, format!("no mesh {w}")));
         }
+        if target.is_none() && repeats_mesh(&buf, &params, at) {
+            return Ok(json!({"pin": null, "changed": false}));
+        }
     }
     let opts = MeshOpts {
         density: f_p(p, "density").unwrap_or(s.state.puppet.density),

crates/engine/src/tests/paint.rs

@@ -225,6 +225,71 @@ fn a_pin_added_to_a_bent_mesh_moves_nothing() {
     }
 }
 
+fn mesh_count(s: &mut Session, id: u64) -> usize {
+    s.execute("puppet.info", json!({"layer": id})).unwrap()["meshes"].as_array().unwrap().len()
+}
+
+/// #2865: where the deformed layer is empty a click makes nothing: no copy of the art it has moved
+/// off, no undo step, no error.
+#[test]
+fn a_pin_where_the_deformed_layer_is_empty_creates_nothing() {
+    let (mut s, id) = setup();
+    s.execute("puppet.addPin", json!({"layer": id, "position": [10, 30]})).unwrap();
+    s.execute("puppet.addPin", json!({"layer": id, "position": [90, 30]})).unwrap();
+    s.set_time(Tick::from_seconds_f64(1.0));
+    s.execute("puppet.movePin", json!({"layer": id, "pin": "Puppet Pin 1", "position": [10, 70]})).unwrap();
+    s.execute("puppet.movePin", json!({"layer": id, "pin": "Puppet Pin 2", "position": [90, 70]})).unwrap();
+    let (cid, t) = (s.active_comp_id().unwrap(), Tick::from_seconds_f64(1.0));
+    let before = s.render(cid, t, RenderOpts::default());
+    let revision = s.revision;
+    let lid = effectcraft_project::LayerId(id);
+    // The solid's top, which the pins have carried 40 px down; and well off it.
+    for at in [[50, 10], [300, 300]] {
+        assert!(!crate::commands::puppet::places_pin(&s, cid, lid, [at[0] as f64, at[1] as f64], t), "{at:?}");
+        let r = s.execute("puppet.addPin", json!({"layer": id, "position": at})).unwrap();
+        assert_eq!(r["pin"], Value::Null, "{at:?}");
+        assert_eq!(s.revision, revision, "{at:?} changed the project");
+    }
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (1, 2));
+    assert_eq!(s.render(cid, t, RenderOpts::default()), before);
+    // Whatever Expansion new meshes would now get, the art is the mesh's own.
+    s.state.puppet.expansion = 9.0;
+    assert_eq!(s.execute("puppet.addPin", json!({"layer": id, "position": [50, 10]})).unwrap()["pin"], Value::Null);
+    // On the deformed shape a pin still goes on the mesh.
+    assert!(crate::commands::puppet::places_pin(&s, cid, lid, [50.0, 70.0], t));
+    assert!(s.execute("puppet.addPin", json!({"layer": id, "position": [50, 70]})).unwrap()["pin"].is_u64());
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (1, 3));
+}
+
+/// #2865: separate art still gets its own mesh, also from a near miss in the gap beside it (a click
+/// off the art finds the art nearest it): only a repeat of a mesh is refused.
+#[test]
+fn separate_art_still_gets_its_own_mesh() {
+    let (mut s, id) = setup();
+    for x in [[0, 30], [60, 100]] {
+        s.execute("mask.new", json!({"layer": id, "vertices": [[x[0], 0], [x[1], 0], [x[1], 60], [x[0], 60]], "closed": true})).unwrap();
+    }
+    s.execute("puppet.addPin", json!({"layer": id, "position": [10, 30]})).unwrap();
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (1, 1));
+    // In the gap, nearer the right piece and past reach of the left piece's mesh.
+    s.execute("puppet.addPin", json!({"layer": id, "position": [46, 30]})).unwrap();
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (2, 2), "the near miss meshes the right piece");
+    s.undo();
+    s.execute("puppet.addPin", json!({"layer": id, "position": [80, 30]})).unwrap();
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (2, 2), "the right piece gets its own mesh");
+    s.execute("puppet.addPin", json!({"layer": id, "position": [80, 50]})).unwrap();
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (2, 3), "and the next pin goes on it");
+}
+
+/// `newMesh` asks for a new mesh wherever the click is, the art's own mesh or not.
+#[test]
+fn new_mesh_option_starts_a_mesh_on_meshed_art() {
+    let (mut s, id) = setup();
+    s.execute("puppet.addPin", json!({"layer": id, "position": [10, 30]})).unwrap();
+    s.execute("puppet.addPin", json!({"layer": id, "position": [50, 30], "newMesh": true})).unwrap();
+    assert_eq!((mesh_count(&mut s, id), pin_count(&s, id)), (2, 2));
+}
+
 #[test]
 fn puppet_pin_kinds_and_mesh_options() {
     let (mut s, id) = setup();