Snap 3D bridge lines to points on other sketch planes (#229)

* Snap 3D bridge drawing to points on visible sketch planes

* Keep cross-sketch point picks out of sketch tools

`pick()` returned every visible sketch's points while 3D drawing was on,
so `sketch_point_at` and the sketch tools could take another sketch's
point as an active-sketch local point plus id (flattening it or making a
bad coincident reference). `pick()` is local again; the bridge snap uses
`pick_3d` explicitly and hover mirrors it for feedback. `sketch_point_at`
also ignores foreign points defensively.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* test(sketch3d): check local point scope with a sketch tool active

Main's Project preselection fix now offers other sketches' points to idle
selection, so assert the local scope where it still applies.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* style: rustfmt

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: bherbruck <brennen.herbruck@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/sketch3d.rs

@@ -14,7 +14,7 @@ use solvecraft_engine::geom::{Vec2, Vec3};
 use crate::SolveApp;
 use crate::theme::Tokens;
 use crate::tools::Tool;
-use crate::viewport::{Hit, Proj, pick};
+use crate::viewport::{Hit, Proj, pick_3d};
 
 thread_local! {
     /// Points of the curve being drawn in 3D (with the tool they belong to).
@@ -40,6 +40,11 @@ fn takes(cmd: &str) -> bool {
     matches!(cmd, "sketch.line" | "sketch.spline.fit_point" | "sketch.point")
 }
 
+/// Only 3D point-placing tools broaden sketch-point picking; ordinary selection stays local.
+pub fn drawing(app: &SolveApp) -> bool {
+    active(app) && app.tool.as_ref().is_some_and(|tool| takes(tool.cmd))
+}
+
 /// Points drawn in 3D: (wire id, fit index, point).
 fn drawn_points(app: &SolveApp) -> Vec<(String, usize, Vec3)> {
     let st = app.session.world_state();
@@ -69,9 +74,13 @@ pub fn point_at(app: &SolveApp, proj: &Proj, pos: Pos2) -> Option<(Vec3, &'stati
     let st = app.session.world_state();
     let ss = app.session.active_sketch.and_then(|s| st.sketch(s))?;
     let (o, d) = proj.ray(pos);
-    for h in pick(app, proj, pos) {
+    for h in pick_3d(app, proj, pos) {
         match h {
-            Hit::SketchPoint { at, .. } => return Some((ss.plane.to_world(at), "Pt")),
+            Hit::SketchPoint { sketch, at, .. } => {
+                if let Some(source) = st.sketch(sketch) {
+                    return Some((source.plane.to_world(at), "Pt"));
+                }
+            }
             Hit::Vertex { point, .. } => return Some((point, "Vertex")),
             Hit::Edge { body, index, .. } => {
                 let ws = app.session.world_state();

crates/ui-egui/src/sketch3d_frame_ui_tests.rs

@@ -3,6 +3,128 @@
 use serde_json::json;
 use solvecraft_engine::geom::Vec3;
 
+#[test]
+fn bridge_line_snaps_to_points_on_two_visible_sketch_planes() {
+    let mut h = crate::scenario::Harness::new();
+    for (name, offset, point) in [("Lower", 10, [10, 20]), ("Upper", 40, [30, 35])] {
+        h.app.run("sketch.create", json!({"plane":{"origin":[0,0,offset],"x_dir":[1,0,0],"y_dir":[0,1,0]},"name":name})).unwrap();
+        h.app.run("sketch.point", json!({"point":point})).unwrap();
+        h.app.run("sketch.finish", json!({})).unwrap();
+    }
+    let bridge = h.app.run("sketch.create", json!({"plane":"XY","name":"Bridge"})).unwrap()["sketch"].as_u64().unwrap();
+    h.app.run("sketch.options", json!({"sketch_3d":true})).unwrap();
+    h.app.ui.show_origin = false;
+    h.call("ui.view", json!({"view":"home"}));
+    h.call("ui.view", json!({"view":"fit"}));
+    h.frames(3);
+    h.app.start("sketch.line");
+    h.frames(3);
+    // Idle selection offers other sketches' points for Project preselection; a sketch tool's
+    // ordinary pick stays local, and only the 3D bridge snap (`pick_3d`) reaches across.
+    let [x, y] = h.at(&json!({"world":[10,20,10]})).unwrap();
+    let proj = crate::viewport::projection(&h.app, h.app.viewport.rect.unwrap());
+    assert!(
+        crate::viewport::pick(&h.app, &proj, egui::pos2(x as f32, y as f32))
+            .iter()
+            .all(|hit| { !matches!(hit, crate::viewport::Hit::SketchPoint { sketch, .. } if *sketch != bridge) }),
+        "a sketch tool's ordinary pick must keep its local sketch-point scope"
+    );
+    for p in [[10, 20, 10], [30, 35, 40]] {
+        let [x, y] = h.at(&json!({"world":p})).unwrap();
+        let proj = crate::viewport::projection(&h.app, h.app.viewport.rect.unwrap());
+        let picked = crate::sketch3d::point_at(&h.app, &proj, egui::pos2(x as f32, y as f32)).unwrap().0;
+        assert!(picked.dist(Vec3::new(p[0] as f64, p[1] as f64, p[2] as f64)) < 1e-6, "{picked:?}");
+        h.step(&json!({"click":{"world":p}})).unwrap();
+    }
+    h.step(&json!({"key":"Escape"})).unwrap();
+    h.step(&json!({"key":"Escape"})).unwrap();
+    let state = h.app.session.world_state();
+    let wire = state.sketch(bridge).unwrap().sketch.wires.first().unwrap();
+    assert!(wire.fit[0].dist(Vec3::new(10.0, 20.0, 10.0)) < 1e-6);
+    assert!(wire.fit[1].dist(Vec3::new(30.0, 35.0, 40.0)) < 1e-6);
+    h.app.run("edit.undo", json!({})).unwrap();
+    assert!(h.app.session.world_state().sketch(bridge).unwrap().sketch.wires.is_empty());
+    h.app.run("edit.redo", json!({})).unwrap();
+    assert_eq!(h.app.session.world_state().sketch(bridge).unwrap().sketch.wires[0].fit, wire.fit);
+}
+
+/// Another sketch's point and an active sketch on the same XY plane, so both lie under one cursor.
+fn coplanar_foreign_point() -> (crate::scenario::Harness, u64, u64) {
+    let mut h = crate::scenario::Harness::new();
+    let other = h.app.run("sketch.create", json!({"plane":"XY","name":"Other"})).unwrap()["sketch"].as_u64().unwrap();
+    h.app.run("sketch.point", json!({"point":[10,20]})).unwrap();
+    h.app.run("sketch.finish", json!({})).unwrap();
+    let active = h.app.run("sketch.create", json!({"plane":"XY","name":"Active"})).unwrap()["sketch"].as_u64().unwrap();
+    h.app.ui.show_origin = false;
+    h.call("ui.view", json!({"view":"home"}));
+    h.call("ui.view", json!({"view":"fit"}));
+    h.frames(3);
+    (h, other, active)
+}
+
+#[test]
+fn sketch_tools_never_pick_another_sketchs_point() {
+    // Both in plain 2D sketching and while 3D drawing is on (the bridge snap's mode), the
+    // sketch-tool pick path must not return a foreign point as a local point plus id.
+    for sketch_3d in [false, true] {
+        let (mut h, other, active) = coplanar_foreign_point();
+        h.app.run("sketch.options", json!({"sketch_3d":sketch_3d})).unwrap();
+        h.app.start("sketch.line");
+        h.frames(3);
+        assert_eq!(crate::sketch3d::drawing(&h.app), sketch_3d);
+        let [x, y] = h.at(&json!({"world":[10,20,0]})).unwrap();
+        let pos = egui::pos2(x as f32, y as f32);
+        let proj = crate::viewport::projection(&h.app, h.app.viewport.rect.unwrap());
+        let hits = crate::viewport::pick(&h.app, &proj, pos);
+        assert!(
+            !hits.iter().any(|hit| matches!(hit, crate::viewport::Hit::SketchPoint { sketch, .. } if *sketch == other)),
+            "sketch_3d={sketch_3d}: pick leaked a point of sketch {other}: {hits:?}"
+        );
+        let (at, id) = crate::viewport::sketch_point_at(&h.app, &proj, pos).unwrap();
+        assert!(id.is_none(), "sketch_3d={sketch_3d}: snapped to foreign point id {id:?}");
+        assert!(at.dist(solvecraft_engine::geom::Vec2::new(10.0, 20.0)) < 0.5, "{at:?}");
+        if !sketch_3d {
+            let before = h.app.session.world_state().sketch(other).unwrap().sketch.clone();
+            // A real 2D line click there creates nothing tied to the other sketch's point.
+            h.step(&json!({"click":{"world":[10,20,0]}})).unwrap();
+            h.step(&json!({"click":{"world":[40,5,0]}})).unwrap();
+            h.step(&json!({"key":"Escape"})).unwrap();
+            let state = h.app.session.world_state();
+            let own = &state.sketch(active).unwrap().sketch;
+            assert!(!own.curves.is_empty(), "line was drawn");
+            assert_eq!(state.sketch(other).unwrap().sketch, before, "other sketch untouched");
+        }
+    }
+}
+
+#[test]
+fn bridge_snap_still_sees_other_sketch_points() {
+    let (mut h, other, _) = coplanar_foreign_point();
+    h.app.run("sketch.options", json!({"sketch_3d":true})).unwrap();
+    h.app.start("sketch.line");
+    h.frames(3);
+    let [x, y] = h.at(&json!({"world":[10,20,0]})).unwrap();
+    let pos = egui::pos2(x as f32, y as f32);
+    let proj = crate::viewport::projection(&h.app, h.app.viewport.rect.unwrap());
+    assert!(
+        crate::viewport::pick_3d(&h.app, &proj, pos)
+            .iter()
+            .any(|hit| matches!(hit, crate::viewport::Hit::SketchPoint { sketch, .. } if *sketch == other)),
+        "the 3D bridge pick offers the other sketch's point"
+    );
+    let (snapped, kind) = crate::sketch3d::point_at(&h.app, &proj, pos).unwrap();
+    assert_eq!(kind, "Pt");
+    assert!(snapped.dist(Vec3::new(10.0, 20.0, 0.0)) < 1e-6, "{snapped:?}");
+    // Hover highlights the snap target the click will use.
+    h.step(&json!({"move":{"world":[10,20,0]}})).unwrap();
+    h.frames(2);
+    assert!(
+        matches!(&h.app.viewport.hover, Some(crate::viewport::Hit::SketchPoint { sketch, .. }) if *sketch == other),
+        "{:?}",
+        h.app.viewport.hover
+    );
+}
+
 #[test]
 fn second_occurrence_drawn_wire_fit_picks_and_world_triad_drag_stay_aligned() {
     let mut h = crate::scenario::Harness::new();

crates/ui-egui/src/viewport.rs

@@ -682,6 +682,7 @@ fn pick_cached(app: &mut SolveApp, proj: &Proj, pos: Pos2) -> Vec<Hit> {
     app.session.revision.hash(&mut h);
     (std::sync::Arc::as_ptr(&app.session.world_state()) as usize).hash(&mut h);
     app.session.active_sketch.hash(&mut h);
+    crate::sketch3d::drawing(app).hash(&mut h);
     app.dialog.as_ref().and_then(|d| d.active_input()).map(|i| i.accept).hash(&mut h);
     app.session.visibility.hidden_bodies.hash(&mut h);
     app.session.visibility.hidden_occurrences.hash(&mut h);
@@ -694,21 +695,37 @@ fn pick_cached(app: &mut SolveApp, proj: &Proj, pos: Pos2) -> Vec<Hit> {
     {
         return hits.clone();
     }
-    let hits = pick(app, proj, pos);
+    // Hover feedback mirrors what a 3D bridge click will snap to; clicks still go through `pick`.
+    let hits = pick_with_sketch_points(app, proj, pos, crate::sketch3d::drawing(app));
     app.viewport.last_pick = Some((key, hits.clone()));
     hits
 }
 
+/// What is under `pos`. Sketch points come from the active sketch only (from every shown sketch
+/// while a dialog input takes points, while idle, or while projecting), so sketch tools never get
+/// another sketch's local point and id. The 3D bridge snap asks for cross-sketch points explicitly with [`pick_3d`].
 pub fn pick(app: &SolveApp, proj: &Proj, pos: Pos2) -> Vec<Hit> {
+    pick_with_sketch_points(app, proj, pos, false)
+}
+
+/// Like [`pick`], but also returns points of every visible sketch: only for the 3D drawing snap,
+/// which converts them to world space through their own sketch's plane.
+pub fn pick_3d(app: &SolveApp, proj: &Proj, pos: Pos2) -> Vec<Hit> {
+    pick_with_sketch_points(app, proj, pos, true)
+}
+
+fn pick_with_sketch_points(app: &SolveApp, proj: &Proj, pos: Pos2, other_sketch_points: bool) -> Vec<Hit> {
     let s = &app.session;
     let st = s.world_state();
     let bounds = body_bounds(app, &st);
     let bound = |name: &str| bounds.iter().find(|(n, _)| n == name).map(|(_, b)| *b);
     let mut hits = Vec::new();
     let (o, d) = proj.ray(pos);
-    // Sketch points of the active sketch (of every shown sketch while a command takes points).
+    // Sketch points of the active sketch (of every shown sketch while a command takes points,
+    // while idle or projecting, and while 3D drawing snaps to points on other visible sketches).
     let wants_points = app.dialog.as_ref().and_then(|d| d.active_input()).is_some_and(|i| i.accept & crate::selection::POINTS != 0);
-    let external_points = wants_points || (app.dialog.is_none() && app.tool.as_ref().is_none_or(|tool| tool.cmd == "sketch.project"));
+    let external_points =
+        wants_points || other_sketch_points || (app.dialog.is_none() && app.tool.as_ref().is_none_or(|tool| tool.cmd == "sketch.project"));
     let point_sketches: Vec<u64> = if external_points { visible_sketches(app) } else { s.active_sketch.into_iter().collect() };
     let mut best: Option<(f32, Hit)> = None;
     for ss in point_sketches.iter().filter_map(|sid| st.sketch(*sid)) {