Render R2: persist named render setups without re-evaluating geometry (#667)

render.settings.set saves validated named render setups (camera, output size, exposure, environment) as one undo step, and render.settings.get reads them back without applying a camera. When validated render settings are the only change, the engine keeps the evaluated model instead of rebuilding it. Setups are saved under design format 21; format-20 designs read as having none. Fixes #658; refs #620.

Contributed by @0xlillith.

Co-authored-by: lillith <35337584+0xlillith@users.noreply.github.com>

crates/engine/src/cmd/render/settings_tests.rs

@@ -0,0 +1,131 @@
+use super::*;
+
+fn save(s: &mut Session, patch: Value) {
+    s.execute("render.settings.set", &json!({"name":"Studio", "set":patch})).unwrap();
+}
+
+#[test]
+fn settings_history_preserves_geometry_cache_and_dirty_state() {
+    let mut s = Session::default();
+    let component = s.execute("component.create", &json!({"name":"Part"})).unwrap();
+    s.execute("solid.box", &json!({"length":10,"width":20,"height":5})).unwrap();
+    s.execute("component.activate", &json!({"component":0})).unwrap();
+    s.execute("occurrence.move", &json!({"occurrence":component["occurrence"],"translate":[30,0,0]})).unwrap();
+    s.mark_saved();
+    let model = s.model.state();
+    let world = s.world_state();
+    assert!(!Arc::ptr_eq(&model, &world), "exercise the prepared occurrence cache");
+    let mesh = model.bodies[0].mesh();
+    let undo = s.undo.len();
+    s.evaluations = 0;
+    save(&mut s, json!({"exposure_ev":2,"backend":"future-backend"}));
+    assert!(s.is_dirty());
+    assert_eq!(s.undo.len(), undo + 1);
+    let doc = s.doc.clone();
+    let revision = s.revision;
+    save(&mut s, json!({"exposure_ev":2}));
+    assert!(Arc::ptr_eq(&doc, &s.doc));
+    assert_eq!(s.revision, revision);
+    assert_eq!(s.undo.len(), undo + 1);
+    let restored = solidcraft_doc::Document::from_json(&s.doc.to_json()).unwrap();
+    assert_eq!(restored.render, s.doc.render);
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert!(!s.is_dirty());
+    s.execute("render.settings.get", &json!({})).unwrap();
+    assert_eq!(s.redo.len(), 1);
+    s.execute("edit.redo", &json!({})).unwrap();
+    let checkpoint = s.checkpoint();
+    save(&mut s, json!({"width":800}));
+    s.execute("edit.undo", &json!({})).unwrap();
+    let revision = s.revision;
+    save(&mut s, json!({"exposure_ev":2}));
+    assert_eq!(s.redo.len(), 1, "a no-op edit preserves redo");
+    assert_eq!(s.revision, revision);
+    s.execute("edit.redo", &json!({})).unwrap();
+    s.restore_checkpoint(checkpoint).unwrap();
+    assert_eq!(s.doc.render.setups["Studio"].width, 1024);
+    assert!(Arc::ptr_eq(&model, &s.model.state()));
+    assert!(Arc::ptr_eq(&mesh, &s.model.state().bodies[0].mesh()));
+    assert!(Arc::ptr_eq(&world, &s.world_state()));
+    assert_eq!(s.evaluations, 0);
+    // A geometry change and its history still require normal evaluation.
+    s.execute("solid.box", &json!({"length":2,"width":3,"height":4})).unwrap();
+    assert!(s.evaluations > 0);
+    s.evaluations = 0;
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert!(s.evaluations > 0);
+    s.evaluations = 0;
+    s.execute("edit.redo", &json!({})).unwrap();
+    assert!(s.evaluations > 0);
+    let checkpoint = s.checkpoint();
+    let expected = s.doc.clone();
+    s.execute("solid.box", &json!({"length":1,"width":1,"height":1})).unwrap();
+    s.evaluations = 0;
+    s.execute("edit.restore_checkpoint", &json!({"checkpoint":checkpoint})).unwrap();
+    assert_eq!(*s.doc, *expected);
+    assert!(s.evaluations > 0);
+}
+
+#[test]
+fn invalid_settings_and_limit_are_atomic() {
+    let mut s = Session::default();
+    let mut camera_with_typo = serde_json::to_value(solidcraft_render::Camera::default()).unwrap();
+    camera_with_typo["fov_degrees"] = json!(45);
+    for patch in [
+        json!({"width":0}),
+        json!({"width":4097}),
+        json!({"height":null}),
+        json!({"unknown":true}),
+        json!({"camera":{"distance":0}}),
+        json!({"camera":camera_with_typo}),
+        json!({"exposure_ev":33}),
+        json!({"environment_intensity":101}),
+    ] {
+        let doc = s.doc.clone();
+        let state = (s.revision, s.undo.len(), s.redo.len(), s.evaluations);
+        assert!(s.execute("render.settings.set", &json!({"name":"Studio","set":patch})).is_err());
+        assert!(Arc::ptr_eq(&doc, &s.doc));
+        assert_eq!(state, (s.revision, s.undo.len(), s.redo.len(), s.evaluations));
+    }
+    for i in 0..32 {
+        s.execute("render.settings.set", &json!({"name":i.to_string(),"set":{}})).unwrap();
+    }
+    let doc = s.doc.clone();
+    assert!(s.execute("render.settings.set", &json!({"name":"overflow","set":{}})).is_err());
+    assert!(Arc::ptr_eq(&doc, &s.doc));
+    assert!(s.execute("render.settings.get", &json!({"name":"missing"})).is_err());
+    assert_eq!(s.evaluations, 0);
+}
+
+#[test]
+fn settings_history_and_checkpoint_preserve_a_stale_live_drag() {
+    let mut s = Session::default();
+    for (id, p) in [
+        ("sketch.create", json!({"plane":"XY"})),
+        ("sketch.rectangle.two_point", json!({"p0":[5,5],"p1":[25,20]})),
+        ("sketch.dimension", json!({"entities":["l1"],"value":20})),
+        ("sketch.dimension", json!({"entities":["l2"],"value":15})),
+        ("sketch.finish", json!({})),
+        ("solid.extrude", json!({"distance":5})),
+        ("sketch.edit", json!({"sketch":"Sketch1"})),
+        ("sketch.drag", json!({"entity":"l1.start","from":[5,5],"to":[4,5],"live":true})),
+    ] {
+        s.execute(id, &p).unwrap();
+    }
+    assert!(s.model.is_stale());
+    let model = s.model.state();
+    s.evaluations = 0;
+    let checkpoint = s.execute("edit.checkpoint", &json!({})).unwrap()["checkpoint"].clone();
+    save(&mut s, json!({"exposure_ev":1}));
+    s.execute("render.settings.get", &json!({"name":"Studio"})).unwrap();
+    s.execute("edit.undo", &json!({})).unwrap();
+    s.execute("edit.redo", &json!({})).unwrap();
+    s.execute("edit.restore_checkpoint", &json!({"checkpoint":checkpoint})).unwrap();
+    assert!(s.doc.render.is_empty());
+    assert!(s.model.is_stale());
+    assert!(Arc::ptr_eq(&model, &s.model.state()));
+    assert_eq!(s.evaluations, 0);
+    s.execute("sketch.finish", &json!({})).unwrap();
+    assert!(!s.model.is_stale());
+    assert!(s.evaluations > 0);
+}