Merge branch 'worktree-agent-afea1146abae6192c'

# Conflicts:
#	apps/effectcraft-cli/Cargo.toml
#	apps/effectcraft-cli/src/main.rs
#	crates/render/src/lib.rs

crates/engine/src/lib.rs

@@ -17,7 +17,7 @@ use std::sync::Arc;
 
 use effectcraft_project::{Comp, ItemId, Layer, LayerId, Project, Uid};
 use effectcraft_raster::Image;
-use effectcraft_render::{ExprHost, FootageSource, NoFootage, RenderOpts, Renderer};
+use effectcraft_render::{ExprHost, FootageSource, LayerCache, NoFootage, RenderOpts, Renderer};
 use effectcraft_time::Tick;
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
@@ -141,6 +141,8 @@ pub struct Session {
     pub events: Vec<Event>,
     /// Commands executed: (id, params).
     pub journal: Vec<(String, Value)>,
+    /// Processed-layer pixels reused across frames and edits (content-keyed, never stale).
+    pub layer_cache: Arc<LayerCache>,
 }
 
 impl Default for Session {
@@ -160,6 +162,7 @@ impl Default for Session {
             render_job: None,
             events: vec![],
             journal: vec![],
+            layer_cache: Arc::new(LayerCache::default()),
         }
     }
 }
@@ -319,6 +322,7 @@ impl Session {
     pub fn render(&self, comp: ItemId, t: Tick, opts: RenderOpts) -> Image {
         let mut r = Renderer::new(&self.project, self.footage.as_ref(), opts);
         r.expr = self.expr.as_deref();
+        r.cache = Some(&self.layer_cache);
         r.comp_frame(comp, t)
     }
 

crates/engine/src/tests.rs

@@ -18,6 +18,35 @@ fn demo_opens_and_renders() {
     assert!(lit > 100_000, "{lit}");
 }
 
+/// The session's layer cache never changes pixels: scrubbing the demo (including back and
+/// forth, and across an edit made through a command) matches cache-less renders exactly.
+#[test]
+fn demo_layer_cache_is_transparent() {
+    let mut s = demo();
+    let cid = s.active_comp_id().unwrap();
+    let opts = effectcraft_render::RenderOpts { scale: 0.25, ..Default::default() };
+    let uncached = |s: &Session, t: f64| {
+        let mut r = effectcraft_render::Renderer::new(&s.project, s.footage.as_ref(), opts);
+        r.expr = s.expr.as_deref();
+        r.comp_frame(cid, effectcraft_time::Tick::from_seconds_f64(t))
+    };
+    let check = |s: &Session, t: f64| {
+        let a = s.render(cid, effectcraft_time::Tick::from_seconds_f64(t), opts);
+        let b = uncached(s, t);
+        assert!(a.data.iter().zip(&b.data).all(|(p, q)| (0..4).all(|c| (p[c] - q[c]).abs() < 1e-6)), "t={t}");
+    };
+    for t in [0.5, 1.0, 3.0, 3.0334, 6.0, 3.0, 0.5] {
+        check(&s, t);
+    }
+    assert!(s.layer_cache.stats().hits > 0);
+    // Edit the title's glow through the command layer, then scrub again.
+    let title = s.project.comp(cid).unwrap().layers.iter().find(|l| l.name == "EFFECTCRAFT").map(|l| l.id.0).unwrap();
+    s.execute("prop.set", json!({"layer": title, "path": "effects/#1/radius", "value": 5.0})).unwrap();
+    for t in [3.0, 0.5] {
+        check(&s, t);
+    }
+}
+
 #[test]
 fn every_command_has_unique_id_and_runs_or_reports() {
     let mut ids = std::collections::HashSet::new();