Track matte on an adjustment layer limits where its effects show (fixes #1201)

crates/gpu/src/tests_adjust.rs

@@ -3,7 +3,7 @@
 
 use effectcraft_keyframe::{ShapePath, Value};
 use effectcraft_project::build::{self, Ids};
-use effectcraft_project::{BitDepth, ColorSpace, MaskMode};
+use effectcraft_project::{BitDepth, ColorSpace, MaskMode, MatteKind, TrackMatte};
 use effectcraft_render::{Backend, FxStep, FxTarget, RenderOpts, Renderer};
 use effectcraft_time::Tick;
 
@@ -72,6 +72,24 @@ fn mixed_adjustment_chains_fall_back_per_effect() {
     }
 }
 
+/// A track matte limits where the adjustment shows, as on the CPU (#1201).
+#[test]
+fn track_mattes_limit_gpu_adjustments_like_the_cpu() {
+    for depth in [BitDepth::Bpc8, BitDepth::Bpc32] {
+        for kind in [MatteKind::Alpha, MatteKind::AlphaInverted, MatteKind::Luma, MatteKind::LumaInverted] {
+            let mut s = adjustment_scene(depth, &gpu_stack(), false);
+            let mut matte = s.footage(50, 30);
+            matte.switches.video = false;
+            set(&mut matte, "transform/rotation", Value::Scalar(10.0));
+            let mid = s.push(matte);
+            let c = s.p.comp_mut(s.cid).unwrap();
+            let adj = c.layers.iter_mut().find(|l| l.switches.adjustment).unwrap();
+            adj.track_matte = Some(TrackMatte { layer: mid, kind });
+            check(&format!("matted adjustment {kind:?} {depth:?}"), compare_at(&s, opts(), Tick::ZERO), 0.0);
+        }
+    }
+}
+
 /// Counts where each run of the stack goes.
 #[derive(Default)]
 struct Probe {

crates/gpu/src/walk.rs

@@ -297,12 +297,14 @@ fn draw_precomp(e: &mut Enc, r: &Renderer, ctx: &EvalCtx, layer: &Layer, canvas:
 
 /// Adjustment layer (`Renderer::draw_adjustment`): the effect stack runs on the comp below,
 /// resident on the GPU (non-GPU effects read back, run on the CPU and upload), and the result
-/// replaces the canvas inside the layer's footprint × opacity. `None` = draw it on the CPU.
+/// replaces the canvas inside the layer's footprint × track matte × opacity. `None` = draw it
+/// on the CPU.
 fn draw_adjustment(e: &mut Enc, r: &Renderer, ctx: &EvalCtx, layer: &Layer, canvas: &mut GpuImage) -> Option<()> {
     let opacity = r.layer_opacity(ctx, layer);
     let Some(foot) = r.adjustment_footprint(ctx, layer) else { return Some(()) };
     let (w, h) = (canvas.width, canvas.height);
     let matte = place(e, r, ctx, layer, &foot, &e.zeros(w, h), BlendMode::Normal, 1.0, None)?;
+    let matte = track_matte(e, r, ctx, layer, matte, None)?;
     let pipe = r.pipe();
     // Effects run in the working space, not the linear blending space.
     let below = match pipe.from_blend() {
@@ -353,22 +355,7 @@ fn composite_iso_with(
     matte_img: Option<GpuImage>,
     levels: Option<f32>,
 ) -> Option<()> {
-    if let Some((m, kind)) = r.track_matte(ctx, layer) {
-        let mimg = match matte_img.filter(|i| (i.width, i.height) == (canvas.width, canvas.height)) {
-            Some(i) => i,
-            None => {
-                let mut mimg = e.zeros(canvas.width, canvas.height);
-                if m.is_active_at(ctx.time)
-                    && let Some(mb) = r.layer_buf(ctx, m)
-                {
-                    let mo = ctx.opacity(m) as f32;
-                    mimg = place(e, r, ctx, m, &mb, &mimg, BlendMode::Normal, mo, None)?;
-                }
-                mimg
-            }
-        };
-        iso = ops::matte(e, &iso, &mimg, kind);
-    }
+    iso = track_matte(e, r, ctx, layer, iso, matte_img)?;
     if layer.preserve_transparency {
         iso = ops::preserve(e, &iso, canvas);
     }
@@ -376,6 +363,26 @@ fn composite_iso_with(
     Some(())
 }
 
+/// `Renderer::apply_track_matte`: `img` (comp-sized) times the layer's track matte, if it has
+/// one; `matte_img` as in [`composite_iso_with`].
+fn track_matte(e: &mut Enc, r: &Renderer, ctx: &EvalCtx, layer: &Layer, img: GpuImage, matte_img: Option<GpuImage>) -> Option<GpuImage> {
+    let Some((m, kind)) = r.track_matte(ctx, layer) else { return Some(img) };
+    let mimg = match matte_img.filter(|i| (i.width, i.height) == (img.width, img.height)) {
+        Some(i) => i,
+        None => {
+            let mut mimg = e.zeros(img.width, img.height);
+            if m.is_active_at(ctx.time)
+                && let Some(mb) = r.layer_buf(ctx, m)
+            {
+                let mo = ctx.opacity(m) as f32;
+                mimg = place(e, r, ctx, m, &mb, &mimg, BlendMode::Normal, mo, None)?;
+            }
+            mimg
+        }
+    };
+    Some(ops::matte(e, &img, &mimg, kind))
+}
+
 /// Draw a processed layer buffer onto `target` (transform, motion blur sub-samples), quantising
 /// the result to `levels` when set.
 #[allow(clippy::too_many_arguments)]

crates/render/src/lib.rs

@@ -1945,13 +1945,26 @@ impl<'a> Renderer<'a> {
     /// [`Self::composite_iso`] with the track matte's pixels already drawn (`matte`, e.g. a 3D
     /// matte seen through the camera); otherwise the matte layer is placed in 2D.
     pub(crate) fn composite_iso_with(&self, ctx: &EvalCtx, layer: &Layer, mut iso: Image, canvas: &mut Image, opacity: f32, matte_img: Option<Image>) {
+        self.apply_track_matte(ctx, layer, &mut iso, matte_img);
+        if layer.preserve_transparency {
+            iso.data.par_iter_mut().zip(canvas.data.par_iter()).for_each(|(p, q)| {
+                for c in p.iter_mut() {
+                    *c *= q[3];
+                }
+            });
+        }
+        canvas.blend_from(&iso, layer.blend_mode, opacity, layer.id.0 as u32);
+    }
+
+    /// Multiply `img` (comp-sized) by the layer's track matte, if it has one; `matte_img` as in
+    /// [`Self::composite_iso_with`].
+    fn apply_track_matte(&self, ctx: &EvalCtx, layer: &Layer, img: &mut Image, matte_img: Option<Image>) {
         let matte = layer.track_matte.and_then(|tm| ctx.comp.layer(tm.layer).filter(|m| m.id != layer.id).map(|m| (m, tm.kind)));
-        let preserve = layer.preserve_transparency;
         if let Some((m, kind)) = matte {
             let mimg = match matte_img {
-                Some(i) if i.width == canvas.width && i.height == canvas.height => i,
+                Some(i) if i.width == img.width && i.height == img.height => i,
                 _ => {
-                    let mut mimg = Image::new(canvas.width, canvas.height);
+                    let mut mimg = Image::new(img.width, img.height);
                     if m.is_active_at(ctx.time)
                         && let Some(mb) = self.layer_buf(ctx, m)
                     {
@@ -1961,7 +1974,7 @@ impl<'a> Renderer<'a> {
                     mimg
                 }
             };
-            iso.data.par_iter_mut().zip(mimg.data.par_iter()).for_each(|(p, q)| {
+            img.data.par_iter_mut().zip(mimg.data.par_iter()).for_each(|(p, q)| {
                 let k = match kind {
                     MatteKind::Alpha => q[3],
                     MatteKind::AlphaInverted => 1.0 - q[3],
@@ -1974,22 +1987,16 @@ impl<'a> Renderer<'a> {
                 }
             });
         }
-        if preserve {
-            iso.data.par_iter_mut().zip(canvas.data.par_iter()).for_each(|(p, q)| {
-                for c in p.iter_mut() {
-                    *c *= q[3];
-                }
-            });
-        }
-        canvas.blend_from(&iso, layer.blend_mode, opacity, layer.id.0 as u32);
     }
 
-    /// Adjustment layer: effects applied to the comp below, limited to the layer's footprint.
+    /// Adjustment layer: effects applied to the comp below, limited to the layer's footprint
+    /// and its track matte.
     fn draw_adjustment(&self, ctx: &EvalCtx, layer: &Layer, canvas: &mut Image, opacity: f32) {
         let Some(mut foot) = self.source(ctx, layer) else { return };
         let _ = masks::apply(ctx, layer, &mut foot, self.mask_blur(ctx, layer));
         let mut matte = Image::new(canvas.width, canvas.height);
         self.place(ctx, layer, &foot, &mut matte, BlendMode::Normal, 1.0);
+        self.apply_track_matte(ctx, layer, &mut matte, None);
         let o = self.roi_offset().map(|(x, y, _, _)| [-x, -y]).unwrap_or([0.0; 2]);
         let mut below = Buf { img: canvas.clone(), offset: o, scale: self.opts.scale };
         // Effects run in the working space, not the linear blending space.

crates/render/src/tests.rs

@@ -161,6 +161,32 @@ fn track_matte_kinds_keep_and_invert() {
     }
 }
 
+/// An adjustment layer with a track matte applies its effects only where the matte allows: an
+/// Invert over a 0.25 grey with an opaque white 50×50 matte at the left of the comp (#1201).
+#[test]
+fn track_matte_limits_an_adjustment_layer() {
+    for (kind, inside) in [(MatteKind::Alpha, true), (MatteKind::AlphaInverted, false), (MatteKind::Luma, true), (MatteKind::LumaInverted, false)] {
+        let (mut p, cid, comp) = setup();
+        let mut matte = solid(&mut p, &comp, [1.0, 1.0, 1.0], 50, 50);
+        matte.props.prop_mut("transform/position").unwrap().value = Value::Vec3([50.0, 50.0, 0.0]);
+        matte.switches.video = false;
+        let mut adj = solid(&mut p, &comp, [1.0, 1.0, 1.0], 200, 100);
+        adj.switches.adjustment = true;
+        add_effect_200(&mut p, &mut adj, "ec.channel.invert", &[]);
+        adj.track_matte = Some(TrackMatte { layer: matte.id, kind });
+        let bg = solid(&mut p, &comp, [0.25, 0.25, 0.25], 200, 100);
+        let c = p.comp_mut(cid).unwrap();
+        c.layers.push(matte);
+        c.layers.push(adj);
+        c.layers.push(bg);
+        let img = render_frame(&p, cid, Tick::ZERO, 1.0);
+        let (g_in, g_out) = (img.get(50, 50)[0], img.get(150, 50)[0]);
+        let (want_in, want_out) = if inside { (0.75, 0.25) } else { (0.25, 0.75) };
+        assert!((g_in - want_in).abs() < 1e-4 && (g_out - want_out).abs() < 1e-4, "{kind:?}: {g_in} inside, {g_out} outside");
+        assert_eq!(img.get(150, 50)[3], 1.0, "{kind:?} keeps the comp opaque");
+    }
+}
+
 #[test]
 fn shape_layer_draws_fill_and_stroke() {
     let (mut p, cid, comp) = setup();