animation: six character-motion panel transitions, composed in the core so backends agree

1 files changed, 9 insertions, 2 deletions

diff --git a/shaders/crt.ci.metal b/shaders/crt.ci.metal
index e1db5770..414e9cdc 100644
--- a/shaders/crt.ci.metal
+++ b/shaders/crt.ci.metal
@@ -102,6 +102,13 @@ bool pardesInside(float2 p, float4 box) {
         p.x < box.x + box.z && p.y < box.y + box.w;
 }
 
+// Character effects (ASCII byte walks, glyph motion, per-cell locks) are
+// composed in Pardes core, so this kernel never eases them: it clips their
+// panel batch and draws the finished glyphs.
+bool pardesComposedInCore(float effect) {
+    return effect == 4.0 || effect >= 6.0;
+}
+
 float pardesPanelProgress(float effect, float frame) {
     float frames = effect == 1.0 ? 12.0 :
         effect == 2.0 ? 14.0 :
@@ -120,7 +127,7 @@ float pardesPanelProgress(float effect, float frame) {
         return 1.0 + c3 * u * u * u + c1 * u * u;
     }
     if (effect == 3.0) return t * t * (3.0 - 2.0 * t); // dissolve
-    return t; // ASCII cells are already composed; retained for ABI completeness
+    return t; // core-composed cells need no progress; retained for ABI completeness
 }
 
 // Prepare every geometric target before any translated panel is drawn. A
@@ -171,7 +178,7 @@ extern "C" float4 pardesPanel(
     // ASCII bytes were already composed in Pardes core before CoreText built
     // `current`. Pixel attachments have no character value and intentionally
     // pass through unchanged, so this kernel only clips the pane batch.
-    if (effect == 4.0) {
+    if (pardesComposedInCore(effect)) {
         if (!pardesInside(coord, target)) return underneath;
         return current.sample(current.transform(coord));
     }