1 files changed, 20 insertions, 36 deletions
diff --git a/tools/mq_editor/mq_extract.js b/tools/mq_editor/mq_extract.js
index 237f1ab..878b2bc 100644
--- a/tools/mq_editor/mq_extract.js
+++ b/tools/mq_editor/mq_extract.js
@@ -182,46 +182,30 @@ function trackPartials(frames, sampleRate) {
   return partials;
 }
 
-// Fit cubic bezier curve to trajectory
+// Fit cubic bezier curve to trajectory using Catmull-Rom tangents.
+// Estimates end tangents via forward/backward differences, then converts
+// Hermite form to Bezier: B1 = P0 + m0*dt/3, B2 = P3 - m3*dt/3.
+// This guarantees the curve passes through both endpoints.
 function fitBezier(times, values) {
-  if (times.length < 4) {
-    // Not enough points, just use linear segments
-    return {
-      t0: times[0], v0: values[0],
-      t1: times[0], v1: values[0],
-      t2: times[times.length-1], v2: values[values.length-1],
-      t3: times[times.length-1], v3: values[values.length-1]
-    };
-  }
-
-  // Fix endpoints
-  const t0 = times[0];
-  const t3 = times[times.length - 1];
-  const v0 = values[0];
-  const v3 = values[values.length - 1];
+  const n = times.length - 1;
+  const t0 = times[0],  v0 = values[0];
+  const t3 = times[n],  v3 = values[n];
+  const dt = t3 - t0;
 
-  // Solve for interior control points via least squares
-  // Simplification: place at 1/3 and 2/3 positions
-  const t1 = t0 + (t3 - t0) / 3;
-  const t2 = t0 + 2 * (t3 - t0) / 3;
+  if (dt <= 0 || n === 0) {
+    return {t0, v0, t1: t0, v1: v0, t2: t3, v2: v3, t3, v3};
+  }
 
-  // Find v1, v2 by evaluating at nearest data points
-  let v1 = v0, v2 = v3;
-  let minDist1 = Infinity, minDist2 = Infinity;
+  // Catmull-Rom endpoint tangents (forward diff at start, backward at end)
+  const dt0 = times[1] - times[0];
+  const m0  = dt0 > 0 ? (values[1] - values[0]) / dt0 : 0;
 
-  for (let i = 0; i < times.length; ++i) {
-    const dist1 = Math.abs(times[i] - t1);
-    const dist2 = Math.abs(times[i] - t2);
+  const dtn = times[n] - times[n - 1];
+  const m3  = dtn > 0 ? (values[n] - values[n - 1]) / dtn : 0;
 
-    if (dist1 < minDist1) {
-      minDist1 = dist1;
-      v1 = values[i];
-    }
-    if (dist2 < minDist2) {
-      minDist2 = dist2;
-      v2 = values[i];
-    }
-  }
+  // Hermite -> Bezier control points
+  const v1 = v0 + m0 * dt / 3;
+  const v2 = v3 - m3 * dt / 3;
 
-  return {t0, v0, t1, v1, t2, v2, t3, v3};
+  return {t0, v0, t1: t0 + dt / 3, v1, t2: t0 + 2 * dt / 3, v2, t3, v3};
 }