From 97f3bf2c2070dfba4176c69384f936dd53a9b33f Mon Sep 17 00:00:00 2001
From: Your Name <your.email@example.com>
Date: Mon, 6 Apr 2026 01:44:36 +0800
Subject: [PATCH] fix: tune granular splat reveal timing

---
 components/canvas/world3d/World3DViewer.tsx | 51 ++++++++++++++-------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/components/canvas/world3d/World3DViewer.tsx b/components/canvas/world3d/World3DViewer.tsx
index d158a8840..33e0e90ec 100644
--- a/components/canvas/world3d/World3DViewer.tsx
+++ b/components/canvas/world3d/World3DViewer.tsx
@@ -104,10 +104,10 @@ const SPLAT_LOADING_PROFILE: SparkRevealProfile = {
 const SPLAT_PARTICLE_PROFILE: SparkRevealProfile = {
   blurAmount: 0.01,
   preBlurAmount: 0,
-  minAlpha: 0.19,
-  maxStdDev: Math.sqrt(2.2),
-  focalAdjustment: 2.35,
-  falloff: 0.2,
+  minAlpha: 0.28,
+  maxStdDev: Math.sqrt(1.45),
+  focalAdjustment: 3.05,
+  falloff: 0.08,
   opacity: 1,
 };
 
@@ -155,6 +155,8 @@ function lerpSparkRevealProfile(
   };
 }
 
+const SPLAT_REVEAL_DURATION_MS = 2600;
+
 const KEY_TO_MOVEMENT: Partial<Record<string, MovementCommand>> = {
   KeyW: "forward",
   ArrowUp: "forward",
@@ -582,23 +584,38 @@ function WorldSplatScene({
     const phase = revealPhaseRef.current;
     const revealElapsed =
       phase === "revealing"
-        ? Math.min((performance.now() - revealStartedAtRef.current) / 1650, 1)
+        ? Math.min((performance.now() - revealStartedAtRef.current) / SPLAT_REVEAL_DURATION_MS, 1)
         : 0;
-    const easedReveal = 1 - Math.pow(1 - revealElapsed, 3);
+    const easedReveal = THREE.MathUtils.smoothstep(revealElapsed, 0, 1);
 
     if (phase === "loading") {
       applySparkRevealProfile(sparkRenderer, splatMesh, SPLAT_LOADING_PROFILE);
     } else if (phase === "revealing") {
-      const particleHold = 0.32;
-      const granularProgress =
-        easedReveal <= particleHold
-          ? 0
-          : (easedReveal - particleHold) / (1 - particleHold);
-      const profile = lerpSparkRevealProfile(
-        SPLAT_PARTICLE_PROFILE,
-        SPLAT_NORMAL_PROFILE,
-        THREE.MathUtils.smoothstep(granularProgress, 0, 1)
-      );
+      const particleIntroEnd = 0.2;
+      const particleHoldEnd = 0.6;
+      let profile = SPLAT_PARTICLE_PROFILE;
+
+      if (easedReveal < particleIntroEnd) {
+        profile = lerpSparkRevealProfile(
+          SPLAT_LOADING_PROFILE,
+          SPLAT_PARTICLE_PROFILE,
+          THREE.MathUtils.smoothstep(easedReveal / particleIntroEnd, 0, 1)
+        );
+      } else if (easedReveal < particleHoldEnd) {
+        const pulse = Math.sin((performance.now() - revealStartedAtRef.current) * 0.008) * 0.02;
+        profile = {
+          ...SPLAT_PARTICLE_PROFILE,
+          minAlpha: SPLAT_PARTICLE_PROFILE.minAlpha + pulse,
+          focalAdjustment: SPLAT_PARTICLE_PROFILE.focalAdjustment + pulse * 2.4,
+        };
+      } else {
+        const granularProgress = (easedReveal - particleHoldEnd) / (1 - particleHoldEnd);
+        profile = lerpSparkRevealProfile(
+          SPLAT_PARTICLE_PROFILE,
+          SPLAT_NORMAL_PROFILE,
+          THREE.MathUtils.smoothstep(granularProgress, 0, 1)
+        );
+      }
       applySparkRevealProfile(sparkRenderer, splatMesh, profile);
     } else {
       applySparkRevealProfile(sparkRenderer, splatMesh, SPLAT_NORMAL_PROFILE);
@@ -757,7 +774,7 @@ function WorldSplatViewer({
       setOverlayPhase("revealing");
       const timer = window.setTimeout(() => {
         setOverlayPhase("hidden");
-      }, 1650);
+      }, SPLAT_REVEAL_DURATION_MS);
       return () => window.clearTimeout(timer);
     }