From 70c9cb90a98cfdbcba4e6cee920b9d42c557dc52 Mon Sep 17 00:00:00 2001
From: Andreas Sundquist <asundqui@worldlabs.ai>
Date: Mon, 23 Jun 2025 14:43:30 -0700
Subject: [PATCH] Fix incorrect SH2 coefficient signs (#64)

---
 src/SplatMesh.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/SplatMesh.ts b/src/SplatMesh.ts
index b3def3a..e34579f 100644
--- a/src/SplatMesh.ts
+++ b/src/SplatMesh.ts
@@ -717,9 +717,9 @@ const defineEvaluateSH2 = unindent(`
     )) / 127.0;
 
     return sh2_0 * (1.0925484 * viewDir.x * viewDir.y)
-      + sh2_1 * (1.0925484 * viewDir.y * viewDir.z)
+      + sh2_1 * (-1.0925484 * viewDir.y * viewDir.z)
       + sh2_2 * (0.3153915 * (2.0 * viewDir.z * viewDir.z - viewDir.x * viewDir.x - viewDir.y * viewDir.y))
-      + sh2_3 * (1.0925484 * viewDir.x * viewDir.z)
+      + sh2_3 * (-1.0925484 * viewDir.x * viewDir.z)
       + sh2_4 * (0.5462742 * (viewDir.x * viewDir.x - viewDir.y * viewDir.y));
   }
 `);