From ea8f6a3c92ee807be7cd9a13d2c0c4c43024af2f Mon Sep 17 00:00:00 2001
From: Doris Wu <doriswu@google.com>
Date: Fri, 23 Jan 2026 06:49:54 +0800
Subject: [PATCH] return empty string  for es2 (#9623)

---
 filament/backend/src/opengl/ShaderCompilerService.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/filament/backend/src/opengl/ShaderCompilerService.cpp b/filament/backend/src/opengl/ShaderCompilerService.cpp
index 6bcb782138..55c931c056 100644
--- a/filament/backend/src/opengl/ShaderCompilerService.cpp
+++ b/filament/backend/src/opengl/ShaderCompilerService.cpp
@@ -1089,9 +1089,16 @@ UTILS_NOINLINE
 
 /* static */ std::string_view process_countBits(OpenGLContext& context) noexcept {
     using namespace std::literals;
+    // bitCount is available in GL 4.0 and GLES 3.1.
     if (context.isAtLeastGL<4, 0>() || context.isAtLeastGLES<3, 1>()) {
         return ""sv;
     }
+
+    // GLES 2.0 does not support bitwise operations or unsigned integers.
+    if (context.isES2()) {
+        return ""sv;
+    }
+
     return R"(
 // https://graphics.stanford.edu/%7Eseander/bithacks.html
 int bitCount(highp uint value) {