From fa5d3496ef0b408d2bc6c4c8850f8907a3828e01 Mon Sep 17 00:00:00 2001
From: wpumacay <wpumacay@gmail.com>
Date: Wed, 24 Sep 2025 21:05:14 -0700
Subject: [PATCH] Adds a fix for parsing gridlayout

- Resets the gridlayout string to zeros with memset to avoid taking the
  extra characters that are not copied when using memcpy with a shorter
  string
- Adds a test for this when using mjSpec
---
 src/xml/xml_native_reader.cc       |  1 +
 test/xml/xml_native_reader_test.cc | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/xml/xml_native_reader.cc b/src/xml/xml_native_reader.cc
index 4a6041733b..75093eeb73 100644
--- a/src/xml/xml_native_reader.cc
+++ b/src/xml/xml_native_reader.cc
@@ -3264,6 +3264,7 @@ void mjXReader::Asset(XMLElement* section, const mjVFS* vfs) {
           throw mjXError(elem, "gridlayout length must match gridsize");
         }
 
+        memset(texture->gridlayout, 0, sizeof(texture->gridlayout));
         memcpy(texture->gridlayout, text.data(), text.length());
       }
 
diff --git a/test/xml/xml_native_reader_test.cc b/test/xml/xml_native_reader_test.cc
index b6c0779ad7..fdfea80953 100644
--- a/test/xml/xml_native_reader_test.cc
+++ b/test/xml/xml_native_reader_test.cc
@@ -1967,6 +1967,26 @@ TEST_F(XMLReaderTest, ResizeKeyframeAfterParsing) {
   mj_deleteVFS(vfs.get());
 }
 
+TEST_F(XMLReaderTest, CheckTextureGridlayoutParsing) {
+  static constexpr char xml[] = R"(
+  <mujoco>
+    <asset>
+      <texture name="test_skybox" type="skybox" file="dummy_image.png" gridsize="2 4" gridlayout="LFRB.D.."/>
+    </asset>
+  </mujoco>
+  )";
+
+  std::array<char, 1024> error;
+  mjSpec* spec = mj_parseXMLString(xml, 0, error.data(), error.size());
+  EXPECT_THAT(spec, NotNull()) << error.data();
+  auto skybox_spec = mjs_asTexture(mjs_findElement(spec, mjOBJ_TEXTURE, "test_skybox"));
+  EXPECT_THAT(skybox_spec, NotNull()) << error.data();
+  EXPECT_EQ(std::strlen(skybox_spec->gridlayout), 8);
+  EXPECT_TRUE(std::strcmp(skybox_spec->gridlayout, "LFRB.D..") == 0);
+
+  mj_deleteSpec(spec);
+}
+
 // ----------------------- test camera parsing ---------------------------------
 
 TEST_F(XMLReaderTest, CameraInvalidFovyAndSensorsize) {