From f1bdf43e157c8d3b187c0fbe0a0d144d2dac5e4b Mon Sep 17 00:00:00 2001
From: Thomas Gamper <tgamper@ptc.com>
Date: Mon, 5 Feb 2024 16:50:46 +0100
Subject: [PATCH] tiny_gltf.h - add/remove MSFT_extension as required

---
 tiny_gltf.h | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 63 insertions(+), 3 deletions(-)

diff --git a/tiny_gltf.h b/tiny_gltf.h
index 6a04d6d..7ef28f4 100644
--- a/tiny_gltf.h
+++ b/tiny_gltf.h
@@ -7617,11 +7617,40 @@ static void SerializeGltfMaterial(const Material &material, detail::json &o) {
   }
 
   SerializeParameterMap(material.additionalValues, o);
-#else
-
 #endif
 
   SerializeExtrasAndExtensions(material, o);
+
+  // MSFT_lod
+  if (!material.lods.empty()) {
+    detail::json_iterator it;
+    if (!detail::FindMember(o, "extensions", it)) {
+      detail::json extensions;
+      detail::JsonSetObject(extensions);
+      detail::JsonAddMember(o, "extensions", std::move(extensions));
+      detail::FindMember(o, "extensions", it);
+    }
+    auto &extensions = detail::GetValue(it);
+    if (!detail::FindMember(extensions, "MSFT_lod", it)) {
+      detail::json lod;
+      detail::JsonSetObject(lod);
+      detail::JsonAddMember(extensions, "MSFT_lod", std::move(lod));
+      detail::FindMember(extensions, "MSFT_lod", it);
+    }
+    SerializeNumberArrayProperty<int>("ids", material.lods, detail::GetValue(it));
+  } else {
+    detail::json_iterator ext_it;
+    if (detail::FindMember(o, "extensions", ext_it)) {
+      auto &extensions = detail::GetValue(ext_it);
+      detail::json_iterator lp_it;
+      if (detail::FindMember(extensions, "MSFT_lod", lp_it)) {
+        detail::Erase(extensions, lp_it);
+      }
+      if (detail::IsEmpty(extensions)) {
+        detail::Erase(o, ext_it);
+      }
+    }
+  }
 }
 
 static void SerializeGltfMesh(const Mesh &mesh, detail::json &o) {
@@ -7844,7 +7873,7 @@ static void SerializeGltfNode(const Node &node, detail::json &o) {
       detail::json audio;
       detail::JsonSetObject(audio);
       detail::JsonAddMember(extensions, "KHR_audio", std::move(audio));
-      detail::FindMember(o, "KHR_audio", it);
+      detail::FindMember(extensions, "KHR_audio", it);
     }
     SerializeNumberProperty("emitter", node.emitter, detail::GetValue(it));
   } else {
@@ -7861,6 +7890,37 @@ static void SerializeGltfNode(const Node &node, detail::json &o) {
     }
   }
 
+  // MSFT_lod
+  if (!node.lods.empty()) {
+    detail::json_iterator it;
+    if (!detail::FindMember(o, "extensions", it)) {
+      detail::json extensions;
+      detail::JsonSetObject(extensions);
+      detail::JsonAddMember(o, "extensions", std::move(extensions));
+      detail::FindMember(o, "extensions", it);
+    }
+    auto &extensions = detail::GetValue(it);
+    if (!detail::FindMember(extensions, "MSFT_lod", it)) {
+      detail::json lod;
+      detail::JsonSetObject(lod);
+      detail::JsonAddMember(extensions, "MSFT_lod", std::move(lod));
+      detail::FindMember(extensions, "MSFT_lod", it);
+    }
+    SerializeNumberArrayProperty<int>("ids", node.lods, detail::GetValue(it));
+  } else {
+    detail::json_iterator ext_it;
+    if (detail::FindMember(o, "extensions", ext_it)) {
+      auto &extensions = detail::GetValue(ext_it);
+      detail::json_iterator lp_it;
+      if (detail::FindMember(extensions, "MSFT_lod", lp_it)) {
+        detail::Erase(extensions, lp_it);
+      }
+      if (detail::IsEmpty(extensions)) {
+        detail::Erase(o, ext_it);
+      }
+    }
+  }
+
   if (!node.name.empty()) SerializeStringProperty("name", node.name, o);
   SerializeNumberArrayProperty<int>("children", node.children, o);
 }