fix(ugc): transparent bricks drawn see-through in mixed models; dUgcServer in folders by role

- The client puts a shape in its sorted, blended pass only when its
  NiMaterialProperty alpha is under 0.99999 (ShaderCommon::GetAlphaFlags
  0x0109f5a0; the NiAlphaProperty blend flag isn't read); at 1.0 it's drawn
  solid with blending off. Transparent (and transparent glitter) shapes now
  get a material with alpha 0.9999, as the S01_Alpha shapes of the game's own
  brick models (res/BrickModels/ndmade) do; opaque shapes keep 1.0. Models
  with a transparent brick change; the others are byte for byte the same.
- dUgcServer's files move into Bricks/, Model/, Render/, Formats/ and
  Processing/ (the CMakeLists says what each holds); includes are unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dUgcServer/CMakeLists.txt

@@ -1,25 +1,34 @@
+# The UGC server (docs/UgcServer.md), in folders by role:
+#   Bricks/      the client's brick data: primitives, Materials.xml, LU Toolbox's palette, the CDClient's module data
+#   Model/       player models built from LXFML, car and rocket module combinations, glitter
+#   Render/      the software rasterizer, ambient occlusion, hidden-face removal, icon parameters and pose
+#   Formats/     the files written for the client and the dashboard (NIF, DDS, PNG, sd0)
+#   Processing/  the job queue and workers, the CPU budget, stored files
+#   UgcServer.cpp  the server: settings, the master link, HTTP routes
+
 # The pure part of the UGC server (brick data, meshes, rendering, file formats, storage), shared with the tests
 set(DUGC_SOURCES
-	"UgcBricks.cpp"
-	"UgcFormats.cpp"
-	"UgcGlitter.cpp"
-	"UgcHsr.cpp"
-	"UgcIconParams.cpp"
-	"UgcIconPose.cpp"
-	"UgcJobs.cpp"
-	"UgcModel.cpp"
-	"UgcModular.cpp"
-	"UgcPalette.cpp"
-	"UgcRender.cpp"
-	"UgcStorage.cpp"
-	"UgcThrottle.cpp"
+	"Bricks/UgcBricks.cpp"
+	"Bricks/UgcPalette.cpp"
+	"Formats/UgcFormats.cpp"
+	"Model/UgcGlitter.cpp"
+	"Model/UgcModel.cpp"
+	"Model/UgcModular.cpp"
+	"Processing/UgcJobs.cpp"
+	"Processing/UgcStorage.cpp"
+	"Processing/UgcThrottle.cpp"
+	"Render/UgcHsr.cpp"
+	"Render/UgcIconParams.cpp"
+	"Render/UgcIconPose.cpp"
+	"Render/UgcRender.cpp"
 )
 
 add_library(dUgc STATIC ${DUGC_SOURCES})
-target_include_directories(dUgc PUBLIC "." "${PROJECT_SOURCE_DIR}/thirdparty/MD5" "${PROJECT_SOURCE_DIR}/thirdparty/nlohmann")
+target_include_directories(dUgc PUBLIC "." "Bricks" "Formats" "Model" "Processing" "Render"
+	"${PROJECT_SOURCE_DIR}/thirdparty/MD5" "${PROJECT_SOURCE_DIR}/thirdparty/nlohmann")
 target_link_libraries(dUgc PUBLIC dCommon glm::glm tinyxml2 MD5)
 
-add_executable(UgcServer "UgcServer.cpp" "UgcProcessor.cpp" "UgcCdClient.cpp")
+add_executable(UgcServer "UgcServer.cpp" "Processing/UgcProcessor.cpp" "Bricks/UgcCdClient.cpp")
 
 target_include_directories(UgcServer PRIVATE
 	"${PROJECT_SOURCE_DIR}/dCommon"
@@ -42,5 +51,5 @@ target_link_libraries(UgcServer ${COMMON_LIBRARIES} dWeb dServer dUgc)
 
 # Rendering is far too slow unoptimized (minutes a model instead of seconds), so it is optimized in every build type
 if(NOT MSVC)
-	set_source_files_properties("UgcRender.cpp" "UgcHsr.cpp" "UgcModel.cpp" "UgcPalette.cpp" "UgcGlitter.cpp" PROPERTIES COMPILE_OPTIONS "-O2")
+	set_source_files_properties("Render/UgcRender.cpp" "Render/UgcHsr.cpp" "Model/UgcModel.cpp" "Bricks/UgcPalette.cpp" "Model/UgcGlitter.cpp" PROPERTIES COMPILE_OPTIONS "-O2")
 endif()

dUgcServer/Formats/UgcFormats.cpp

@@ -228,8 +228,8 @@ namespace {
 			m_VertexColor = nif.Add("NiVertexColorProperty", std::move(vertexColor.Data()));
 		}
 
-		// A white NiMaterialProperty with this emissive color (grey)
-		static std::string Material(float emissive) {
+		// A white NiMaterialProperty with this emissive color (grey) and alpha
+		static std::string Material(float emissive, float alpha = 1.0f) {
 			Writer material;
 			WriteNet(material, -1);
 			for (int i = 0; i < 3; i++) material.Float(1.0f); // ambient
@@ -237,7 +237,7 @@ namespace {
 			for (int i = 0; i < 3; i++) material.Float(0.0f); // specular
 			for (int i = 0; i < 3; i++) material.Float(emissive);
 			material.Float(4.0f);  // glossiness, as the game's brick models
-			material.Float(1.0f);  // alpha
+			material.Float(alpha);
 			return std::move(material.Data());
 		}
 
@@ -383,8 +383,15 @@ namespace {
 				specular.U16(0); // off
 				m_Specular = m_Nif.Add("NiSpecularProperty", std::move(specular.Data()));
 			}
-			(void)transparent;
+			// The client draws a shape in its sorted, blended pass only when the material's alpha is under 0.99999
+			// (ShaderCommon::GetAlphaFlags 0x0109f5a0; the NiAlphaProperty's blend flag isn't read): at 1.0 a
+			// transparent brick is drawn solid, with blending off. The game's own brick models give their S01_Alpha
+			// shapes 0.9999, and so do we (made once a file, only when there is a transparent shape).
 			int32_t material = m_Material;
+			if (transparent) {
+				if (m_MaterialAlpha < 0) m_MaterialAlpha = m_Nif.Add("NiMaterialProperty", Material(0.0f, 0.9999f));
+				material = m_MaterialAlpha;
+			}
 			if (emissive > 0.0f) {
 				auto [it, added] = m_Emissive.try_emplace(emissive, -1);
 				if (added) it->second = m_Nif.Add("NiMaterialProperty", Material(emissive));
@@ -409,6 +416,7 @@ namespace {
 	private:
 		NifBuilder& m_Nif;
 		int32_t m_Material{ -1 };
+		int32_t m_MaterialAlpha{ -1 }; // transparent shapes' (alpha 0.9999)
 		int32_t m_VertexColor{ -1 };
 		int32_t m_Alpha{ -1 };
 		int32_t m_Specular{ -1 };