Adding back resources

tests/SharpGLTF.Ext.3DTiles.Tests/GenericTests.cs

@@ -43,11 +43,7 @@ namespace SharpGLTF
         [TestCase("ValidFeatureIdTextureAndPropertyTable.gltf", null)]
         public void ReadGenericFiles(string file, Type exception = null)
         {
-            var fileName = ResourceInfo.From(file);
-
-            var exists = fileName.File.Exists;
-            var text = fileName.ReadAllText();
-            TestContext.WriteLine($"{exists} {text.Length}");
+            var fileName = ResourceInfo.From(file);            
 
             if (exception != null)
             {

tests/SharpGLTF.Ext.3DTiles.Tests/Properties/AssemblyInfo.cs

@@ -6,5 +6,5 @@ using System.Threading.Tasks;
 
 using NUnit.Framework;
 
-[assembly: ResourcePathFormat("*/TestFixtures")]
+[assembly: ResourcePathFormat("{ProjectDirectory}/TestFixtures")]
 [assembly: AttachmentPathFormat("*/TestResults/?", true)]

tests/SharpGLTF.Ext.3DTiles.Tests/SharpGLTF.Ext.3DTiles.Tests.csproj

@@ -10,11 +10,7 @@
   <ItemGroup>
     <ProjectReference Include="..\..\src\SharpGLTF.Ext.3DTiles\SharpGLTF.Ext.3DTiles.csproj" />
     <ProjectReference Include="..\SharpGLTF.NUnit\SharpGLTF.NUnit.csproj" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Content Include="TestFixtures\**\*" CopyToOutputDirectory="PreserveNewest" />
-  </ItemGroup>
+  </ItemGroup>  
 
   <ItemGroup>
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0">

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/FeatureIdAttributeAndPropertyTableFeatureIdNotInRange.gltf

@@ -0,0 +1,141 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "FeatureIdAttributeAndPropertyTableSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class",
+            "properties" : {
+              "example_VEC3_FLOAT32" : {
+                "name" : "Example VEC3 FLOAT32 property",
+                "description" : "An example property, with type VEC3, with component type FLOAT32",
+                "type" : "VEC3",
+                "componentType" : "FLOAT32"
+              }
+            }
+          }
+        }
+      },
+      "propertyTables" : [ {
+        "name" : "Example property table",
+        "class" : "exampleMetadataClass",
+        "count" : 4,
+        "properties" : {
+          "example_VEC3_FLOAT32" : {
+            "values" : 4
+          }
+        }
+      } ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_mesh_features", "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5120,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 123 ],
+    "min" : [ -123 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,AAABAAIAAQADAAIABAAFAAYABQAHAAYACAAJAAoACQALAAoADAANAA4ADQAPAA4AAAAAAAAAAAAAAAAAZmbmPgAAAAAAAAAAAAAAAGZm5j4AAAAAZmbmPmZm5j4AAAAAzcwMPwAAAAAAAAAAAACAPwAAAAAAAAAAzcwMP2Zm5j4AAAAAAACAP2Zm5j4AAAAAAAAAAM3MDD8AAAAAZmbmPs3MDD8AAAAAAAAAAAAAgD8AAAAAZmbmPgAAgD8AAAAAzcwMP83MDD8AAAAAAACAP83MDD8AAAAAzcwMPwAAgD8AAAAAAACAPwAAgD8AAAAAAAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/AAAAAAAAAAAAAIA/hQAAAIUAAACFAAAAhQAAAAEAAAABAAAAAQAAAAEAAAACAAAAAgAAAAIAAAACAAAAewAAAHsAAAB7AAAAewAAAA==",
+    "byteLength" : 496
+  }, {
+    "uri" : "data:application/gltf-buffer;base64,AAAAAM3MzD3NzEw+AACAP83MjD+amZk/AAAAQGZmBkDNzAxAAABAQGZmRkDNzExA",
+    "byteLength" : 48
+  } ],
+  "bufferViews" : [ {
+    "buffer" : 0,
+    "byteOffset" : 0,
+    "byteLength" : 48,
+    "target" : 34963
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  }, {
+    "buffer" : 1,
+    "byteOffset" : 0,
+    "byteLength" : 48
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 4,
+            "attribute" : 0,
+            "propertyTable" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/FeatureIdAttributePropertyTableInvalidValue.gltf

@@ -0,0 +1,141 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "FeatureIdAttributeAndPropertyTableSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class",
+            "properties" : {
+              "example_VEC3_FLOAT32" : {
+                "name" : "Example VEC3 FLOAT32 property",
+                "description" : "An example property, with type VEC3, with component type FLOAT32",
+                "type" : "VEC3",
+                "componentType" : "FLOAT32"
+              }
+            }
+          }
+        }
+      },
+      "propertyTables" : [ {
+        "name" : "Example property table",
+        "class" : "exampleMetadataClass",
+        "count" : 4,
+        "properties" : {
+          "example_VEC3_FLOAT32" : {
+            "values" : 4
+          }
+        }
+      } ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_mesh_features", "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
+    "byteLength" : 496
+  }, {
+    "uri" : "data:application/gltf-buffer;base64,AAAAAM3MzD3NzEw+AACAP83MjD+amZk/AAAAQGZmBkDNzAxAAABAQGZmRkDNzExA",
+    "byteLength" : 48
+  } ],
+  "bufferViews" : [ {
+    "buffer" : 0,
+    "byteOffset" : 0,
+    "byteLength" : 48,
+    "target" : 34963
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  }, {
+    "buffer" : 1,
+    "byteOffset" : 0,
+    "byteLength" : 48
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 4,
+            "attribute" : 0,
+            "propertyTable" : 12345
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/FeatureIdAttributePropertyTableWithoutPropertyTables.gltf

@@ -0,0 +1,131 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "FeatureIdAttributeAndPropertyTableSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class",
+            "properties" : {
+              "example_VEC3_FLOAT32" : {
+                "name" : "Example VEC3 FLOAT32 property",
+                "description" : "An example property, with type VEC3, with component type FLOAT32",
+                "type" : "VEC3",
+                "componentType" : "FLOAT32"
+              }
+            }
+          }
+        }
+      } 
+    }
+  },
+  "extensionsUsed" : [ "EXT_mesh_features", "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
+    "byteLength" : 496
+  }, {
+    "uri" : "data:application/gltf-buffer;base64,AAAAAM3MzD3NzEw+AACAP83MjD+amZk/AAAAQGZmBkDNzAxAAABAQGZmRkDNzExA",
+    "byteLength" : 48
+  } ],
+  "bufferViews" : [ {
+    "buffer" : 0,
+    "byteOffset" : 0,
+    "byteLength" : 48,
+    "target" : 34963
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  }, {
+    "buffer" : 1,
+    "byteOffset" : 0,
+    "byteLength" : 48
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 4,
+            "attribute" : 0,
+            "propertyTable" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/FeatureIdAttributePropertyTableWithoutStructuralMetadata.gltf

@@ -0,0 +1,110 @@
+{
+  "extensionsUsed" : [ "EXT_mesh_features" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
+    "byteLength" : 496
+  }, {
+    "uri" : "data:application/gltf-buffer;base64,AAAAAM3MzD3NzEw+AACAP83MjD+amZk/AAAAQGZmBkDNzAxAAABAQGZmRkDNzExA",
+    "byteLength" : 48
+  } ],
+  "bufferViews" : [ {
+    "buffer" : 0,
+    "byteOffset" : 0,
+    "byteLength" : 48,
+    "target" : 34963
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  }, {
+    "buffer" : 1,
+    "byteOffset" : 0,
+    "byteLength" : 48
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 4,
+            "attribute" : 0,
+            "propertyTable" : 12345
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/README.md

@@ -0,0 +1,14 @@
+# Test fixtures
+
+This directory contains glTF files used for testing 3D Tiles functionality.
+
+3D Tiles Test fixtures are obtained from https://github.com/CesiumGS/3d-tiles-validator/tree/main/specs/data/gltfExtensions
+
+## Validating
+
+The files can be validated using the 3D Tiles Validator:
+
+```
+$ git clone https://github.com/CesiumGS/3d-tiles-validator
+$ npx ts-node  ./3d-tiles-validator/src/main.ts --tileContentFile test.gltf
+```

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/ValidFeatureIdAttributeAndPropertyTable.gltf

@@ -0,0 +1,141 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "FeatureIdAttributeAndPropertyTableSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class",
+            "properties" : {
+              "example_VEC3_FLOAT32" : {
+                "name" : "Example VEC3 FLOAT32 property",
+                "description" : "An example property, with type VEC3, with component type FLOAT32",
+                "type" : "VEC3",
+                "componentType" : "FLOAT32"
+              }
+            }
+          }
+        }
+      },
+      "propertyTables" : [ {
+        "name" : "Example property table",
+        "class" : "exampleMetadataClass",
+        "count" : 4,
+        "properties" : {
+          "example_VEC3_FLOAT32" : {
+            "values" : 4
+          }
+        }
+      } ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_mesh_features", "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/instanceFeatures/InstanceFeaturesFeatureIdAttributeInvalidValue.gltf

@@ -0,0 +1,179 @@
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/instanceFeatures/InstanceFeaturesWithoutMeshGpuInstancing.gltf

@@ -0,0 +1,171 @@
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+        "properties" : {
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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/instanceFeatures/ValidInstanceFeatures.gltf

@@ -0,0 +1,179 @@
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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeAccessorNormalized.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeAccessorNotScalar.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeAttributeInvalidType.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeAttributeInvalidValue.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeFeatureCountInvalidType.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeFeatureCountInvalidValue.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeFeatureCountMismatch.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeFeatureCountMismatchForNullFeatureId.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeFeatureCountMissing.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeLabelInvalidType.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeLabelInvalidValue.gltf

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+    "uri" : "data:application/gltf-buffer;base64,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",
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+    "byteStride" : 4,
+    "target" : 34962
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "label": "NOT:A:VALID/IDENTIFIER",
+            "featureCount" : 4,
+            "attribute" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeNullFeatureIdInvalidType.gltf

@@ -0,0 +1,103 @@
+{
+  "extensionsUsed" : [ "EXT_mesh_features" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
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+  } ],
+  "bufferViews" : [ {
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+    "target" : 34962
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+    "byteLength" : 192,
+    "target" : 34962
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+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "nullFeatureId": "NOT_A_NUMBER",
+            "featureCount" : 4,
+            "attribute" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/FeatureIdAttributeNullFeatureIdInvalidValue.gltf

@@ -0,0 +1,103 @@
+{
+  "extensionsUsed" : [ "EXT_mesh_features" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
+    "byteLength" : 496
+  } ],
+  "bufferViews" : [ {
+    "buffer" : 0,
+    "byteOffset" : 0,
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+    "target" : 34963
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "nullFeatureId": -12345,
+            "featureCount" : 4,
+            "attribute" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/README.md

@@ -0,0 +1,19 @@
+
+
+The files in this directory are used for the specs for the `EXT_mesh_features`
+validation.
+
+The valid files have been taken from
+https://github.com/CesiumGS/3d-tiles-samples/tree/a256d9f68df15bbfc75ea3891f52c72a36d04202/glTF/EXT_mesh_features
+
+The `ValidFeatureIdTexture.glb` and `ValidFeatureIdAttributeDefault/` are 
+intended for basic tests of binary- and default (non-embedded) glTF assets. 
+
+The `ValidFeatureIdAttributeWithByteStride.glb` was created from the original
+`ValidFeatureIdTexture.gltf` by passing it through https://gltf.report/ , which 
+happens to write all attributes in an interleaved way, causing a byte stride 
+to be inserted. 
+
+The other files (starting with `FeatureIdTexture*` or `FeatureIdAttribute*`)
+have been edited to cause validation errors (with the error indicated by 
+their file name, as far as reasonably possible). 

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/ValidFeatureIdAttribute.gltf

@@ -0,0 +1,102 @@
+{
+  "extensionsUsed" : [ "EXT_mesh_features" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
+    "byteLength" : 496
+  } ],
+  "bufferViews" : [ {
+    "buffer" : 0,
+    "byteOffset" : 0,
+    "byteLength" : 48,
+    "target" : 34963
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 4,
+            "attribute" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/ValidFeatureIdAttributeDefault/ValidFeatureIdAttributeDefault.gltf

@@ -0,0 +1,159 @@
+{
+  "extensionsUsed": [
+    "EXT_mesh_features"
+  ],
+  "accessors": [
+    {
+      "bufferView": 0,
+      "byteOffset": 0,
+      "componentType": 5123,
+      "count": 24,
+      "type": "SCALAR",
+      "max": [
+        15
+      ],
+      "min": [
+        0
+      ]
+    },
+    {
+      "bufferView": 1,
+      "byteOffset": 0,
+      "componentType": 5126,
+      "count": 16,
+      "type": "VEC3",
+      "max": [
+        1,
+        1,
+        0
+      ],
+      "min": [
+        0,
+        0,
+        0
+      ]
+    },
+    {
+      "bufferView": 2,
+      "byteOffset": 0,
+      "componentType": 5126,
+      "count": 16,
+      "type": "VEC3",
+      "max": [
+        0,
+        0,
+        1
+      ],
+      "min": [
+        0,
+        0,
+        1
+      ]
+    },
+    {
+      "bufferView": 3,
+      "byteOffset": 0,
+      "componentType": 5121,
+      "count": 16,
+      "type": "SCALAR",
+      "max": [
+        3
+      ],
+      "min": [
+        0
+      ]
+    }
+  ],
+  "asset": {
+    "generator": "JglTF from https://github.com/javagl/JglTF",
+    "version": "2.0"
+  },
+  "buffers": [
+    {
+      "uri": "ValidFeatureIdAttributeDefault_data.bin",
+      "byteLength": 496
+    }
+  ],
+  "bufferViews": [
+    {
+      "buffer": 0,
+      "byteOffset": 0,
+      "byteLength": 48,
+      "target": 34963
+    },
+    {
+      "buffer": 0,
+      "byteOffset": 48,
+      "byteLength": 192,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteOffset": 240,
+      "byteLength": 192,
+      "target": 34962
+    },
+    {
+      "buffer": 0,
+      "byteOffset": 432,
+      "byteLength": 64,
+      "byteStride": 4,
+      "target": 34962
+    }
+  ],
+  "materials": [
+    {
+      "pbrMetallicRoughness": {
+        "baseColorFactor": [
+          0.5,
+          1,
+          0.5,
+          1
+        ],
+        "metallicFactor": 0,
+        "roughnessFactor": 1
+      },
+      "alphaMode": "OPAQUE",
+      "doubleSided": true
+    }
+  ],
+  "meshes": [
+    {
+      "primitives": [
+        {
+          "extensions": {
+            "EXT_mesh_features": {
+              "featureIds": [
+                {
+                  "featureCount": 4,
+                  "attribute": 0
+                }
+              ]
+            }
+          },
+          "attributes": {
+            "POSITION": 1,
+            "NORMAL": 2,
+            "_FEATURE_ID_0": 3
+          },
+          "indices": 0,
+          "material": 0,
+          "mode": 4
+        }
+      ]
+    }
+  ],
+  "nodes": [
+    {
+      "mesh": 0
+    }
+  ],
+  "scene": 0,
+  "scenes": [
+    {
+      "nodes": [
+        0
+      ]
+    }
+  ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/ValidFeatureIdAttributeWithLargerFeatureCount.gltf

@@ -0,0 +1,102 @@
+{
+  "extensionsUsed" : [ "EXT_mesh_features" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
+    "bufferView" : 3,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
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+  } ],
+  "bufferViews" : [ {
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+    "target" : 34963
+  }, {
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+    "byteOffset" : 48,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 240,
+    "byteLength" : 192,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
+    "byteOffset" : 432,
+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 123,
+            "attribute" : 0
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/meshFeatures/ValidFeatureIdAttributeWithNullFeatureId.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/ExtensionInMeshPrimitiveWithoutTopLevelObject.gltf

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tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesClassPropertyArray.gltf

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+        "_CLASSIFICATION" : 14
+      },
+      "indices" : 10,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesClassPropertyInvalidComponentType.gltf

@@ -0,0 +1,327 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType": "FLOAT64"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      } ]
+    }
+  },
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+  } ],
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+  },
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+  "materials" : [ {
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+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyAttributes" : [ 0 ]
+        }
+      },
+      "attributes" : {
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+        "NORMAL" : 2,
+        "_INTENSITY" : 3,
+        "_CLASSIFICATION" : 4
+      },
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+      "material" : 0,
+      "mode" : 4
+    }, {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyAttributes" : [ 0 ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 6,
+        "NORMAL" : 7,
+        "_INTENSITY" : 8,
+        "_CLASSIFICATION" : 9
+      },
+      "indices" : 5,
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+    }, {
+      "extensions" : {
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+          "propertyAttributes" : [ 0 ]
+        }
+      },
+      "attributes" : {
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+        "NORMAL" : 12,
+        "_INTENSITY" : 13,
+        "_CLASSIFICATION" : 14
+      },
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+      "material" : 0,
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+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesClassPropertyInvalidEnumValueType.gltf

@@ -0,0 +1,328 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType": "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "valueType": "INT64",
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      } ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 6,
+    "type" : "SCALAR",
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+    "min" : [ 0 ]
+  }, {
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+    "type" : "VEC3",
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+    "min" : [ -1.0, 0.0, 0.0 ]
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+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
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+  } ],
+  "asset" : {
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+    "version" : "2.0"
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+      },
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+  "scene" : 0,
+  "scenes" : [ {
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+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesClassPropertyMaxNotInRange.gltf

@@ -0,0 +1,339 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32",
+                "max": 0.7
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }, {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesClassPropertyMinNotInRange.gltf

@@ -0,0 +1,339 @@
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+        "classes" : {
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+            "description" : "An example metadata class for property attributes",
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+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32",
+                "min": 0.3
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+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
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+              "value" : 2
+            } ]
+          }
+        }
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+          }
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesClassPropertyString.gltf

@@ -0,0 +1,326 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "STRING"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      } ]
+    }
+  },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesMeshPrimitivePropertyAttributesInvalidElementType.gltf

@@ -0,0 +1,327 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
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+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
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+        "class" : "exampleMetadataClass",
+        "properties" : {
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+          },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesMeshPrimitivePropertyAttributesInvalidElementValue.gltf

@@ -0,0 +1,327 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      } ]
+    }
+  },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesMeshPrimitivePropertyAttributesInvalidLength.gltf

@@ -0,0 +1,327 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
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+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
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+        "properties" : {
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesMeshPrimitivePropertyAttributesInvalidType.gltf

@@ -0,0 +1,327 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      } ]
+    }
+  },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesPropertyAttributePropertyInvalidAttribute.gltf

@@ -0,0 +1,327 @@
+{
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+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
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+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
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+            "attribute" : "THIS_ATTRIBUTE_DOES_NOT_EXIST"
+          },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesPropertyAttributePropertyMaxMismatch.gltf

@@ -0,0 +1,339 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
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+            "attribute" : "_INTENSITY",
+            "max": 0.3
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }, {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
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+          }
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+      "mode" : 4
+    }, {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyAttributes" : [ 1 ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 11,
+        "NORMAL" : 12,
+        "_INTENSITY" : 13,
+        "_CLASSIFICATION" : 14
+      },
+      "indices" : 10,
+      "material" : 0,
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+    } ]
+  } ],
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+  } ],
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+  "scenes" : [ {
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+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesPropertyAttributePropertyMaxNotInRange.gltf

@@ -0,0 +1,339 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY",
+            "max": 0.2
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }, {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }
+      ]
+    }
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+        "_CLASSIFICATION" : 4
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+    }, {
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+        }
+      },
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+      },
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+  } ],
+  "scene" : 0,
+  "scenes" : [ {
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+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesPropertyAttributePropertyMinMismatch.gltf

@@ -0,0 +1,339 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY",
+            "min": 0.2
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }, {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }
+      ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_structural_metadata" ],
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyAttributesPropertyAttributePropertyMinNotInRange.gltf

@@ -0,0 +1,339 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY",
+            "min": 0.3
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }, {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      }
+      ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_structural_metadata" ],
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+    "byteLength" : 16,
+    "byteStride" : 4,
+    "target" : 34962
+  } ],
+  "materials" : [ {
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+      "baseColorFactor" : [ 1.0, 1.0, 1.0, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyAttributes" : [ 0 ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_INTENSITY" : 3,
+        "_CLASSIFICATION" : 4
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    }, {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyAttributes" : [ 1 ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 6,
+        "NORMAL" : 7,
+        "_INTENSITY" : 8,
+        "_CLASSIFICATION" : 9
+      },
+      "indices" : 5,
+      "material" : 0,
+      "mode" : 4
+    }, {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyAttributes" : [ 1 ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 11,
+        "NORMAL" : 12,
+        "_INTENSITY" : 13,
+        "_CLASSIFICATION" : 14
+      },
+      "indices" : 10,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/PropertyTextureEnumsInvalidEnumValue.gltf

@@ -0,0 +1,176 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "PropertyTextureEnumsSchemaId",
+        "classes" : {
+          "propertyTextureEnumsClass" : {
+            "name" : "Property texture example enum properties",
+            "properties" : {
+              "enumProperty" : {
+                "name" : "Example enum property",
+                "type" : "ENUM",
+                "enumType" : "exampleEnum",
+                "noData" : "NO_DATA_ENUM_VALUE",
+                "default" : "DEFAULT_ENUM_VALUE"
+              },
+              "enumArrayProperty" : {
+                "name" : "Example enum array property",
+                "type" : "ENUM",
+                "enumType" : "exampleEnum",
+                "array" : true,
+                "count" : 2,
+                "noData" : [ "NO_DATA_ENUM_VALUE", "NO_DATA_ENUM_VALUE" ],
+                "default" : [ "DEFAULT_ENUM_VALUE", "DEFAULT_ENUM_VALUE" ]
+              }
+            }
+          }
+        },
+        "enums" : {
+          "exampleEnum" : {
+            "valueType": "UINT8",
+            "values" : [ {
+              "name" : "NO_DATA_ENUM_VALUE",
+              "value" : 255
+            }, {
+              "name" : "EXAMPLE_ENUM_VALUE_A",
+              "value" : 0
+            }, {
+              "name" : "EXAMPLE_ENUM_VALUE_B",
+              "value" : 1
+            }, {
+              "name" : "EXAMPLE_ENUM_VALUE_C",
+              "value" : 2
+            }, {
+              "name" : "DEFAULT_ENUM_VALUE",
+              "value" : 3
+            } ]
+          }
+        }
+      },
+      "propertyTextures" : [ {
+        "class" : "propertyTextureEnumsClass",
+        "properties" : {
+          "enumProperty" : {
+            "index" : 0,
+            "texCoord" : 0,
+            "channels" : [ 0 ]
+          },
+          "enumArrayProperty" : {
+            "index" : 0,
+            "texCoord" : 0,
+            "channels" : [ 1, 2 ]
+          }
+        }
+      } ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 6,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  }, {
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+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 4,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
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+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 4,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
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+    "byteOffset" : 0,
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+    "count" : 4,
+    "type" : "VEC2",
+    "max" : [ 1.0, 1.0 ],
+    "min" : [ 0.0, 0.0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
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+    "byteLength" : 140
+  } ],
+  "bufferViews" : [ {
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+  }, {
+    "buffer" : 0,
+    "byteOffset" : 108,
+    "byteLength" : 32,
+    "target" : 34962
+  } ],
+  "images" : [ {
+    "uri" : "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAYAAABytg0kAAAAGUlEQVR42mP4/5/hPwMTAwNDSgpDCpBmAgA21QQw4gn1GgAAAABJRU5ErkJggg==",
+    "mimeType" : "image/png"
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 0.5, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_structural_metadata" : {
+          "propertyTextures" : [ 0 ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "TEXCOORD_0" : 3
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "samplers" : [ {
+    "magFilter" : 9728,
+    "minFilter" : 9728
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ],
+  "textures" : [ {
+    "sampler" : 0,
+    "source" : 0
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/README.md

@@ -0,0 +1,21 @@
+The files in this directory are used for the specs for the 
+`EXT_structural_metadata` validation.
+
+The valid files have been taken from
+https://github.com/CesiumGS/3d-tiles-samples/tree/a256d9f68df15bbfc75ea3891f52c72a36d04202/glTF/EXT_structural_metadata
+except for the following ones, which have been created dedicatedly for these tests:
+
+- `ValidPropertyAttributes.gltf`
+- `ValidPropertyTextureEnums.gltf`
+
+The files that cause issues have been created by modifying these files 
+This mostly happened manually, with the exception of certain invalid values in 
+property textures, that have been written out in this form by the generator.
+
+Note that some parts of the validation specs are not covered here, because
+they are covered by the main 3D Tiles Validator specs. Particularly:
+
+- Validation of the metadata schema is covered with `./specs/data/schemas/`
+- Validation of the property tables is covered with `./specs/data/subtrees/subtreePropertyTables*.json`
+
+

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/StructuralMetadataMissingSchema.gltf

@@ -0,0 +1,173 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "propertyTables" : [ {
+        "name" : "First example property table",
+        "class" : "exampleMetadataClassA",
+        "count" : 4,
+        "properties" : {
+          "example_FLOAT32" : {
+            "values" : 5
+          },
+          "example_INT64" : {
+            "values" : 6
+          }
+        }
+      }, {
+        "name" : "Second example property table",
+        "class" : "exampleMetadataClassB",
+        "count" : 4,
+        "properties" : {
+          "example_UINT16" : {
+            "values" : 7
+          },
+          "example_FLOAT64" : {
+            "values" : 8
+          }
+        }
+      } ]
+    }
+  },
+  "extensionsUsed" : [ "EXT_mesh_features", "EXT_structural_metadata" ],
+  "accessors" : [ {
+    "bufferView" : 0,
+    "byteOffset" : 0,
+    "componentType" : 5123,
+    "count" : 24,
+    "type" : "SCALAR",
+    "max" : [ 15 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 1,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 1.0, 1.0, 0.0 ],
+    "min" : [ 0.0, 0.0, 0.0 ]
+  }, {
+    "bufferView" : 2,
+    "byteOffset" : 0,
+    "componentType" : 5126,
+    "count" : 16,
+    "type" : "VEC3",
+    "max" : [ 0.0, 0.0, 1.0 ],
+    "min" : [ 0.0, 0.0, 1.0 ]
+  }, {
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+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  }, {
+    "bufferView" : 4,
+    "byteOffset" : 0,
+    "componentType" : 5121,
+    "count" : 16,
+    "type" : "SCALAR",
+    "max" : [ 3 ],
+    "min" : [ 0 ]
+  } ],
+  "asset" : {
+    "generator" : "JglTF from https://github.com/javagl/JglTF",
+    "version" : "2.0"
+  },
+  "buffers" : [ {
+    "uri" : "data:application/gltf-buffer;base64,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",
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+  }, {
+    "uri" : "data:application/gltf-buffer;base64,zcyMP83MDEAzM1NAzcyMQIfWEgAAAAAAzsojAAAAAAAVvzQAAAAAAFKzRQAAAAAA",
+    "byteLength" : 48
+  }, {
+    "uri" : "data:application/gltf-buffer;base64,OTCgWweHbrKHiJtTycDzP9GSx9PywwJAX2HB/YCnC0Da5sb0hEUSQA==",
+    "byteLength" : 40
+  } ],
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+  }, {
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+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  }, {
+    "buffer" : 0,
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+    "byteLength" : 64,
+    "byteStride" : 4,
+    "target" : 34962
+  }, {
+    "buffer" : 1,
+    "byteOffset" : 0,
+    "byteLength" : 16
+  }, {
+    "buffer" : 1,
+    "byteOffset" : 16,
+    "byteLength" : 32
+  }, {
+    "buffer" : 2,
+    "byteOffset" : 0,
+    "byteLength" : 8
+  }, {
+    "buffer" : 2,
+    "byteOffset" : 8,
+    "byteLength" : 32
+  } ],
+  "materials" : [ {
+    "pbrMetallicRoughness" : {
+      "baseColorFactor" : [ 0.5, 1.0, 0.5, 1.0 ],
+      "metallicFactor" : 0.0,
+      "roughnessFactor" : 1.0
+    },
+    "alphaMode" : "OPAQUE",
+    "doubleSided" : true
+  } ],
+  "meshes" : [ {
+    "primitives" : [ {
+      "extensions" : {
+        "EXT_mesh_features" : {
+          "featureIds" : [ {
+            "featureCount" : 4,
+            "attribute" : 0,
+            "propertyTable" : 0
+          }, {
+            "featureCount" : 4,
+            "attribute" : 1,
+            "propertyTable" : 1
+          } ]
+        }
+      },
+      "attributes" : {
+        "POSITION" : 1,
+        "NORMAL" : 2,
+        "_FEATURE_ID_0" : 3,
+        "_FEATURE_ID_1" : 4
+      },
+      "indices" : 0,
+      "material" : 0,
+      "mode" : 4
+    } ]
+  } ],
+  "nodes" : [ {
+    "mesh" : 0
+  } ],
+  "scene" : 0,
+  "scenes" : [ {
+    "nodes" : [ 0 ]
+  } ]
+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/StructuralMetadataSchemaAndSchemaUri.gltf

@@ -0,0 +1,229 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schemaUri": "uriToCreateValidationError.json",
+      "schema" : {
+        "id": "MultipleClassesSchema",
+        "classes" : {
+          "exampleMetadataClassA" : {
+            "name" : "Example metadata class A",
+            "description" : "First example metadata class",
+            "properties" : {
+              "example_FLOAT32" : {
+                "name" : "Example FLOAT32 property",
+                "description" : "An example property, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "example_INT64" : {
+                "name" : "Example INT64 property",
+                "description" : "An example property, with component type INT64",
+                "type" : "SCALAR",
+                "componentType" : "INT64"
+              }
+            }
+          },
+          "exampleMetadataClassB" : {
+            "name" : "Example metadata class B",
+            "description" : "Second example metadata class",
+            "properties" : {
+              "example_UINT16" : {
+                "name" : "Example UINT16 property",
+                "description" : "An example property, with component type UINT16",
+                "type" : "SCALAR",
+                "componentType" : "UINT16"
+              },
+              "example_FLOAT64" : {
+                "name" : "Example FLOAT64 property",
+                "description" : "An example property, with component type FLOAT64",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT64"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "exampleEnumType" : {
+            "values" : [ {
+              "name" : "ExampleEnumValueA",
+              "value" : 0
+            }, {
+              "name" : "ExampleEnumValueB",
+              "value" : 1
+            }, {
+              "name" : "ExampleEnumValueC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyTables" : [ {
+        "name" : "First example property table",
+        "class" : "exampleMetadataClassA",
+        "count" : 4,
+        "properties" : {
+          "example_FLOAT32" : {
+            "values" : 5
+          },
+          "example_INT64" : {
+            "values" : 6
+          }
+        }
+      }, {
+        "name" : "Second example property table",
+        "class" : "exampleMetadataClassB",
+        "count" : 4,
+        "properties" : {
+          "example_UINT16" : {
+            "values" : 7
+          },
+          "example_FLOAT64" : {
+            "values" : 8
+          }
+        }
+      } ]
+    }
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/ValidMultipleClasses.gltf

@@ -0,0 +1,228 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "MultipleClassesSchema",
+        "classes" : {
+          "exampleMetadataClassA" : {
+            "name" : "Example metadata class A",
+            "description" : "First example metadata class",
+            "properties" : {
+              "example_FLOAT32" : {
+                "name" : "Example FLOAT32 property",
+                "description" : "An example property, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "example_INT64" : {
+                "name" : "Example INT64 property",
+                "description" : "An example property, with component type INT64",
+                "type" : "SCALAR",
+                "componentType" : "INT64"
+              }
+            }
+          },
+          "exampleMetadataClassB" : {
+            "name" : "Example metadata class B",
+            "description" : "Second example metadata class",
+            "properties" : {
+              "example_UINT16" : {
+                "name" : "Example UINT16 property",
+                "description" : "An example property, with component type UINT16",
+                "type" : "SCALAR",
+                "componentType" : "UINT16"
+              },
+              "example_FLOAT64" : {
+                "name" : "Example FLOAT64 property",
+                "description" : "An example property, with component type FLOAT64",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT64"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "exampleEnumType" : {
+            "values" : [ {
+              "name" : "ExampleEnumValueA",
+              "value" : 0
+            }, {
+              "name" : "ExampleEnumValueB",
+              "value" : 1
+            }, {
+              "name" : "ExampleEnumValueC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyTables" : [ {
+        "name" : "First example property table",
+        "class" : "exampleMetadataClassA",
+        "count" : 4,
+        "properties" : {
+          "example_FLOAT32" : {
+            "values" : 5
+          },
+          "example_INT64" : {
+            "values" : 6
+          }
+        }
+      }, {
+        "name" : "Second example property table",
+        "class" : "exampleMetadataClassB",
+        "count" : 4,
+        "properties" : {
+          "example_UINT16" : {
+            "values" : 7
+          },
+          "example_FLOAT64" : {
+            "values" : 8
+          }
+        }
+      } ]
+    }
+  },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/ValidPropertyAttributes.gltf

@@ -0,0 +1,327 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "SimplePropertyAttributeSchema",
+        "classes" : {
+          "exampleMetadataClass" : {
+            "name" : "Example metadata class",
+            "description" : "An example metadata class for property attributes",
+            "properties" : {
+              "intensity" : {
+                "name" : "Example intensity property",
+                "description" : "An example property for the intensity, with component type FLOAT32",
+                "type" : "SCALAR",
+                "componentType" : "FLOAT32"
+              },
+              "classification" : {
+                "name" : "Example classification property",
+                "description" : "An example property for the classification, with the classificationEnumType",
+                "type" : "ENUM",
+                "enumType" : "classificationEnumType"
+              }
+            }
+          }
+        },
+        "enums" : {
+          "classificationEnumType" : {
+            "values" : [ {
+              "name" : "ExampleClassificationA",
+              "value" : 0
+            }, {
+              "name" : "ExampleClassificationB",
+              "value" : 1
+            }, {
+              "name" : "ExampleClassificationC",
+              "value" : 2
+            } ]
+          }
+        }
+      },
+      "propertyAttributes" : [ {
+        "class" : "exampleMetadataClass",
+        "properties" : {
+          "intensity" : {
+            "attribute" : "_INTENSITY"
+          },
+          "classification" : {
+            "attribute" : "_CLASSIFICATION"
+          }
+        }
+      } ]
+    }
+  },
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+}

tests/SharpGLTF.Ext.3DTiles.Tests/TestFixtures/structuralMetadata/ValidPropertyTextureEnums.gltf

@@ -0,0 +1,176 @@
+{
+  "extensions" : {
+    "EXT_structural_metadata" : {
+      "schema" : {
+        "id": "PropertyTextureEnumsSchemaId",
+        "classes" : {
+          "propertyTextureEnumsClass" : {
+            "name" : "Property texture example enum properties",
+            "properties" : {
+              "enumProperty" : {
+                "name" : "Example enum property",
+                "type" : "ENUM",
+                "enumType" : "exampleEnum",
+                "noData" : "NO_DATA_ENUM_VALUE",
+                "default" : "DEFAULT_ENUM_VALUE"
+              },
+              "enumArrayProperty" : {
+                "name" : "Example enum array property",
+                "type" : "ENUM",
+                "enumType" : "exampleEnum",
+                "array" : true,
+                "count" : 2,
+                "noData" : [ "NO_DATA_ENUM_VALUE", "NO_DATA_ENUM_VALUE" ],
+                "default" : [ "DEFAULT_ENUM_VALUE", "DEFAULT_ENUM_VALUE" ]
+              }
+            }
+          }
+        },
+        "enums" : {
+          "exampleEnum" : {
+            "valueType": "UINT8",
+            "values" : [ {
+              "name" : "NO_DATA_ENUM_VALUE",
+              "value" : 255
+            }, {
+              "name" : "EXAMPLE_ENUM_VALUE_A",
+              "value" : 0
+            }, {
+              "name" : "EXAMPLE_ENUM_VALUE_B",
+              "value" : 1
+            }, {
+              "name" : "EXAMPLE_ENUM_VALUE_C",
+              "value" : 2
+            }, {
+              "name" : "DEFAULT_ENUM_VALUE",
+              "value" : 3
+            } ]
+          }
+        }
+      },
+      "propertyTextures" : [ {
+        "class" : "propertyTextureEnumsClass",
+        "properties" : {
+          "enumProperty" : {
+            "index" : 0,
+            "texCoord" : 0,
+            "channels" : [ 0 ]
+          },
+          "enumArrayProperty" : {
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+            "channels" : [ 1, 2 ]
+          }
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+  "images" : [ {
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+}