Add glTFv2 Clearcoat import/export tests

Uses Clearcoat model from Khronos

code/AssetLib/glTF2/glTF2Importer.cpp

@@ -208,6 +208,11 @@ inline void SetMaterialTextureProperty(std::vector<int> &embeddedTexIdxs, Asset
             if (sampler->minFilter != SamplerMinFilter::UNSET) {
                 mat->AddProperty(&sampler->minFilter, 1, AI_MATKEY_GLTF_MAPPINGFILTER_MIN(texType, texSlot));
             }
+        } else {
+            // Use glTFv2 default sampler
+            const aiTextureMapMode default_wrap = aiTextureMapMode_Wrap;
+            mat->AddProperty(&default_wrap, 1, AI_MATKEY_MAPPINGMODE_U(texType, texSlot));
+            mat->AddProperty(&default_wrap, 1, AI_MATKEY_MAPPINGMODE_V(texType, texSlot));
         }
     }
 }

include/assimp/material.h

@@ -1014,7 +1014,8 @@ extern "C" {
 
 // Clearcoat
 // ---------
-#define AI_MATKEY_CLEARCOAT_FACTOR "$clr.clearcoat.factor", 0, 0
+// Clearcoat layer intensity. 0.0 = none (disabled)
+#define AI_MATKEY_CLEARCOAT_FACTOR "$mat.clearcoat.factor", 0, 0
 #define AI_MATKEY_CLEARCOAT_ROUGHNESS_FACTOR "$mat.clearcoat.roughnessFactor", 0, 0
 #define AI_MATKEY_CLEARCOAT_TEXTURE aiTextureType_CLEARCOAT, 0
 #define AI_MATKEY_CLEARCOAT_ROUGHNESS_TEXTURE aiTextureType_CLEARCOAT, 1

test/models/glTF2/ClearCoat-glTF/ClearCoatTest.gltf

@@ -0,0 +1,1669 @@
+{
+    "asset" : {
+        "generator" : "Khronos glTF Blender I/O v1.2.8 with hand-edits for clearcoat",
+        "version" : "2.0"
+    },
+    "extensionsUsed": [
+        "KHR_materials_clearcoat"
+    ],
+    "scene" : 0,
+    "scenes" : [
+        {
+            "name" : "Scene",
+            "nodes" : [
+                3,
+                7,
+                11,
+                15,
+                19,
+                23,
+                24,
+                25,
+                26,
+                27,
+                28,
+                29,
+                30,
+                31,
+                32
+            ]
+        }
+    ],
+    "nodes" : [
+        {
+            "mesh" : 0,
+            "name" : "BaseLayerSample",
+            "translation" : [
+                -2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "mesh" : 1,
+            "name" : "ClearCoatSample"
+        },
+        {
+            "mesh" : 2,
+            "name" : "CoatOnlySample",
+            "translation" : [
+                2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "children" : [
+                0,
+                1,
+                2
+            ],
+            "name" : "R0_SimpleCoatTest",
+            "translation" : [
+                0,
+                5.25,
+                0
+            ]
+        },
+        {
+            "mesh" : 3,
+            "name" : "R1_BaseLayerSample",
+            "translation" : [
+                -2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "mesh" : 4,
+            "name" : "R1_ClearCoatSample"
+        },
+        {
+            "mesh" : 5,
+            "name" : "R1_CoatOnlySample",
+            "translation" : [
+                2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "children" : [
+                4,
+                5,
+                6
+            ],
+            "name" : "R1_PartialCoatTest",
+            "translation" : [
+                0,
+                3.1500000953674316,
+                0
+            ]
+        },
+        {
+            "mesh" : 6,
+            "name" : "R2_BaseLayerSample",
+            "translation" : [
+                -2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "mesh" : 7,
+            "name" : "R2_ClearCoatSample"
+        },
+        {
+            "mesh" : 8,
+            "name" : "R2_CoatOnlySample",
+            "translation" : [
+                2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "children" : [
+                8,
+                9,
+                10
+            ],
+            "name" : "R2_RoughnessVariations",
+            "translation" : [
+                0,
+                1.0499999523162842,
+                0
+            ]
+        },
+        {
+            "mesh" : 9,
+            "name" : "R3_BaseLayerSample",
+            "translation" : [
+                -2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "mesh" : 10,
+            "name" : "R3_ClearCoatSample"
+        },
+        {
+            "mesh" : 11,
+            "name" : "R3_CoatOnlySample",
+            "translation" : [
+                2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "children" : [
+                12,
+                13,
+                14
+            ],
+            "name" : "R3_BaseNormals",
+            "translation" : [
+                0,
+                -1.0499999523162842,
+                0
+            ]
+        },
+        {
+            "mesh" : 12,
+            "name" : "R4_BaseLayerSample",
+            "translation" : [
+                -2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "mesh" : 13,
+            "name" : "R4_ClearCoatSample"
+        },
+        {
+            "mesh" : 14,
+            "name" : "R4_CoatOnlySample",
+            "translation" : [
+                2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "children" : [
+                16,
+                17,
+                18
+            ],
+            "name" : "R4_CoatNormals",
+            "translation" : [
+                0,
+                -5.25,
+                0
+            ]
+        },
+        {
+            "mesh" : 15,
+            "name" : "R5_BaseLayerSample",
+            "translation" : [
+                -2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "mesh" : 16,
+            "name" : "R5_ClearCoatSample"
+        },
+        {
+            "mesh" : 17,
+            "name" : "R5_CoatOnlySample",
+            "translation" : [
+                2.0999999046325684,
+                0,
+                0
+            ]
+        },
+        {
+            "children" : [
+                20,
+                21,
+                22
+            ],
+            "name" : "R5_SharedNormals",
+            "translation" : [
+                0,
+                -3.1500000953674316,
+                0
+            ]
+        },
+        {
+            "mesh" : 18,
+            "name" : "X2_Label_CoatingOnly",
+            "translation" : [
+                2.0712804794311523,
+                6.619500160217285,
+                0
+            ]
+        },
+        {
+            "mesh" : 19,
+            "name" : "Y0_Label_SimpleCoating",
+            "translation" : [
+                -5.3578033447265625,
+                5.25,
+                0
+            ]
+        },
+        {
+            "mesh" : 20,
+            "name" : "Y1_Label_PartialCoating",
+            "translation" : [
+                -5.3578033447265625,
+                3.1673200130462646,
+                0
+            ]
+        },
+        {
+            "mesh" : 21,
+            "name" : "Y2_Label_Roughness",
+            "translation" : [
+                -5.3578033447265625,
+                1.1383899450302124,
+                0
+            ]
+        },
+        {
+            "mesh" : 22,
+            "name" : "Y3_Label_BaseNormals",
+            "translation" : [
+                -5.3578033447265625,
+                -1.099429965019226,
+                0
+            ]
+        },
+        {
+            "mesh" : 23,
+            "name" : "Y4_Label_CoatNormals",
+            "translation" : [
+                -5.3578033447265625,
+                -5.252500057220459,
+                0
+            ]
+        },
+        {
+            "mesh" : 24,
+            "name" : "Y5_Label_SharedNormals",
+            "translation" : [
+                -5.3578033447265625,
+                -3.1963000297546387,
+                0
+            ]
+        },
+        {
+            "mesh" : 25,
+            "name" : "X0_Label_BaseLayer",
+            "translation" : [
+                -2.087031602859497,
+                6.616230010986328,
+                0
+            ]
+        },
+        {
+            "mesh" : 26,
+            "name" : "X1_Label_Coated",
+            "translation" : [
+                0,
+                6.614150047302246,
+                0
+            ]
+        }
+    ],
+    "materials" : [
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "Simple_Base",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.5,
+                    0.019999999552965164,
+                    0.009999999776482582,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "Simple_Coated",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.5,
+                    0.019999999552965164,
+                    0.009999999776482582,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            },
+            "extensions": {
+                "KHR_materials_clearcoat": {
+                    "clearcoatFactor": 1,
+                    "clearcoatRoughnessFactor": 0.03
+                }
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "Simple_Coating",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0,
+                    0,
+                    0,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.029999999329447746
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "Partial_Base",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "Partial_Coated",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            },
+            "extensions": {
+                "KHR_materials_clearcoat": {
+                    "clearcoatFactor": 1,
+                    "clearcoatRoughnessFactor": 0.03,
+                    "clearcoatTexture": {
+                        "index": 0,
+                        "texCoord": 0
+                    }
+                }
+            }
+        },
+        {
+            "alphaMode" : "BLEND",
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "Partial_Coating",
+            "pbrMetallicRoughness" : {
+                "baseColorTexture" : {
+                    "index" : 1,
+                    "texCoord" : 0
+                },
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.029999999329447746
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "RoughVariations_Base",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.6000000238418579
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "RoughVariations_Coated",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.6000000238418579
+            },
+            "extensions": {
+                "KHR_materials_clearcoat": {
+                    "clearcoatFactor": 1,
+                    "clearcoatRoughnessFactor": 1,
+                    "clearcoatRoughnessTexture": {
+                        "index": 2,
+                        "texCoord": 0
+                    }
+                }
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "RoughVariations_Coating",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0,
+                    0,
+                    0,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "metallicRoughnessTexture" : {
+                    "index" : 2,
+                    "texCoord" : 0
+                }
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "BaseNorm_Base",
+            "normalTexture" : {
+                "index" : 3,
+                "texCoord" : 0
+            },
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "BaseNorm_Coated",
+            "normalTexture" : {
+                "index" : 4,
+                "texCoord" : 0
+            },
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012848637998104095,
+                    0.021861059591174126,
+                    0.11068868637084961,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            },
+            "extensions": {
+                "KHR_materials_clearcoat": {
+                    "clearcoatFactor": 1,
+                    "clearcoatRoughnessFactor": 0.03
+                }
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "BaseNorm_Coating",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0,
+                    0,
+                    0,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.029999999329447746
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "CoatNorm_Base",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "CoatNorm_Coated",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            },
+            "extensions": {
+                "KHR_materials_clearcoat": {
+                    "clearcoatFactor": 1,
+                    "clearcoatRoughnessFactor": 0.03,
+                    "clearcoatNormalTexture": {
+                        "index": 5,
+                        "texCoord": 0,
+                        "scale": 1
+                    }
+                }
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "CoatNorm_Coating",
+            "normalTexture" : {
+                "index" : 5,
+                "texCoord" : 0
+            },
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0,
+                    0,
+                    0,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.029999999329447746
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "SharedNorm_Base",
+            "normalTexture" : {
+                "index" : 6,
+                "texCoord" : 0
+            },
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "SharedNorm_Coated",
+            "normalTexture" : {
+                "index" : 7,
+                "texCoord" : 0
+            },
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0.012983020395040512,
+                    0.022173883393406868,
+                    0.10946174710988998,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.4399999976158142
+            },
+            "extensions": {
+                "KHR_materials_clearcoat": {
+                    "clearcoatFactor": 1,
+                    "clearcoatRoughnessFactor": 0.03,
+                    "clearcoatNormalTexture": {
+                        "index": 7,
+                        "texCoord": 0
+                    }
+                }
+            }
+        },
+        {
+            "emissiveFactor" : [
+                0,
+                0,
+                0
+            ],
+            "name" : "SharedNorm_Coating",
+            "normalTexture" : {
+                "index" : 8,
+                "texCoord" : 0
+            },
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0,
+                    0,
+                    0,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.029999999329447746
+            }
+        },
+        {
+            "emissiveFactor" : [
+                1,
+                1,
+                1
+            ],
+            "emissiveTexture" : {
+                "index" : 9,
+                "texCoord" : 0
+            },
+            "name" : "LabelMaterial",
+            "pbrMetallicRoughness" : {
+                "baseColorFactor" : [
+                    0,
+                    0,
+                    0,
+                    1
+                ],
+                "metallicFactor" : 0,
+                "roughnessFactor" : 0.8999999761581421
+            }
+        }
+    ],
+    "meshes" : [
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 0
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 1
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 2
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 3
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 4
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 5
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 6
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 7
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
+            "primitives" : [
+                {
+                    "attributes" : {
+                        "POSITION" : 0,
+                        "NORMAL" : 1,
+                        "TEXCOORD_0" : 2
+                    },
+                    "indices" : 3,
+                    "material" : 8
+                }
+            ]
+        },
+        {
+            "name" : "ClearCoatSampleMesh",
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+            ]
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+    ],
+    "textures" : [
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+        },
+        {
+            "source" : 5
+        }
+    ],
+    "images" : [
+        {
+            "mimeType" : "image/png",
+            "name" : "PartialCoating",
+            "uri" : "PartialCoating.png"
+        },
+        {
+            "mimeType" : "image/png",
+            "name" : "PartialCoating_Alpha",
+            "uri" : "PartialCoating_Alpha.png"
+        },
+        {
+            "mimeType" : "image/png",
+            "name" : "RoughnessStripes",
+            "uri" : "RoughnessStripes.png"
+        },
+        {
+            "mimeType" : "image/png",
+            "name" : "RibsNormal",
+            "uri" : "RibsNormal.png"
+        },
+        {
+            "mimeType" : "image/jpeg",
+            "name" : "PlasticWrap_normals",
+            "uri" : "PlasticWrap_normals.jpg"
+        },
+        {
+            "mimeType" : "image/png",
+            "name" : "ClearCoatLabels",
+            "uri" : "ClearCoatLabels.png"
+        }
+    ],
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+    "buffers" : [
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+    ]
+}

test/unit/utglTF2ImportExport.cpp

@@ -151,8 +151,65 @@ TEST_F(utglTF2ImportExport, importglTF2_KHR_materials_pbrSpecularGlossiness) {
     EXPECT_TRUE(importerMatTest(ASSIMP_TEST_MODELS_DIR "/glTF2/BoxTextured-glTF-pbrSpecularGlossiness/BoxTextured.gltf", true));
 }
 
+void VerifyClearCoatScene(const aiScene *scene) {
+        ASSERT_NE(nullptr, scene);
+
+    ASSERT_TRUE(scene->HasMaterials());
+
+    // Find a specific Clearcoat material and check the values
+    const aiString partial_coated("Partial_Coated");
+    bool found_partial_coat = false;
+    for (size_t i = 0; i < scene->mNumMaterials; ++i) {
+        const aiMaterial *material = scene->mMaterials[i];
+        ASSERT_NE(nullptr, material);
+        if (material->GetName() == partial_coated) {
+            found_partial_coat = true;
+
+            ai_real clearcoat_factor(0.0f);
+            EXPECT_EQ(aiReturn_SUCCESS, material->Get(AI_MATKEY_CLEARCOAT_FACTOR, clearcoat_factor));
+            EXPECT_EQ(ai_real(1.0f), clearcoat_factor);
+
+            ai_real clearcoat_rough_factor(0.0f);
+            EXPECT_EQ(aiReturn_SUCCESS, material->Get(AI_MATKEY_CLEARCOAT_ROUGHNESS_FACTOR, clearcoat_rough_factor));
+            EXPECT_EQ(ai_real(0.03f), clearcoat_rough_factor);
+
+            // Should import the texture as diffuse and as base color
+            aiString path;
+            std::array<aiTextureMapMode, 2> modes;
+            static const std::array<aiTextureMapMode, 2> exp_modes = { aiTextureMapMode_Wrap, aiTextureMapMode_Wrap };
+            EXPECT_EQ(aiReturn_SUCCESS, material->GetTexture(AI_MATKEY_CLEARCOAT_TEXTURE, &path, nullptr, nullptr,
+                                                nullptr, nullptr, modes.data()));
+            EXPECT_STREQ(path.C_Str(), "PartialCoating.png");
+            EXPECT_EQ(exp_modes, modes);
+        }
+    }
+    EXPECT_TRUE(found_partial_coat);
+}
+
+TEST_F(utglTF2ImportExport, importglTF2_KHR_materials_clearcoat) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/glTF2/ClearCoat-glTF/ClearCoatTest.gltf", aiProcess_ValidateDataStructure);
+    VerifyClearCoatScene(scene);
+}
+
 #ifndef ASSIMP_BUILD_NO_EXPORT
 
+TEST_F(utglTF2ImportExport, importglTF2AndExport_KHR_materials_clearcoat) {
+    {
+        Assimp::Importer importer;
+        Assimp::Exporter exporter;
+        const aiScene* scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/glTF2/ClearCoat-glTF/ClearCoatTest.gltf", aiProcess_ValidateDataStructure);
+        ASSERT_NE(nullptr, scene);
+        // Export
+        EXPECT_EQ(aiReturn_SUCCESS, exporter.Export(scene, "glb2", ASSIMP_TEST_MODELS_DIR "/glTF2/ClearCoat-glTF/ClearCoatTest_out.glb"));
+    }
+
+    // And re-import
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/glTF2/ClearCoat-glTF/ClearCoatTest_out.glb", aiProcess_ValidateDataStructure);
+    VerifyClearCoatScene(scene);
+}
+
 TEST_F(utglTF2ImportExport, importglTF2AndExport_KHR_materials_pbrSpecularGlossiness) {
     Assimp::Importer importer;
     Assimp::Exporter exporter;