Implement glTF extension KHR_materials_anisotropy

CHANGES.md

@@ -7,13 +7,15 @@
 ###### Additions :tada:
 
 - Added support for glTF models with the [KHR_materials_specular extension](https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_specular). [#11970](https://github.com/CesiumGS/cesium/pull/11970)
+- Added support for glTF models with the [KHR_materials_anisotropy extension](https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md). [#11988](https://github.com/CesiumGS/cesium/pull/11988)
 
 #### Fixes :wrench:
 
 - Fixed a bug where `scene.pickPosition` returned incorrect results against the globe when `depthTestAgainstTerrain` is `false`. [#4368](https://github.com/CesiumGS/cesium/issues/4368)
 - Fixed a bug where `TaskProcessor` worker loading would check the worker module ID rather than the absolute URL when determining if it is cross-origin. [#11833](https://github.com/CesiumGS/cesium/pull/11833)
 - Fixed a bug where cross-origin workers would error when loaded with the CommonJS `importScripts` shim instead of an ESM `import`. [#11833](https://github.com/CesiumGS/cesium/pull/11833)
 - Corrected the Typescript types for `Billboard.id` and `Label.id` to be `any` [#11973](https://github.com/CesiumGS/cesium/issues/11973)
+- Fixed a normalization error in image-based lighting [#11994](https://github.com/CesiumGS/cesium/issues/11994)
 
 ### 1.117 - 2024-05-01
 

Specs/Data/Models/glTF-2.0/BoxAnisotropy/README.md

@@ -0,0 +1,11 @@
+# Box Anisotropy
+
+## Screenshot
+
+![screenshot](screenshot/screenshot.png)
+
+## License Information
+
+Developed by Cesium for testing the KHR_materials_anisotropy extension. Please follow the [Cesium Trademark Terms and Conditions](https://github.com/AnalyticalGraphicsInc/cesium/wiki/CesiumTrademark.pdf).
+
+This model is licensed under a [Creative Commons Attribution 4.0 International License](http://creativecommons.org/licenses/by/4.0/).

Specs/Data/Models/glTF-2.0/BoxAnisotropy/glTF/BoxAnisotropy.gltf

@@ -0,0 +1,201 @@
+{
+    "asset": {
+        "generator": "COLLADA2GLTF",
+        "version": "2.0"
+    },
+    "scene": 0,
+    "scenes": [
+        {
+            "nodes": [
+                0
+            ]
+        }
+    ],
+    "nodes": [
+        {
+            "children": [
+                1
+            ],
+            "matrix": [
+                1.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                -1.0,
+                0.0,
+                0.0,
+                1.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                0.0,
+                1.0
+            ]
+        },
+        {
+            "mesh": 0
+        }
+    ],
+    "meshes": [
+        {
+            "primitives": [
+                {
+                    "attributes": {
+                        "NORMAL": 1,
+                        "POSITION": 2,
+                        "TEXCOORD_0": 3
+                    },
+                    "indices": 0,
+                    "mode": 4,
+                    "material": 0
+                }
+            ],
+            "name": "Mesh"
+        }
+    ],
+    "accessors": [
+        {
+            "bufferView": 0,
+            "byteOffset": 0,
+            "componentType": 5123,
+            "count": 36,
+            "max": [
+                23
+            ],
+            "min": [
+                0
+            ],
+            "type": "SCALAR"
+        },
+        {
+            "bufferView": 1,
+            "byteOffset": 0,
+            "componentType": 5126,
+            "count": 24,
+            "max": [
+                1.0,
+                1.0,
+                1.0
+            ],
+            "min": [
+                -1.0,
+                -1.0,
+                -1.0
+            ],
+            "type": "VEC3"
+        },
+        {
+            "bufferView": 1,
+            "byteOffset": 288,
+            "componentType": 5126,
+            "count": 24,
+            "max": [
+                0.5,
+                0.5,
+                0.5
+            ],
+            "min": [
+                -0.5,
+                -0.5,
+                -0.5
+            ],
+            "type": "VEC3"
+        },
+        {
+            "bufferView": 2,
+            "byteOffset": 0,
+            "componentType": 5126,
+            "count": 24,
+            "max": [
+                6.0,
+                1.0
+            ],
+            "min": [
+                0.0,
+                0.0
+            ],
+            "type": "VEC2"
+        }
+    ],
+    "materials": [
+        {
+            "pbrMetallicRoughness": {
+                "baseColorTexture": {
+                    "index": 0
+                },
+                "metallicFactor": 0.0
+            },
+            "normalTexture": {
+                "index": 0
+            },
+            "name": "Texture",
+            "extensions": {
+                "KHR_materials_anisotropy": {
+                    "anisotropyStrength": 0.5,
+                    "anisotropyRotation": 0.349065850398866,
+                    "anisotropyTexture": {
+                        "index": 0
+                    }
+                }
+            }
+        }
+    ],
+    "textures": [
+        {
+            "sampler": 0,
+            "source": 0
+        }
+    ],
+    "images": [
+        {
+            "uri": "CesiumLogoFlat.png"
+        }
+    ],
+    "samplers": [
+        {
+            "magFilter": 9729,
+            "minFilter": 9986,
+            "wrapS": 10497,
+            "wrapT": 10497
+        }
+    ],
+    "bufferViews": [
+        {
+            "buffer": 0,
+            "byteOffset": 768,
+            "byteLength": 72,
+            "target": 34963
+        },
+        {
+            "buffer": 0,
+            "byteOffset": 0,
+            "byteLength": 576,
+            "byteStride": 12,
+            "target": 34962
+        },
+        {
+            "buffer": 0,
+            "byteOffset": 576,
+            "byteLength": 192,
+            "byteStride": 8,
+            "target": 34962
+        }
+    ],
+    "buffers": [
+        {
+            "byteLength": 840,
+            "uri": "BoxAnisotropy.bin"
+        }
+    ],
+    "extensionsRequired": [
+      "KHR_draco_mesh_compression",
+      "KHR_materials_anisotropy"
+    ],
+    "extensionsUsed": [
+      "KHR_draco_mesh_compression",
+      "KHR_materials_anisotropy"
+    ]
+}

packages/engine/Source/Scene/GltfLoader.js

@@ -54,6 +54,7 @@ const {
   MetallicRoughness,
   SpecularGlossiness,
   Specular,
+  Anisotropy,
   Material,
 } = ModelComponents;
 
@@ -1565,6 +1566,27 @@ function loadSpecular(loader, specularInfo, frameState) {
   return specular;
 }
 
+function loadAnisotropy(loader, anisotropyInfo, frameState) {
+  const {
+    anisotropyStrength = Anisotropy.DEFAULT_ANISOTROPY_STRENGTH,
+    anisotropyRotation = Anisotropy.DEFAULT_ANISOTROPY_ROTATION,
+    anisotropyTexture,
+  } = anisotropyInfo;
+
+  const anisotropy = new Anisotropy();
+  if (defined(anisotropyTexture)) {
+    anisotropy.anisotropyTexture = loadTexture(
+      loader,
+      anisotropyTexture,
+      frameState
+    );
+  }
+  anisotropy.anisotropyStrength = anisotropyStrength;
+  anisotropy.anisotropyRotation = anisotropyRotation;
+
+  return anisotropy;
+}
+
 /**
  * Load textures and parse factors and flags for a glTF material
  *
@@ -1583,6 +1605,7 @@ function loadMaterial(loader, gltfMaterial, frameState) {
   );
   const pbrSpecularGlossiness = extensions.KHR_materials_pbrSpecularGlossiness;
   const pbrSpecular = extensions.KHR_materials_specular;
+  const pbrAnisotropy = extensions.KHR_materials_anisotropy;
   const pbrMetallicRoughness = gltfMaterial.pbrMetallicRoughness;
 
   material.unlit = defined(extensions.KHR_materials_unlit);
@@ -1601,9 +1624,12 @@ function loadMaterial(loader, gltfMaterial, frameState) {
         frameState
       );
     }
-    if (defined(pbrSpecular)) {
+    if (defined(pbrSpecular) && !material.unlit) {
       material.specular = loadSpecular(loader, pbrSpecular, frameState);
     }
+    if (defined(pbrAnisotropy) && !material.unlit) {
+      material.anisotropy = loadAnisotropy(loader, pbrAnisotropy, frameState);
+    }
   }
 
   // Top level textures