Add support for KHR_materials_dispersion

ISSUES.md

@@ -42,6 +42,7 @@
 |INVALID_EXTENSION_NAME_FORMAT|Extension name has invalid format.|Warning|
 |INVALID_GL_VALUE|Invalid value `%1` for GL type '`%2`'.|Error|
 |KHR_LIGHTS_PUNCTUAL_LIGHT_SPOT_ANGLES|outerConeAngle (`%2`) is less than or equal to innerConeAngle (`%1`).|Error|
+|KHR_MATERIALS_DISPERSION_NO_VOLUME|The dispersion extension needs to be combined with the volume extension.|Warning|
 |KHR_MATERIALS_EMISSIVE_STRENGTH_ZERO_FACTOR|Emissive strength has no effect when the emissive factor is zero or undefined.|Warning|
 |KHR_MATERIALS_IRIDESCENCE_THICKNESS_RANGE_INVALID|Thickness maximum must be greater than or equal to the thickness minimum.|Error|
 |KHR_MATERIALS_IRIDESCENCE_THICKNESS_RANGE_WITHOUT_TEXTURE|Thickness minimum has no effect when a thickness texture is not defined.|Information|

README.md

@@ -37,6 +37,7 @@ NuGet package [Third-party contribution]: https://www.nuget.org/packages/GltfVal
   - EXT_texture_webp
   - KHR_lights_punctual
   - KHR_materials_clearcoat
+  - KHR_materials_dispersion
   - KHR_materials_emissive_strength
   - KHR_materials_ior
   - KHR_materials_iridescence
@@ -116,6 +117,10 @@ To publish an npm package, follow these steps after installation:
 1. Run `dart run grinder npm-publish`.
 2. `gltf-validator` npm package will be built to `build/node` and published to npm registry using `npm publish`.
 
+### Post-Build Steps
+1. To auto-format all source files, from the root folder run: `dart format --fix .`
+2. To run the tests, use: `dart test`
+
 ### Validation Issues List
 To generate [ISSUES.md](ISSUES.md), follow these steps after installation:
 1. Run `dart run grinder issues`.

lib/src/errors.dart

@@ -489,6 +489,12 @@ class SemanticError extends IssueType {
       (args) => 'outerConeAngle (${args[1]}) is less than or equal to '
           'innerConeAngle (${args[0]}).');
 
+  static final SemanticError khrMaterialsDispersionNoVolume = SemanticError._(
+      'KHR_MATERIALS_DISPERSION_NO_VOLUME',
+      (args) => 'The dispersion extension needs to be combined with '
+          'the volume extension.',
+      Severity.Warning);
+
   static final SemanticError khrMaterialsEmissiveStrengthZeroFactor =
       SemanticError._(
           'KHR_MATERIALS_EMISSIVE_STRENGTH_ZERO_FACTOR',

lib/src/ext/KHR_materials_dispersion/khr_materials_dispersion.dart

@@ -0,0 +1,62 @@
+// Copyright 2024 The Khronos Group Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+library gltf.extensions.khr_materials_dispersion;
+
+import 'package:gltf/src/base/gltf_property.dart';
+import 'package:gltf/src/ext/extensions.dart';
+
+const String KHR_MATERIALS_DISPERSION = 'KHR_materials_dispersion';
+
+const String DISPERSION = 'dispersion';
+
+const List<String> KHR_MATERIALS_DISPERSION_MEMBERS = <String>[
+  DISPERSION,
+];
+
+class KhrMaterialsDispersion extends GltfProperty {
+  final double dispersion;
+
+  KhrMaterialsDispersion._(
+      this.dispersion, Map<String, Object> extensions, Object extras)
+      : super(extensions, extras);
+
+  static KhrMaterialsDispersion fromMap(
+      Map<String, Object> map, Context context) {
+    if (context.validate) {
+      checkMembers(map, KHR_MATERIALS_DISPERSION_MEMBERS, context);
+    }
+
+    final dispersion = getFloat(map, DISPERSION, context, min: 0, def: 0);
+
+    final extensions = getExtensions(map, KhrMaterialsDispersion, context);
+
+    return KhrMaterialsDispersion._(
+        dispersion, extensions, getExtras(map, context));
+  }
+
+  @override
+  void link(Gltf gltf, Context context) {
+    if (!context.validate) {
+      return;
+    }
+
+    Object o = this;
+    while (o != null) {
+      o = context.owners[o];
+      if (o is Material) {
+        // The dispersion extension needs to be combined with KHR_materials_volume.
+        if (!o.extensions.containsKey(KHR_MATERIALS_VOLUME)) {
+          context.addIssue(SemanticError.khrMaterialsDispersionNoVolume);
+        }
+        break;
+      }
+    }
+  }
+}
+
+const Extension khrMaterialsDispersionExtension = Extension(
+    KHR_MATERIALS_DISPERSION, <Type, ExtensionDescriptor>{
+  Material: ExtensionDescriptor(KhrMaterialsDispersion.fromMap)
+});

lib/src/ext/extensions.dart

@@ -20,6 +20,7 @@ import 'package:gltf/src/base/gltf_property.dart';
 import 'package:gltf/src/ext/EXT_texture_webp/ext_texture_webp.dart';
 import 'package:gltf/src/ext/KHR_lights_punctual/khr_lights_punctual.dart';
 import 'package:gltf/src/ext/KHR_materials_clearcoat/khr_materials_clearcoat.dart';
+import 'package:gltf/src/ext/KHR_materials_dispersion/khr_materials_dispersion.dart';
 import 'package:gltf/src/ext/KHR_materials_emissive_strength/khr_materials_emissive_strength.dart';
 import 'package:gltf/src/ext/KHR_materials_ior/khr_materials_ior.dart';
 import 'package:gltf/src/ext/KHR_materials_iridescence/khr_materials_iridescence.dart';
@@ -38,6 +39,7 @@ import 'package:meta/meta.dart';
 export 'package:gltf/src/ext/EXT_texture_webp/ext_texture_webp.dart';
 export 'package:gltf/src/ext/KHR_lights_punctual/khr_lights_punctual.dart';
 export 'package:gltf/src/ext/KHR_materials_clearcoat/khr_materials_clearcoat.dart';
+export 'package:gltf/src/ext/KHR_materials_dispersion/khr_materials_dispersion.dart';
 export 'package:gltf/src/ext/KHR_materials_emissive_strength/khr_materials_emissive_strength.dart';
 export 'package:gltf/src/ext/KHR_materials_ior/khr_materials_ior.dart';
 export 'package:gltf/src/ext/KHR_materials_iridescence/khr_materials_iridescence.dart';
@@ -100,6 +102,7 @@ const List<Extension> kDefaultExtensions = <Extension>[
   extTextureWebPExtension,
   khrLightsPunctualExtension,
   khrMaterialsClearcoatExtension,
+  khrMaterialsDispersionExtension,
   khrMaterialsEmissiveStrengthExtension,
   khrMaterialsIorExtension,
   khrMaterialsIridescenceExtension,

test/ext/KHR_materials_dispersion/assets.json

@@ -0,0 +1,12 @@
+{
+    "material": {
+        "name": "material.KHR_materials_dispersion",
+        "tests": {
+            "custom_property.gltf": "Custom property",
+            "no_volume.gltf": "No volume extension",
+            "out_of_range.gltf": "Out of range values",
+            "unexpected_extension.gltf": "Unexpected extension object location",
+            "valid.gltf": "Valid"
+        }
+    }
+}

test/ext/KHR_materials_dispersion/data/material/custom_property.gltf

@@ -0,0 +1,23 @@
+{
+    "asset": {
+        "version": "2.0"
+    },
+    "extensionsUsed": [
+        "KHR_materials_dispersion",
+        "KHR_materials_volume",
+        "KHR_materials_transmission"
+    ],
+    "materials": [
+        {
+            "extensions": {
+                "KHR_materials_dispersion": {
+                    "customProperty": true
+                },
+                "KHR_materials_volume": {
+                    "thicknessFactor": 1
+                },
+                "KHR_materials_transmission": {}
+            }
+        }
+    ]
+}

test/ext/KHR_materials_dispersion/data/material/custom_property.gltf.report.json

@@ -0,0 +1,46 @@
+{
+    "uri": "test/ext/KHR_materials_dispersion/data/material/custom_property.gltf",
+    "mimeType": "model/gltf+json",
+    "validatorVersion": "2.0.0-dev.3.9",
+    "issues": {
+        "numErrors": 0,
+        "numWarnings": 1,
+        "numInfos": 1,
+        "numHints": 0,
+        "messages": [
+            {
+                "code": "UNEXPECTED_PROPERTY",
+                "message": "Unexpected property.",
+                "severity": 1,
+                "pointer": "/materials/0/extensions/KHR_materials_dispersion/customProperty"
+            },
+            {
+                "code": "UNUSED_OBJECT",
+                "message": "This object may be unused.",
+                "severity": 2,
+                "pointer": "/materials/0"
+            }
+        ],
+        "truncated": false
+    },
+    "info": {
+        "version": "2.0",
+        "extensionsUsed": [
+            "KHR_materials_dispersion",
+            "KHR_materials_volume",
+            "KHR_materials_transmission"
+        ],
+        "animationCount": 0,
+        "materialCount": 1,
+        "hasMorphTargets": false,
+        "hasSkins": false,
+        "hasTextures": false,
+        "hasDefaultScene": false,
+        "drawCallCount": 0,
+        "totalVertexCount": 0,
+        "totalTriangleCount": 0,
+        "maxUVs": 0,
+        "maxInfluences": 0,
+        "maxAttributes": 0
+    }
+}

test/ext/KHR_materials_dispersion/data/material/no_volume.gltf

@@ -0,0 +1,17 @@
+{
+    "asset": {
+        "version": "2.0"
+    },
+    "extensionsUsed": [
+        "KHR_materials_dispersion"
+    ],
+    "materials": [
+        {
+            "extensions": {
+                "KHR_materials_dispersion": {
+                    "dispersion": 1.0
+                }
+            }
+        }
+    ]
+}

test/ext/KHR_materials_dispersion/data/material/no_volume.gltf.report.json

@@ -0,0 +1,44 @@
+{
+    "uri": "test/ext/KHR_materials_dispersion/data/material/no_volume.gltf",
+    "mimeType": "model/gltf+json",
+    "validatorVersion": "2.0.0-dev.3.9",
+    "issues": {
+        "numErrors": 0,
+        "numWarnings": 1,
+        "numInfos": 1,
+        "numHints": 0,
+        "messages": [
+            {
+                "code": "KHR_MATERIALS_DISPERSION_NO_VOLUME",
+                "message": "The dispersion extension needs to be combined with the volume extension.",
+                "severity": 1,
+                "pointer": "/materials/0/extensions/KHR_materials_dispersion"
+            },
+            {
+                "code": "UNUSED_OBJECT",
+                "message": "This object may be unused.",
+                "severity": 2,
+                "pointer": "/materials/0"
+            }
+        ],
+        "truncated": false
+    },
+    "info": {
+        "version": "2.0",
+        "extensionsUsed": [
+            "KHR_materials_dispersion"
+        ],
+        "animationCount": 0,
+        "materialCount": 1,
+        "hasMorphTargets": false,
+        "hasSkins": false,
+        "hasTextures": false,
+        "hasDefaultScene": false,
+        "drawCallCount": 0,
+        "totalVertexCount": 0,
+        "totalTriangleCount": 0,
+        "maxUVs": 0,
+        "maxInfluences": 0,
+        "maxAttributes": 0
+    }
+}

test/ext/KHR_materials_dispersion/data/material/out_of_range.gltf

@@ -0,0 +1,23 @@
+{
+    "asset": {
+        "version": "2.0"
+    },
+    "extensionsUsed": [
+        "KHR_materials_dispersion",
+        "KHR_materials_volume",
+        "KHR_materials_transmission"
+    ],
+    "materials": [
+        {
+            "extensions": {
+                "KHR_materials_dispersion": {
+                    "dispersion": -0.5
+                },
+                "KHR_materials_volume": {
+                    "thicknessFactor": 1
+                },
+                "KHR_materials_transmission": {}
+            }
+        }
+    ]
+}

test/ext/KHR_materials_dispersion/data/material/out_of_range.gltf.report.json

@@ -0,0 +1,46 @@
+{
+    "uri": "test/ext/KHR_materials_dispersion/data/material/out_of_range.gltf",
+    "mimeType": "model/gltf+json",
+    "validatorVersion": "2.0.0-dev.3.9",
+    "issues": {
+        "numErrors": 1,
+        "numWarnings": 0,
+        "numInfos": 1,
+        "numHints": 0,
+        "messages": [
+            {
+                "code": "VALUE_NOT_IN_RANGE",
+                "message": "Value -0.5 is out of range.",
+                "severity": 0,
+                "pointer": "/materials/0/extensions/KHR_materials_dispersion/dispersion"
+            },
+            {
+                "code": "UNUSED_OBJECT",
+                "message": "This object may be unused.",
+                "severity": 2,
+                "pointer": "/materials/0"
+            }
+        ],
+        "truncated": false
+    },
+    "info": {
+        "version": "2.0",
+        "extensionsUsed": [
+            "KHR_materials_dispersion",
+            "KHR_materials_volume",
+            "KHR_materials_transmission"
+        ],
+        "animationCount": 0,
+        "materialCount": 1,
+        "hasMorphTargets": false,
+        "hasSkins": false,
+        "hasTextures": false,
+        "hasDefaultScene": false,
+        "drawCallCount": 0,
+        "totalVertexCount": 0,
+        "totalTriangleCount": 0,
+        "maxUVs": 0,
+        "maxInfluences": 0,
+        "maxAttributes": 0
+    }
+}

test/ext/KHR_materials_dispersion/data/material/unexpected_extension.gltf

@@ -0,0 +1,18 @@
+{
+    "asset": {
+        "version": "2.0"
+    },
+    "extensionsUsed": [
+        "KHR_materials_dispersion"
+    ],
+    "materials": [
+        {
+            "pbrMetallicRoughness": {
+                "extensions": {
+                    "KHR_materials_dispersion": {
+                    }
+                }
+            }
+        }
+    ]
+}