Implement support for KHR_mesh_quantization

This change implements support for KHR_mesh_quantization by simply
recognizing the extension as supported. It seems that the extension
works otherwise after various quantization fixes submitted previously
(with the most recent fix including correct morph target handling for
deltas that are quantized with a different data type vs baseline
attribute).

examples/js/loaders/GLTFLoader.js

@@ -188,6 +188,10 @@ THREE.GLTFLoader = ( function () {
 							extensions[ extensionName ] = new GLTFTextureTransformExtension();
 							break;
 
+						case EXTENSIONS.KHR_MESH_QUANTIZATION:
+							extensions[ extensionName ] = new GLTFMeshQuantizationExtension();
+							break;
+
 						default:
 
 							if ( extensionsRequired.indexOf( extensionName ) >= 0 ) {
@@ -263,6 +267,7 @@ THREE.GLTFLoader = ( function () {
 		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
 		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
 		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
+		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
 		MSFT_TEXTURE_DDS: 'MSFT_texture_dds'
 	};
 
@@ -981,6 +986,17 @@ THREE.GLTFLoader = ( function () {
 
 	}
 
+	/**
+	 * Mesh Quantization Extension
+	 *
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
+	 */
+	function GLTFMeshQuantizationExtension() {
+
+		this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;
+
+	}
+
 	/*********************************/
 	/********** INTERPOLATION ********/
 	/*********************************/

examples/jsm/loaders/GLTFLoader.js

@@ -252,6 +252,10 @@ var GLTFLoader = ( function () {
 							extensions[ extensionName ] = new GLTFTextureTransformExtension();
 							break;
 
+						case EXTENSIONS.KHR_MESH_QUANTIZATION:
+							extensions[ extensionName ] = new GLTFMeshQuantizationExtension();
+							break;
+
 						default:
 
 							if ( extensionsRequired.indexOf( extensionName ) >= 0 ) {
@@ -327,6 +331,7 @@ var GLTFLoader = ( function () {
 		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
 		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
 		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
+		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
 		MSFT_TEXTURE_DDS: 'MSFT_texture_dds'
 	};
 
@@ -1045,6 +1050,17 @@ var GLTFLoader = ( function () {
 
 	}
 
+	/**
+	 * Mesh Quantization Extension
+	 *
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
+	 */
+	function GLTFMeshQuantizationExtension() {
+
+		this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;
+
+	}
+
 	/*********************************/
 	/********** INTERPOLATION ********/
 	/*********************************/