three.js/examples/js/exporters/DRACOExporter.js

( function () {

	/**
 * Export draco compressed files from threejs geometry objects.
 *
 * Draco files are compressed and usually are smaller than conventional 3D file formats.
 *
 * The exporter receives a options object containing
 *	- decodeSpeed, indicates how to tune the encoder regarding decode speed (0 gives better speed but worst quality)
 *	- encodeSpeed, indicates how to tune the encoder parameters (0 gives better speed but worst quality)
 *	- encoderMethod
 *	- quantization, indicates the presision of each type of data stored in the draco file in the order (POSITION, NORMAL, COLOR, TEX_COORD, GENERIC)
 *	- exportUvs
 *	- exportNormals
 */

	/* global DracoEncoderModule */
	var DRACOExporter = function () {};

	DRACOExporter.prototype = {
		constructor: DRACOExporter,
		parse: function ( object, options ) {

			if ( object.isBufferGeometry === true ) {

				throw new Error( 'DRACOExporter: The first parameter of parse() is now an instance of Mesh or Points.' );

			}

			if ( DracoEncoderModule === undefined ) {

				throw new Error( 'THREE.DRACOExporter: required the draco_decoder to work.' );

			}

			if ( options === undefined ) {

				options = {
					decodeSpeed: 5,
					encodeSpeed: 5,
					encoderMethod: DRACOExporter.MESH_EDGEBREAKER_ENCODING,
					quantization: [ 16, 8, 8, 8, 8 ],
					exportUvs: true,
					exportNormals: true,
					exportColor: false
				};

			}

			var geometry = object.geometry;
			var dracoEncoder = DracoEncoderModule();
			var encoder = new dracoEncoder.Encoder();
			var builder;
			var dracoObject;

			if ( geometry.isBufferGeometry !== true ) {

				throw new Error( 'THREE.DRACOExporter.parse(geometry, options): geometry is not a THREE.BufferGeometry instance.' );

			}

			if ( object.isMesh === true ) {

				builder = new dracoEncoder.MeshBuilder();
				dracoObject = new dracoEncoder.Mesh();
				var vertices = geometry.getAttribute( 'position' );
				builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.POSITION, vertices.count, vertices.itemSize, vertices.array );
				var faces = geometry.getIndex();

				if ( faces !== null ) {

					builder.AddFacesToMesh( dracoObject, faces.count / 3, faces.array );

				} else {

					var faces = new ( vertices.count > 65535 ? Uint32Array : Uint16Array )( vertices.count );

					for ( var i = 0; i < faces.length; i ++ ) {

						faces[ i ] = i;

					}

					builder.AddFacesToMesh( dracoObject, vertices.count, faces );

				}

				if ( options.exportNormals === true ) {

					var normals = geometry.getAttribute( 'normal' );

					if ( normals !== undefined ) {

						builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.NORMAL, normals.count, normals.itemSize, normals.array );

					}

				}

				if ( options.exportUvs === true ) {

					var uvs = geometry.getAttribute( 'uv' );

					if ( uvs !== undefined ) {

						builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.TEX_COORD, uvs.count, uvs.itemSize, uvs.array );

					}

				}

				if ( options.exportColor === true ) {

					var colors = geometry.getAttribute( 'color' );

					if ( colors !== undefined ) {

						builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.COLOR, colors.count, colors.itemSize, colors.array );

					}

				}

			} else if ( object.isPoints === true ) {

				builder = new dracoEncoder.PointCloudBuilder();
				dracoObject = new dracoEncoder.PointCloud();
				var vertices = geometry.getAttribute( 'position' );
				builder.AddFloatAttribute( dracoObject, dracoEncoder.POSITION, vertices.count, vertices.itemSize, vertices.array );

				if ( options.exportColor === true ) {

					var colors = geometry.getAttribute( 'color' );

					if ( colors !== undefined ) {

						builder.AddFloatAttribute( dracoObject, dracoEncoder.COLOR, colors.count, colors.itemSize, colors.array );

					}

				}

			} else {

				throw new Error( 'DRACOExporter: Unsupported object type.' );

			} //Compress using draco encoder


			var encodedData = new dracoEncoder.DracoInt8Array(); //Sets the desired encoding and decoding speed for the given options from 0 (slowest speed, but the best compression) to 10 (fastest, but the worst compression).

			var encodeSpeed = options.encodeSpeed !== undefined ? options.encodeSpeed : 5;
			var decodeSpeed = options.decodeSpeed !== undefined ? options.decodeSpeed : 5;
			encoder.SetSpeedOptions( encodeSpeed, decodeSpeed ); // Sets the desired encoding method for a given geometry.

			if ( options.encoderMethod !== undefined ) {

				encoder.SetEncodingMethod( options.encoderMethod );

			} // Sets the quantization (number of bits used to represent) compression options for a named attribute.
			// The attribute values will be quantized in a box defined by the maximum extent of the attribute values.


			if ( options.quantization !== undefined ) {

				for ( var i = 0; i < 5; i ++ ) {

					if ( options.quantization[ i ] !== undefined ) {

						encoder.SetAttributeQuantization( i, options.quantization[ i ] );

					}

				}

			}

			var length;

			if ( object.isMesh === true ) {

				length = encoder.EncodeMeshToDracoBuffer( dracoObject, encodedData );

			} else {

				length = encoder.EncodePointCloudToDracoBuffer( dracoObject, true, encodedData );

			}

			dracoEncoder.destroy( dracoObject );

			if ( length === 0 ) {

				throw new Error( 'THREE.DRACOExporter: Draco encoding failed.' );

			} //Copy encoded data to buffer.


			var outputData = new Int8Array( new ArrayBuffer( length ) );

			for ( var i = 0; i < length; i ++ ) {

				outputData[ i ] = encodedData.GetValue( i );

			}

			dracoEncoder.destroy( encodedData );
			dracoEncoder.destroy( encoder );
			dracoEncoder.destroy( builder );
			return outputData;

		}
	}; // Encoder methods

	DRACOExporter.MESH_EDGEBREAKER_ENCODING = 1;
	DRACOExporter.MESH_SEQUENTIAL_ENCODING = 0; // Geometry type

	DRACOExporter.POINT_CLOUD = 0;
	DRACOExporter.TRIANGULAR_MESH = 1; // Attribute type

	DRACOExporter.INVALID = - 1;
	DRACOExporter.POSITION = 0;
	DRACOExporter.NORMAL = 1;
	DRACOExporter.COLOR = 2;
	DRACOExporter.TEX_COORD = 3;
	DRACOExporter.GENERIC = 4;

	THREE.DRACOExporter = DRACOExporter;

} )();