three 基础库
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( 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 */
class DRACOExporter {
parse( object, options = {
decodeSpeed: 5,
encodeSpeed: 5,
encoderMethod: DRACOExporter.MESH_EDGEBREAKER_ENCODING,
quantization: [ 16, 8, 8, 8, 8 ],
exportUvs: true,
exportNormals: true,
exportColor: false
} ) {
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_encoder to work.' );
}
const geometry = object.geometry;
const dracoEncoder = DracoEncoderModule();
const encoder = new dracoEncoder.Encoder();
let builder;
let 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();
const vertices = geometry.getAttribute( 'position' );
builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.POSITION, vertices.count, vertices.itemSize, vertices.array );
const faces = geometry.getIndex();
if ( faces !== null ) {
builder.AddFacesToMesh( dracoObject, faces.count / 3, faces.array );
} else {
const faces = new ( vertices.count > 65535 ? Uint32Array : Uint16Array )( vertices.count );
for ( let i = 0; i < faces.length; i ++ ) {
faces[ i ] = i;
}
builder.AddFacesToMesh( dracoObject, vertices.count, faces );
}
if ( options.exportNormals === true ) {
const normals = geometry.getAttribute( 'normal' );
if ( normals !== undefined ) {
builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.NORMAL, normals.count, normals.itemSize, normals.array );
}
}
if ( options.exportUvs === true ) {
const uvs = geometry.getAttribute( 'uv' );
if ( uvs !== undefined ) {
builder.AddFloatAttributeToMesh( dracoObject, dracoEncoder.TEX_COORD, uvs.count, uvs.itemSize, uvs.array );
}
}
if ( options.exportColor === true ) {
const 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();
const vertices = geometry.getAttribute( 'position' );
builder.AddFloatAttribute( dracoObject, dracoEncoder.POSITION, vertices.count, vertices.itemSize, vertices.array );
if ( options.exportColor === true ) {
const 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
const 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).
const encodeSpeed = options.encodeSpeed !== undefined ? options.encodeSpeed : 5;
const 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 ( let i = 0; i < 5; i ++ ) {
if ( options.quantization[ i ] !== undefined ) {
encoder.SetAttributeQuantization( i, options.quantization[ i ] );
}
}
}
let 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.
const outputData = new Int8Array( new ArrayBuffer( length ) );
for ( let 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;
} )();