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📄 STLLoader.js

📊 Analysis Summary

Metric Count
🔧 Functions 8
🧱 Classes 1
📦 Imports 8
📊 Variables & Constants 49

📚 Table of Contents

🛠️ File Location:

📂 examples/jsm/loaders/STLLoader.js

📦 Imports

Name Source
BufferAttribute three
BufferGeometry three
Color three
FileLoader three
Float32BufferAttribute three
Loader three
Vector3 three
SRGBColorSpace three

Variables & Constants

Name Type Kind Value Exported
scope this let/var this
loader any let/var new FileLoader( this.manager )
reader DataView<any> let/var new DataView( data )
face_size number let/var ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 )
expect number let/var 80 + ( 32 / 8 ) + ( n_faces * face_size )
solid number[] let/var [ 115, 111, 108, 105, 100 ]
reader DataView<any> let/var new DataView( data )
r any let/var *not shown*
g any let/var *not shown*
b any let/var *not shown*
hasColors boolean let/var false
colors any let/var *not shown*
defaultR any let/var *not shown*
defaultG any let/var *not shown*
defaultB any let/var *not shown*
alpha any let/var *not shown*
dataOffset 84 let/var 84
faceLength number let/var 12 * 4 + 2
geometry any let/var new BufferGeometry()
vertices Float32Array<ArrayBuffer> let/var new Float32Array( faces * 3 * 3 )
normals Float32Array<ArrayBuffer> let/var new Float32Array( faces * 3 * 3 )
color any let/var new Color()
start number let/var dataOffset + face * faceLength
vertexstart number let/var start + i * 12
componentIdx number let/var ( face * 3 * 3 ) + ( ( i - 1 ) * 3 )
geometry any let/var new BufferGeometry()
patternSolid RegExp let/var /solid([\s\S]*?)endsolid/g
patternFace RegExp let/var /facet([\s\S]*?)endfacet/g
patternName RegExp let/var /solid\s(.+)/
faceCounter number let/var 0
patternFloat string let/var /[\s]+([+-]?(?:\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?)/.source
patternVertex RegExp let/var new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' )
patternNormal RegExp let/var new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' )
vertices any[] let/var []
normals any[] let/var []
groupNames any[] let/var []
normal any let/var new Vector3()
result any let/var *not shown*
groupCount number let/var 0
startVertex number let/var 0
endVertex number let/var 0
solid string let/var result[ 0 ]
name string let/var ( result = patternName.exec( solid ) ) !== null ? result[ 1 ] : ''
vertexCountPerFace number let/var 0
normalCountPerFace number let/var 0
text string let/var result[ 0 ]
start number let/var startVertex
count number let/var endVertex - startVertex
array_buffer Uint8Array<ArrayBuffer> let/var new Uint8Array( buffer.length )

Functions

STLLoader.load(url: string, onLoad: (arg0: BufferGeometry) => any, onProgress: onProgressCallback, onError: onErrorCallback): void

JSDoc:

/**
     * Starts loading from the given URL and passes the loaded STL asset
     * to the `onLoad()` callback.
     *
     * @param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
     * @param {function(BufferGeometry)} onLoad - Executed when the loading process has been finished.
     * @param {onProgressCallback} onProgress - Executed while the loading is in progress.
     * @param {onErrorCallback} onError - Executed when errors occur.
     */

Parameters:

  • url string
  • onLoad (arg0: BufferGeometry) => any
  • onProgress onProgressCallback
  • onError onErrorCallback

Returns: void

Calls:

  • loader.setPath
  • loader.setResponseType
  • loader.setRequestHeader
  • loader.setWithCredentials
  • loader.load
  • onLoad
  • scope.parse
  • onError
  • console.error
  • scope.manager.itemError
Code
load( url, onLoad, onProgress, onError ) {

        const scope = this;

        const loader = new FileLoader( this.manager );
        loader.setPath( this.path );
        loader.setResponseType( 'arraybuffer' );
        loader.setRequestHeader( this.requestHeader );
        loader.setWithCredentials( this.withCredentials );

        loader.load( url, function ( text ) {

            try {

                onLoad( scope.parse( text ) );

            } catch ( e ) {

                if ( onError ) {

                    onError( e );

                } else {

                    console.error( e );

                }

                scope.manager.itemError( url );

            }

        }, onProgress, onError );

    }

STLLoader.parse(data: ArrayBuffer): BufferGeometry

JSDoc:

/**
     * Parses the given STL data and returns the resulting geometry.
     *
     * @param {ArrayBuffer} data - The raw STL data as an array buffer.
     * @return {BufferGeometry} The parsed geometry.
     */

Parameters:

  • data ArrayBuffer

Returns: BufferGeometry

Calls:

  • reader.getUint32
  • matchDataViewAt
  • reader.getUint8
  • reader.getFloat32
  • reader.getUint16
  • color.setRGB
  • geometry.setAttribute
  • patternSolid.exec
  • patternName.exec
  • groupNames.push
  • patternFace.exec
  • patternNormal.exec
  • parseFloat
  • patternVertex.exec
  • vertices.push
  • normals.push
  • console.error
  • geometry.addGroup
  • new TextDecoder().decode
  • buffer.charCodeAt
  • ensureBinary
  • isBinary
  • parseBinary
  • parseASCII
  • ensureString

Internal Comments:

// An ASCII STL data must begin with 'solid ' as the first six bytes. (x2)
// However, ASCII STLs lacking the SPACE after the 'd' are known to be (x2)
// plentiful.  So, check the first 5 bytes for 'solid'. (x2)
// Several encodings, such as UTF-8, precede the text with up to 5 bytes: (x2)
// https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding (x2)
// Search for "solid" to start anywhere after those prefixes. (x2)
// US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd' (x2)
// If "solid" text is matched to the current offset, declare it to be an ASCII STL.
// Couldn't find "solid" text at the beginning; it is binary STL.
// Check if each byte in query matches the corresponding byte from the current offset
// process STL header
// check for default color in header ("COLOR=rgba" sequence).
// facet has its own unique color (x3)
// every face have to own ONE valid normal
// each face have to own THREE valid vertices
// start (x2)

Code
parse( data ) {

        function isBinary( data ) {

            const reader = new DataView( data );
            const face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
            const n_faces = reader.getUint32( 80, true );
            const expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );

            if ( expect === reader.byteLength ) {

                return true;

            }

            // An ASCII STL data must begin with 'solid ' as the first six bytes.
            // However, ASCII STLs lacking the SPACE after the 'd' are known to be
            // plentiful.  So, check the first 5 bytes for 'solid'.

            // Several encodings, such as UTF-8, precede the text with up to 5 bytes:
            // https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding
            // Search for "solid" to start anywhere after those prefixes.

            // US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'

            const solid = [ 115, 111, 108, 105, 100 ];

            for ( let off = 0; off < 5; off ++ ) {

                // If "solid" text is matched to the current offset, declare it to be an ASCII STL.

                if ( matchDataViewAt( solid, reader, off ) ) return false;

            }

            // Couldn't find "solid" text at the beginning; it is binary STL.

            return true;

        }

        function matchDataViewAt( query, reader, offset ) {

            // Check if each byte in query matches the corresponding byte from the current offset

            for ( let i = 0, il = query.length; i < il; i ++ ) {

                if ( query[ i ] !== reader.getUint8( offset + i ) ) return false;

            }

            return true;

        }

        function parseBinary( data ) {

            const reader = new DataView( data );
            const faces = reader.getUint32( 80, true );

            let r, g, b, hasColors = false, colors;
            let defaultR, defaultG, defaultB, alpha;

            // process STL header
            // check for default color in header ("COLOR=rgba" sequence).

            for ( let index = 0; index < 80 - 10; index ++ ) {

                if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
                    ( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
                    ( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {

                    hasColors = true;
                    colors = new Float32Array( faces * 3 * 3 );

                    defaultR = reader.getUint8( index + 6 ) / 255;
                    defaultG = reader.getUint8( index + 7 ) / 255;
                    defaultB = reader.getUint8( index + 8 ) / 255;
                    alpha = reader.getUint8( index + 9 ) / 255;

                }

            }

            const dataOffset = 84;
            const faceLength = 12 * 4 + 2;

            const geometry = new BufferGeometry();

            const vertices = new Float32Array( faces * 3 * 3 );
            const normals = new Float32Array( faces * 3 * 3 );

            const color = new Color();

            for ( let face = 0; face < faces; face ++ ) {

                const start = dataOffset + face * faceLength;
                const normalX = reader.getFloat32( start, true );
                const normalY = reader.getFloat32( start + 4, true );
                const normalZ = reader.getFloat32( start + 8, true );

                if ( hasColors ) {

                    const packedColor = reader.getUint16( start + 48, true );

                    if ( ( packedColor & 0x8000 ) === 0 ) {

                        // facet has its own unique color

                        r = ( packedColor & 0x1F ) / 31;
                        g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
                        b = ( ( packedColor >> 10 ) & 0x1F ) / 31;

                    } else {

                        r = defaultR;
                        g = defaultG;
                        b = defaultB;

                    }

                }

                for ( let i = 1; i <= 3; i ++ ) {

                    const vertexstart = start + i * 12;
                    const componentIdx = ( face * 3 * 3 ) + ( ( i - 1 ) * 3 );

                    vertices[ componentIdx ] = reader.getFloat32( vertexstart, true );
                    vertices[ componentIdx + 1 ] = reader.getFloat32( vertexstart + 4, true );
                    vertices[ componentIdx + 2 ] = reader.getFloat32( vertexstart + 8, true );

                    normals[ componentIdx ] = normalX;
                    normals[ componentIdx + 1 ] = normalY;
                    normals[ componentIdx + 2 ] = normalZ;

                    if ( hasColors ) {

                        color.setRGB( r, g, b, SRGBColorSpace );

                        colors[ componentIdx ] = color.r;
                        colors[ componentIdx + 1 ] = color.g;
                        colors[ componentIdx + 2 ] = color.b;

                    }

                }

            }

            geometry.setAttribute( 'position', new BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new BufferAttribute( normals, 3 ) );

            if ( hasColors ) {

                geometry.setAttribute( 'color', new BufferAttribute( colors, 3 ) );
                geometry.hasColors = true;
                geometry.alpha = alpha;

            }

            return geometry;

        }

        function parseASCII( data ) {

            const geometry = new BufferGeometry();
            const patternSolid = /solid([\s\S]*?)endsolid/g;
            const patternFace = /facet([\s\S]*?)endfacet/g;
            const patternName = /solid\s(.+)/;
            let faceCounter = 0;

            const patternFloat = /[\s]+([+-]?(?:\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?)/.source;
            const patternVertex = new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' );
            const patternNormal = new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' );

            const vertices = [];
            const normals = [];
            const groupNames = [];

            const normal = new Vector3();

            let result;

            let groupCount = 0;
            let startVertex = 0;
            let endVertex = 0;

            while ( ( result = patternSolid.exec( data ) ) !== null ) {

                startVertex = endVertex;

                const solid = result[ 0 ];

                const name = ( result = patternName.exec( solid ) ) !== null ? result[ 1 ] : '';
                groupNames.push( name );

                while ( ( result = patternFace.exec( solid ) ) !== null ) {

                    let vertexCountPerFace = 0;
                    let normalCountPerFace = 0;

                    const text = result[ 0 ];

                    while ( ( result = patternNormal.exec( text ) ) !== null ) {

                        normal.x = parseFloat( result[ 1 ] );
                        normal.y = parseFloat( result[ 2 ] );
                        normal.z = parseFloat( result[ 3 ] );
                        normalCountPerFace ++;

                    }

                    while ( ( result = patternVertex.exec( text ) ) !== null ) {

                        vertices.push( parseFloat( result[ 1 ] ), parseFloat( result[ 2 ] ), parseFloat( result[ 3 ] ) );
                        normals.push( normal.x, normal.y, normal.z );
                        vertexCountPerFace ++;
                        endVertex ++;

                    }

                    // every face have to own ONE valid normal

                    if ( normalCountPerFace !== 1 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter );

                    }

                    // each face have to own THREE valid vertices

                    if ( vertexCountPerFace !== 3 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter );

                    }

                    faceCounter ++;

                }

                const start = startVertex;
                const count = endVertex - startVertex;

                geometry.userData.groupNames = groupNames;

                geometry.addGroup( start, count, groupCount );
                groupCount ++;

            }

            geometry.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );

            return geometry;

        }

        function ensureString( buffer ) {

            if ( typeof buffer !== 'string' ) {

                return new TextDecoder().decode( buffer );

            }

            return buffer;

        }

        function ensureBinary( buffer ) {

            if ( typeof buffer === 'string' ) {

                const array_buffer = new Uint8Array( buffer.length );
                for ( let i = 0; i < buffer.length; i ++ ) {

                    array_buffer[ i ] = buffer.charCodeAt( i ) & 0xff; // implicitly assumes little-endian

                }

                return array_buffer.buffer || array_buffer;

            } else {

                return buffer;

            }

        }

        // start

        const binData = ensureBinary( data );

        return isBinary( binData ) ? parseBinary( binData ) : parseASCII( ensureString( data ) );

    }

isBinary(data: any): boolean

Parameters:

  • data any

Returns: boolean

Calls:

  • reader.getUint32
  • matchDataViewAt

Internal Comments:

// An ASCII STL data must begin with 'solid ' as the first six bytes. (x2)
// However, ASCII STLs lacking the SPACE after the 'd' are known to be (x2)
// plentiful.  So, check the first 5 bytes for 'solid'. (x2)
// Several encodings, such as UTF-8, precede the text with up to 5 bytes: (x2)
// https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding (x2)
// Search for "solid" to start anywhere after those prefixes. (x2)
// US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd' (x2)
// If "solid" text is matched to the current offset, declare it to be an ASCII STL.
// Couldn't find "solid" text at the beginning; it is binary STL.

Code
function isBinary( data ) {

            const reader = new DataView( data );
            const face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
            const n_faces = reader.getUint32( 80, true );
            const expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );

            if ( expect === reader.byteLength ) {

                return true;

            }

            // An ASCII STL data must begin with 'solid ' as the first six bytes.
            // However, ASCII STLs lacking the SPACE after the 'd' are known to be
            // plentiful.  So, check the first 5 bytes for 'solid'.

            // Several encodings, such as UTF-8, precede the text with up to 5 bytes:
            // https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding
            // Search for "solid" to start anywhere after those prefixes.

            // US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'

            const solid = [ 115, 111, 108, 105, 100 ];

            for ( let off = 0; off < 5; off ++ ) {

                // If "solid" text is matched to the current offset, declare it to be an ASCII STL.

                if ( matchDataViewAt( solid, reader, off ) ) return false;

            }

            // Couldn't find "solid" text at the beginning; it is binary STL.

            return true;

        }

matchDataViewAt(query: any, reader: any, offset: any): boolean

Parameters:

  • query any
  • reader any
  • offset any

Returns: boolean

Calls:

  • reader.getUint8

Internal Comments:

// Check if each byte in query matches the corresponding byte from the current offset

Code
function matchDataViewAt( query, reader, offset ) {

            // Check if each byte in query matches the corresponding byte from the current offset

            for ( let i = 0, il = query.length; i < il; i ++ ) {

                if ( query[ i ] !== reader.getUint8( offset + i ) ) return false;

            }

            return true;

        }

parseBinary(data: any): any

Parameters:

  • data any

Returns: any

Calls:

  • reader.getUint32
  • reader.getUint8
  • reader.getFloat32
  • reader.getUint16
  • color.setRGB
  • geometry.setAttribute

Internal Comments:

// process STL header
// check for default color in header ("COLOR=rgba" sequence).
// facet has its own unique color (x3)

Code
function parseBinary( data ) {

            const reader = new DataView( data );
            const faces = reader.getUint32( 80, true );

            let r, g, b, hasColors = false, colors;
            let defaultR, defaultG, defaultB, alpha;

            // process STL header
            // check for default color in header ("COLOR=rgba" sequence).

            for ( let index = 0; index < 80 - 10; index ++ ) {

                if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
                    ( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
                    ( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {

                    hasColors = true;
                    colors = new Float32Array( faces * 3 * 3 );

                    defaultR = reader.getUint8( index + 6 ) / 255;
                    defaultG = reader.getUint8( index + 7 ) / 255;
                    defaultB = reader.getUint8( index + 8 ) / 255;
                    alpha = reader.getUint8( index + 9 ) / 255;

                }

            }

            const dataOffset = 84;
            const faceLength = 12 * 4 + 2;

            const geometry = new BufferGeometry();

            const vertices = new Float32Array( faces * 3 * 3 );
            const normals = new Float32Array( faces * 3 * 3 );

            const color = new Color();

            for ( let face = 0; face < faces; face ++ ) {

                const start = dataOffset + face * faceLength;
                const normalX = reader.getFloat32( start, true );
                const normalY = reader.getFloat32( start + 4, true );
                const normalZ = reader.getFloat32( start + 8, true );

                if ( hasColors ) {

                    const packedColor = reader.getUint16( start + 48, true );

                    if ( ( packedColor & 0x8000 ) === 0 ) {

                        // facet has its own unique color

                        r = ( packedColor & 0x1F ) / 31;
                        g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
                        b = ( ( packedColor >> 10 ) & 0x1F ) / 31;

                    } else {

                        r = defaultR;
                        g = defaultG;
                        b = defaultB;

                    }

                }

                for ( let i = 1; i <= 3; i ++ ) {

                    const vertexstart = start + i * 12;
                    const componentIdx = ( face * 3 * 3 ) + ( ( i - 1 ) * 3 );

                    vertices[ componentIdx ] = reader.getFloat32( vertexstart, true );
                    vertices[ componentIdx + 1 ] = reader.getFloat32( vertexstart + 4, true );
                    vertices[ componentIdx + 2 ] = reader.getFloat32( vertexstart + 8, true );

                    normals[ componentIdx ] = normalX;
                    normals[ componentIdx + 1 ] = normalY;
                    normals[ componentIdx + 2 ] = normalZ;

                    if ( hasColors ) {

                        color.setRGB( r, g, b, SRGBColorSpace );

                        colors[ componentIdx ] = color.r;
                        colors[ componentIdx + 1 ] = color.g;
                        colors[ componentIdx + 2 ] = color.b;

                    }

                }

            }

            geometry.setAttribute( 'position', new BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new BufferAttribute( normals, 3 ) );

            if ( hasColors ) {

                geometry.setAttribute( 'color', new BufferAttribute( colors, 3 ) );
                geometry.hasColors = true;
                geometry.alpha = alpha;

            }

            return geometry;

        }

parseASCII(data: any): any

Parameters:

  • data any

Returns: any

Calls:

  • patternSolid.exec
  • patternName.exec
  • groupNames.push
  • patternFace.exec
  • patternNormal.exec
  • parseFloat
  • patternVertex.exec
  • vertices.push
  • normals.push
  • console.error
  • geometry.addGroup
  • geometry.setAttribute

Internal Comments:

// every face have to own ONE valid normal
// each face have to own THREE valid vertices

Code
function parseASCII( data ) {

            const geometry = new BufferGeometry();
            const patternSolid = /solid([\s\S]*?)endsolid/g;
            const patternFace = /facet([\s\S]*?)endfacet/g;
            const patternName = /solid\s(.+)/;
            let faceCounter = 0;

            const patternFloat = /[\s]+([+-]?(?:\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?)/.source;
            const patternVertex = new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' );
            const patternNormal = new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' );

            const vertices = [];
            const normals = [];
            const groupNames = [];

            const normal = new Vector3();

            let result;

            let groupCount = 0;
            let startVertex = 0;
            let endVertex = 0;

            while ( ( result = patternSolid.exec( data ) ) !== null ) {

                startVertex = endVertex;

                const solid = result[ 0 ];

                const name = ( result = patternName.exec( solid ) ) !== null ? result[ 1 ] : '';
                groupNames.push( name );

                while ( ( result = patternFace.exec( solid ) ) !== null ) {

                    let vertexCountPerFace = 0;
                    let normalCountPerFace = 0;

                    const text = result[ 0 ];

                    while ( ( result = patternNormal.exec( text ) ) !== null ) {

                        normal.x = parseFloat( result[ 1 ] );
                        normal.y = parseFloat( result[ 2 ] );
                        normal.z = parseFloat( result[ 3 ] );
                        normalCountPerFace ++;

                    }

                    while ( ( result = patternVertex.exec( text ) ) !== null ) {

                        vertices.push( parseFloat( result[ 1 ] ), parseFloat( result[ 2 ] ), parseFloat( result[ 3 ] ) );
                        normals.push( normal.x, normal.y, normal.z );
                        vertexCountPerFace ++;
                        endVertex ++;

                    }

                    // every face have to own ONE valid normal

                    if ( normalCountPerFace !== 1 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter );

                    }

                    // each face have to own THREE valid vertices

                    if ( vertexCountPerFace !== 3 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter );

                    }

                    faceCounter ++;

                }

                const start = startVertex;
                const count = endVertex - startVertex;

                geometry.userData.groupNames = groupNames;

                geometry.addGroup( start, count, groupCount );
                groupCount ++;

            }

            geometry.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );

            return geometry;

        }

ensureString(buffer: any): string

Parameters:

  • buffer any

Returns: string

Calls:

  • new TextDecoder().decode
Code
function ensureString( buffer ) {

            if ( typeof buffer !== 'string' ) {

                return new TextDecoder().decode( buffer );

            }

            return buffer;

        }

ensureBinary(buffer: any): any

Parameters:

  • buffer any

Returns: any

Calls:

  • buffer.charCodeAt
Code
function ensureBinary( buffer ) {

            if ( typeof buffer === 'string' ) {

                const array_buffer = new Uint8Array( buffer.length );
                for ( let i = 0; i < buffer.length; i ++ ) {

                    array_buffer[ i ] = buffer.charCodeAt( i ) & 0xff; // implicitly assumes little-endian

                }

                return array_buffer.buffer || array_buffer;

            } else {

                return buffer;

            }

        }

Classes

STLLoader

Class Code
class STLLoader extends Loader {

    /**
     * Constructs a new STL loader.
     *
     * @param {LoadingManager} [manager] - The loading manager.
     */
    constructor( manager ) {

        super( manager );

    }

    /**
     * Starts loading from the given URL and passes the loaded STL asset
     * to the `onLoad()` callback.
     *
     * @param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
     * @param {function(BufferGeometry)} onLoad - Executed when the loading process has been finished.
     * @param {onProgressCallback} onProgress - Executed while the loading is in progress.
     * @param {onErrorCallback} onError - Executed when errors occur.
     */
    load( url, onLoad, onProgress, onError ) {

        const scope = this;

        const loader = new FileLoader( this.manager );
        loader.setPath( this.path );
        loader.setResponseType( 'arraybuffer' );
        loader.setRequestHeader( this.requestHeader );
        loader.setWithCredentials( this.withCredentials );

        loader.load( url, function ( text ) {

            try {

                onLoad( scope.parse( text ) );

            } catch ( e ) {

                if ( onError ) {

                    onError( e );

                } else {

                    console.error( e );

                }

                scope.manager.itemError( url );

            }

        }, onProgress, onError );

    }

    /**
     * Parses the given STL data and returns the resulting geometry.
     *
     * @param {ArrayBuffer} data - The raw STL data as an array buffer.
     * @return {BufferGeometry} The parsed geometry.
     */
    parse( data ) {

        function isBinary( data ) {

            const reader = new DataView( data );
            const face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
            const n_faces = reader.getUint32( 80, true );
            const expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );

            if ( expect === reader.byteLength ) {

                return true;

            }

            // An ASCII STL data must begin with 'solid ' as the first six bytes.
            // However, ASCII STLs lacking the SPACE after the 'd' are known to be
            // plentiful.  So, check the first 5 bytes for 'solid'.

            // Several encodings, such as UTF-8, precede the text with up to 5 bytes:
            // https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding
            // Search for "solid" to start anywhere after those prefixes.

            // US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'

            const solid = [ 115, 111, 108, 105, 100 ];

            for ( let off = 0; off < 5; off ++ ) {

                // If "solid" text is matched to the current offset, declare it to be an ASCII STL.

                if ( matchDataViewAt( solid, reader, off ) ) return false;

            }

            // Couldn't find "solid" text at the beginning; it is binary STL.

            return true;

        }

        function matchDataViewAt( query, reader, offset ) {

            // Check if each byte in query matches the corresponding byte from the current offset

            for ( let i = 0, il = query.length; i < il; i ++ ) {

                if ( query[ i ] !== reader.getUint8( offset + i ) ) return false;

            }

            return true;

        }

        function parseBinary( data ) {

            const reader = new DataView( data );
            const faces = reader.getUint32( 80, true );

            let r, g, b, hasColors = false, colors;
            let defaultR, defaultG, defaultB, alpha;

            // process STL header
            // check for default color in header ("COLOR=rgba" sequence).

            for ( let index = 0; index < 80 - 10; index ++ ) {

                if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
                    ( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
                    ( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {

                    hasColors = true;
                    colors = new Float32Array( faces * 3 * 3 );

                    defaultR = reader.getUint8( index + 6 ) / 255;
                    defaultG = reader.getUint8( index + 7 ) / 255;
                    defaultB = reader.getUint8( index + 8 ) / 255;
                    alpha = reader.getUint8( index + 9 ) / 255;

                }

            }

            const dataOffset = 84;
            const faceLength = 12 * 4 + 2;

            const geometry = new BufferGeometry();

            const vertices = new Float32Array( faces * 3 * 3 );
            const normals = new Float32Array( faces * 3 * 3 );

            const color = new Color();

            for ( let face = 0; face < faces; face ++ ) {

                const start = dataOffset + face * faceLength;
                const normalX = reader.getFloat32( start, true );
                const normalY = reader.getFloat32( start + 4, true );
                const normalZ = reader.getFloat32( start + 8, true );

                if ( hasColors ) {

                    const packedColor = reader.getUint16( start + 48, true );

                    if ( ( packedColor & 0x8000 ) === 0 ) {

                        // facet has its own unique color

                        r = ( packedColor & 0x1F ) / 31;
                        g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
                        b = ( ( packedColor >> 10 ) & 0x1F ) / 31;

                    } else {

                        r = defaultR;
                        g = defaultG;
                        b = defaultB;

                    }

                }

                for ( let i = 1; i <= 3; i ++ ) {

                    const vertexstart = start + i * 12;
                    const componentIdx = ( face * 3 * 3 ) + ( ( i - 1 ) * 3 );

                    vertices[ componentIdx ] = reader.getFloat32( vertexstart, true );
                    vertices[ componentIdx + 1 ] = reader.getFloat32( vertexstart + 4, true );
                    vertices[ componentIdx + 2 ] = reader.getFloat32( vertexstart + 8, true );

                    normals[ componentIdx ] = normalX;
                    normals[ componentIdx + 1 ] = normalY;
                    normals[ componentIdx + 2 ] = normalZ;

                    if ( hasColors ) {

                        color.setRGB( r, g, b, SRGBColorSpace );

                        colors[ componentIdx ] = color.r;
                        colors[ componentIdx + 1 ] = color.g;
                        colors[ componentIdx + 2 ] = color.b;

                    }

                }

            }

            geometry.setAttribute( 'position', new BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new BufferAttribute( normals, 3 ) );

            if ( hasColors ) {

                geometry.setAttribute( 'color', new BufferAttribute( colors, 3 ) );
                geometry.hasColors = true;
                geometry.alpha = alpha;

            }

            return geometry;

        }

        function parseASCII( data ) {

            const geometry = new BufferGeometry();
            const patternSolid = /solid([\s\S]*?)endsolid/g;
            const patternFace = /facet([\s\S]*?)endfacet/g;
            const patternName = /solid\s(.+)/;
            let faceCounter = 0;

            const patternFloat = /[\s]+([+-]?(?:\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?)/.source;
            const patternVertex = new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' );
            const patternNormal = new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' );

            const vertices = [];
            const normals = [];
            const groupNames = [];

            const normal = new Vector3();

            let result;

            let groupCount = 0;
            let startVertex = 0;
            let endVertex = 0;

            while ( ( result = patternSolid.exec( data ) ) !== null ) {

                startVertex = endVertex;

                const solid = result[ 0 ];

                const name = ( result = patternName.exec( solid ) ) !== null ? result[ 1 ] : '';
                groupNames.push( name );

                while ( ( result = patternFace.exec( solid ) ) !== null ) {

                    let vertexCountPerFace = 0;
                    let normalCountPerFace = 0;

                    const text = result[ 0 ];

                    while ( ( result = patternNormal.exec( text ) ) !== null ) {

                        normal.x = parseFloat( result[ 1 ] );
                        normal.y = parseFloat( result[ 2 ] );
                        normal.z = parseFloat( result[ 3 ] );
                        normalCountPerFace ++;

                    }

                    while ( ( result = patternVertex.exec( text ) ) !== null ) {

                        vertices.push( parseFloat( result[ 1 ] ), parseFloat( result[ 2 ] ), parseFloat( result[ 3 ] ) );
                        normals.push( normal.x, normal.y, normal.z );
                        vertexCountPerFace ++;
                        endVertex ++;

                    }

                    // every face have to own ONE valid normal

                    if ( normalCountPerFace !== 1 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter );

                    }

                    // each face have to own THREE valid vertices

                    if ( vertexCountPerFace !== 3 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter );

                    }

                    faceCounter ++;

                }

                const start = startVertex;
                const count = endVertex - startVertex;

                geometry.userData.groupNames = groupNames;

                geometry.addGroup( start, count, groupCount );
                groupCount ++;

            }

            geometry.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );

            return geometry;

        }

        function ensureString( buffer ) {

            if ( typeof buffer !== 'string' ) {

                return new TextDecoder().decode( buffer );

            }

            return buffer;

        }

        function ensureBinary( buffer ) {

            if ( typeof buffer === 'string' ) {

                const array_buffer = new Uint8Array( buffer.length );
                for ( let i = 0; i < buffer.length; i ++ ) {

                    array_buffer[ i ] = buffer.charCodeAt( i ) & 0xff; // implicitly assumes little-endian

                }

                return array_buffer.buffer || array_buffer;

            } else {

                return buffer;

            }

        }

        // start

        const binData = ensureBinary( data );

        return isBinary( binData ) ? parseBinary( binData ) : parseASCII( ensureString( data ) );

    }

}

Methods

load(url: string, onLoad: (arg0: BufferGeometry) => any, onProgress: onProgressCallback, onError: onErrorCallback): void
Code
load( url, onLoad, onProgress, onError ) {

        const scope = this;

        const loader = new FileLoader( this.manager );
        loader.setPath( this.path );
        loader.setResponseType( 'arraybuffer' );
        loader.setRequestHeader( this.requestHeader );
        loader.setWithCredentials( this.withCredentials );

        loader.load( url, function ( text ) {

            try {

                onLoad( scope.parse( text ) );

            } catch ( e ) {

                if ( onError ) {

                    onError( e );

                } else {

                    console.error( e );

                }

                scope.manager.itemError( url );

            }

        }, onProgress, onError );

    }
parse(data: ArrayBuffer): BufferGeometry
Code
parse( data ) {

        function isBinary( data ) {

            const reader = new DataView( data );
            const face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
            const n_faces = reader.getUint32( 80, true );
            const expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );

            if ( expect === reader.byteLength ) {

                return true;

            }

            // An ASCII STL data must begin with 'solid ' as the first six bytes.
            // However, ASCII STLs lacking the SPACE after the 'd' are known to be
            // plentiful.  So, check the first 5 bytes for 'solid'.

            // Several encodings, such as UTF-8, precede the text with up to 5 bytes:
            // https://en.wikipedia.org/wiki/Byte_order_mark#Byte_order_marks_by_encoding
            // Search for "solid" to start anywhere after those prefixes.

            // US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'

            const solid = [ 115, 111, 108, 105, 100 ];

            for ( let off = 0; off < 5; off ++ ) {

                // If "solid" text is matched to the current offset, declare it to be an ASCII STL.

                if ( matchDataViewAt( solid, reader, off ) ) return false;

            }

            // Couldn't find "solid" text at the beginning; it is binary STL.

            return true;

        }

        function matchDataViewAt( query, reader, offset ) {

            // Check if each byte in query matches the corresponding byte from the current offset

            for ( let i = 0, il = query.length; i < il; i ++ ) {

                if ( query[ i ] !== reader.getUint8( offset + i ) ) return false;

            }

            return true;

        }

        function parseBinary( data ) {

            const reader = new DataView( data );
            const faces = reader.getUint32( 80, true );

            let r, g, b, hasColors = false, colors;
            let defaultR, defaultG, defaultB, alpha;

            // process STL header
            // check for default color in header ("COLOR=rgba" sequence).

            for ( let index = 0; index < 80 - 10; index ++ ) {

                if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
                    ( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
                    ( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {

                    hasColors = true;
                    colors = new Float32Array( faces * 3 * 3 );

                    defaultR = reader.getUint8( index + 6 ) / 255;
                    defaultG = reader.getUint8( index + 7 ) / 255;
                    defaultB = reader.getUint8( index + 8 ) / 255;
                    alpha = reader.getUint8( index + 9 ) / 255;

                }

            }

            const dataOffset = 84;
            const faceLength = 12 * 4 + 2;

            const geometry = new BufferGeometry();

            const vertices = new Float32Array( faces * 3 * 3 );
            const normals = new Float32Array( faces * 3 * 3 );

            const color = new Color();

            for ( let face = 0; face < faces; face ++ ) {

                const start = dataOffset + face * faceLength;
                const normalX = reader.getFloat32( start, true );
                const normalY = reader.getFloat32( start + 4, true );
                const normalZ = reader.getFloat32( start + 8, true );

                if ( hasColors ) {

                    const packedColor = reader.getUint16( start + 48, true );

                    if ( ( packedColor & 0x8000 ) === 0 ) {

                        // facet has its own unique color

                        r = ( packedColor & 0x1F ) / 31;
                        g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
                        b = ( ( packedColor >> 10 ) & 0x1F ) / 31;

                    } else {

                        r = defaultR;
                        g = defaultG;
                        b = defaultB;

                    }

                }

                for ( let i = 1; i <= 3; i ++ ) {

                    const vertexstart = start + i * 12;
                    const componentIdx = ( face * 3 * 3 ) + ( ( i - 1 ) * 3 );

                    vertices[ componentIdx ] = reader.getFloat32( vertexstart, true );
                    vertices[ componentIdx + 1 ] = reader.getFloat32( vertexstart + 4, true );
                    vertices[ componentIdx + 2 ] = reader.getFloat32( vertexstart + 8, true );

                    normals[ componentIdx ] = normalX;
                    normals[ componentIdx + 1 ] = normalY;
                    normals[ componentIdx + 2 ] = normalZ;

                    if ( hasColors ) {

                        color.setRGB( r, g, b, SRGBColorSpace );

                        colors[ componentIdx ] = color.r;
                        colors[ componentIdx + 1 ] = color.g;
                        colors[ componentIdx + 2 ] = color.b;

                    }

                }

            }

            geometry.setAttribute( 'position', new BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new BufferAttribute( normals, 3 ) );

            if ( hasColors ) {

                geometry.setAttribute( 'color', new BufferAttribute( colors, 3 ) );
                geometry.hasColors = true;
                geometry.alpha = alpha;

            }

            return geometry;

        }

        function parseASCII( data ) {

            const geometry = new BufferGeometry();
            const patternSolid = /solid([\s\S]*?)endsolid/g;
            const patternFace = /facet([\s\S]*?)endfacet/g;
            const patternName = /solid\s(.+)/;
            let faceCounter = 0;

            const patternFloat = /[\s]+([+-]?(?:\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?)/.source;
            const patternVertex = new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' );
            const patternNormal = new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' );

            const vertices = [];
            const normals = [];
            const groupNames = [];

            const normal = new Vector3();

            let result;

            let groupCount = 0;
            let startVertex = 0;
            let endVertex = 0;

            while ( ( result = patternSolid.exec( data ) ) !== null ) {

                startVertex = endVertex;

                const solid = result[ 0 ];

                const name = ( result = patternName.exec( solid ) ) !== null ? result[ 1 ] : '';
                groupNames.push( name );

                while ( ( result = patternFace.exec( solid ) ) !== null ) {

                    let vertexCountPerFace = 0;
                    let normalCountPerFace = 0;

                    const text = result[ 0 ];

                    while ( ( result = patternNormal.exec( text ) ) !== null ) {

                        normal.x = parseFloat( result[ 1 ] );
                        normal.y = parseFloat( result[ 2 ] );
                        normal.z = parseFloat( result[ 3 ] );
                        normalCountPerFace ++;

                    }

                    while ( ( result = patternVertex.exec( text ) ) !== null ) {

                        vertices.push( parseFloat( result[ 1 ] ), parseFloat( result[ 2 ] ), parseFloat( result[ 3 ] ) );
                        normals.push( normal.x, normal.y, normal.z );
                        vertexCountPerFace ++;
                        endVertex ++;

                    }

                    // every face have to own ONE valid normal

                    if ( normalCountPerFace !== 1 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter );

                    }

                    // each face have to own THREE valid vertices

                    if ( vertexCountPerFace !== 3 ) {

                        console.error( 'THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter );

                    }

                    faceCounter ++;

                }

                const start = startVertex;
                const count = endVertex - startVertex;

                geometry.userData.groupNames = groupNames;

                geometry.addGroup( start, count, groupCount );
                groupCount ++;

            }

            geometry.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
            geometry.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );

            return geometry;

        }

        function ensureString( buffer ) {

            if ( typeof buffer !== 'string' ) {

                return new TextDecoder().decode( buffer );

            }

            return buffer;

        }

        function ensureBinary( buffer ) {

            if ( typeof buffer === 'string' ) {

                const array_buffer = new Uint8Array( buffer.length );
                for ( let i = 0; i < buffer.length; i ++ ) {

                    array_buffer[ i ] = buffer.charCodeAt( i ) & 0xff; // implicitly assumes little-endian

                }

                return array_buffer.buffer || array_buffer;

            } else {

                return buffer;

            }

        }

        // start

        const binData = ensureBinary( data );

        return isBinary( binData ) ? parseBinary( binData ) : parseASCII( ensureString( data ) );

    }