200 lines
3.8 KiB
JavaScript
200 lines
3.8 KiB
JavaScript
import { Vector3 } from 'three';
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/**
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* Usage:
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* const exporter = new STLExporter();
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*
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* // second argument is a list of options
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* const data = exporter.parse( mesh, { binary: true } );
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*
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*/
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class STLExporter {
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parse( scene, options = {} ) {
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options = Object.assign( {
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binary: false
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}, options );
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const binary = options.binary;
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//
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const objects = [];
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let triangles = 0;
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scene.traverse( function ( object ) {
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if ( object.isMesh ) {
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const geometry = object.geometry;
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const index = geometry.index;
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const positionAttribute = geometry.getAttribute( 'position' );
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triangles += ( index !== null ) ? ( index.count / 3 ) : ( positionAttribute.count / 3 );
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objects.push( {
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object3d: object,
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geometry: geometry
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} );
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}
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} );
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let output;
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let offset = 80; // skip header
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if ( binary === true ) {
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const bufferLength = triangles * 2 + triangles * 3 * 4 * 4 + 80 + 4;
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const arrayBuffer = new ArrayBuffer( bufferLength );
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output = new DataView( arrayBuffer );
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output.setUint32( offset, triangles, true ); offset += 4;
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} else {
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output = '';
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output += 'solid exported\n';
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}
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const vA = new Vector3();
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const vB = new Vector3();
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const vC = new Vector3();
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const cb = new Vector3();
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const ab = new Vector3();
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const normal = new Vector3();
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for ( let i = 0, il = objects.length; i < il; i ++ ) {
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const object = objects[ i ].object3d;
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const geometry = objects[ i ].geometry;
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const index = geometry.index;
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const positionAttribute = geometry.getAttribute( 'position' );
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if ( index !== null ) {
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// indexed geometry
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for ( let j = 0; j < index.count; j += 3 ) {
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const a = index.getX( j + 0 );
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const b = index.getX( j + 1 );
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const c = index.getX( j + 2 );
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writeFace( a, b, c, positionAttribute, object );
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}
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} else {
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// non-indexed geometry
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for ( let j = 0; j < positionAttribute.count; j += 3 ) {
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const a = j + 0;
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const b = j + 1;
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const c = j + 2;
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writeFace( a, b, c, positionAttribute, object );
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}
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}
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}
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if ( binary === false ) {
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output += 'endsolid exported\n';
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}
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return output;
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function writeFace( a, b, c, positionAttribute, object ) {
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vA.fromBufferAttribute( positionAttribute, a );
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vB.fromBufferAttribute( positionAttribute, b );
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vC.fromBufferAttribute( positionAttribute, c );
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if ( object.isSkinnedMesh === true ) {
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object.applyBoneTransform( a, vA );
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object.applyBoneTransform( b, vB );
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object.applyBoneTransform( c, vC );
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}
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vA.applyMatrix4( object.matrixWorld );
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vB.applyMatrix4( object.matrixWorld );
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vC.applyMatrix4( object.matrixWorld );
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writeNormal( vA, vB, vC );
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writeVertex( vA );
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writeVertex( vB );
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writeVertex( vC );
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if ( binary === true ) {
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output.setUint16( offset, 0, true ); offset += 2;
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} else {
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output += '\t\tendloop\n';
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output += '\tendfacet\n';
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}
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}
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function writeNormal( vA, vB, vC ) {
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cb.subVectors( vC, vB );
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ab.subVectors( vA, vB );
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cb.cross( ab ).normalize();
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normal.copy( cb ).normalize();
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if ( binary === true ) {
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output.setFloat32( offset, normal.x, true ); offset += 4;
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output.setFloat32( offset, normal.y, true ); offset += 4;
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output.setFloat32( offset, normal.z, true ); offset += 4;
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} else {
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output += '\tfacet normal ' + normal.x + ' ' + normal.y + ' ' + normal.z + '\n';
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output += '\t\touter loop\n';
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}
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}
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function writeVertex( vertex ) {
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if ( binary === true ) {
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output.setFloat32( offset, vertex.x, true ); offset += 4;
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output.setFloat32( offset, vertex.y, true ); offset += 4;
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output.setFloat32( offset, vertex.z, true ); offset += 4;
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} else {
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output += '\t\t\tvertex ' + vertex.x + ' ' + vertex.y + ' ' + vertex.z + '\n';
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}
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}
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}
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}
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export { STLExporter };
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