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Merge pull request #20535 from Mcgode/edge-split-modifier
Examples: Add EdgeSplitModifier
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‎examples/js/modifiers/EdgeSplitModifier.js‎

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console.warn( "THREE.EdgeSplitModifier: As part of the transition to ES6 Modules, the files in 'examples/js' were deprecated in May 2020 (r117) and will be deleted in December 2020 (r124). You can find more information about developing using ES6 Modules in https://threejs.org/docs/#manual/en/introduction/Installation." );
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THREE.EdgeSplitModifier = function () {
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const A = new THREE.Vector3();
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const B = new THREE.Vector3();
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const C = new THREE.Vector3();
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let positions, normals;
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let indexes;
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let pointToIndexMap, splitIndexes;
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function computeNormals() {
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normals = new Float32Array( indexes.length * 3 );
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for ( let i = 0; i < indexes.length; i += 3 ) {
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let index = indexes[ i ];
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A.set(
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positions[ 3 * index ],
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positions[ 3 * index + 1 ],
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positions[ 3 * index + 2 ] );
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index = indexes[ i + 1 ];
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B.set(
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positions[ 3 * index ],
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positions[ 3 * index + 1 ],
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positions[ 3 * index + 2 ] );
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index = indexes[ i + 2 ];
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C.set(
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positions[ 3 * index ],
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positions[ 3 * index + 1 ],
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positions[ 3 * index + 2 ] );
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C.sub( B );
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A.sub( B );
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const normal = C.cross( A ).normalize();
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for ( let j = 0; j < 3; j ++ ) {
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normals[ 3 * ( i + j ) ] = normal.x;
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normals[ 3 * ( i + j ) + 1 ] = normal.y;
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normals[ 3 * ( i + j ) + 2 ] = normal.z;
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}
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}
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}
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function mapPositionsToIndexes() {
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pointToIndexMap = Array( positions.length / 3 );
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for ( let i = 0; i < indexes.length; i ++ ) {
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const index = indexes[ i ];
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if ( pointToIndexMap[ index ] == null )
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pointToIndexMap[ index ] = [];
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pointToIndexMap[ index ].push( i );
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}
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}
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function edgeSplitToGroups( indexes, cutOff, firstIndex ) {
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A.set( normals[ 3 * firstIndex ], normals[ 3 * firstIndex + 1 ], normals[ 3 * firstIndex + 2 ] )
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.normalize();
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const result = {
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splitGroup: [],
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currentGroup: [ firstIndex ]
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};
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for ( const j of indexes ) {
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if ( j !== firstIndex ) {
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B.set( normals[ 3 * j ], normals[ 3 * j + 1 ], normals[ 3 * j + 2 ] )
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.normalize();
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if ( B.dot( A ) < cutOff )
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result.splitGroup.push( j );
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else
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result.currentGroup.push( j );
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}
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}
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return result;
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}
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function edgeSplit( indexes, cutOff, original = null ) {
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if ( indexes.length === 0 )
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return;
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const groupResults = [];
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for ( const index of indexes )
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groupResults.push( edgeSplitToGroups( indexes, cutOff, index ) );
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let result = groupResults[ 0 ];
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for ( const groupResult of groupResults )
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if ( groupResult.currentGroup.length > result.currentGroup.length )
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result = groupResult;
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if ( original != null )
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splitIndexes.push( {
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original: original,
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indexes: result.currentGroup
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} );
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if ( result.splitGroup.length )
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edgeSplit( result.splitGroup, cutOff, original || result.currentGroup[ 0 ] );
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}
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this.modify = function ( geometry, cutOffAngle ) {
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if ( ! geometry.isBufferGeometry ) {
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geometry = new THREE.BufferGeometry().fromGeometry( geometry );
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}
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if ( geometry.index == null )
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geometry = THREE.BufferGeometryUtils.mergeVertices( geometry );
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indexes = geometry.index.array;
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positions = geometry.getAttribute( "position" ).array;
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computeNormals();
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mapPositionsToIndexes();
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splitIndexes = [];
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for ( const vertexIndexes of pointToIndexMap )
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edgeSplit( vertexIndexes, Math.cos( cutOffAngle ) - 0.001 );
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const newPositions = new Float32Array( positions.length + 3 * splitIndexes.length );
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newPositions.set( positions );
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const offset = positions.length;
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const newIndexes = new Uint32Array( indexes.length );
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newIndexes.set( indexes );
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for ( let i = 0; i < splitIndexes.length; i ++ ) {
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const split = splitIndexes[ i ];
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const index = indexes[ split.original ];
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newPositions[ offset + 3 * i ] = positions[ 3 * index ];
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newPositions[ offset + 3 * i + 1 ] = positions[ 3 * index + 1 ];
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newPositions[ offset + 3 * i + 2 ] = positions[ 3 * index + 2 ];
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for ( const j of split.indexes )
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newIndexes[ j ] = offset / 3 + i;
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}
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geometry = new THREE.BufferGeometry();
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geometry.setAttribute( 'position', new THREE.BufferAttribute( newPositions, 3, true ) );
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geometry.setIndex( new THREE.BufferAttribute( newIndexes, 1 ) );
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return geometry;
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};
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};

‎examples/jsm/modifiers/EdgeSplitModifier.d.ts‎

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import { BufferGeometry, Geometry } from "../../../src/Three";
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export class EdgeSplitModifier {
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constructor();
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modify( geometry: Geometry, cutOffPoint: number ): BufferGeometry;
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}

‎examples/jsm/modifiers/EdgeSplitModifier.js‎

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import { BufferAttribute, BufferGeometry, Vector3 } from "../../../build/three.module.js";
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import { BufferGeometryUtils } from "../utils/BufferGeometryUtils.js";
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export function EdgeSplitModifier() {
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const A = new Vector3();
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const B = new Vector3();
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const C = new Vector3();
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let positions, normals;
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let indexes;
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let pointToIndexMap, splitIndexes;
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function computeNormals() {
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normals = new Float32Array( indexes.length * 3 );
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for ( let i = 0; i < indexes.length; i += 3 ) {
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let index = indexes[ i ];
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A.set(
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positions[ 3 * index ],
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positions[ 3 * index + 1 ],
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positions[ 3 * index + 2 ] );
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index = indexes[ i + 1 ];
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B.set(
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positions[ 3 * index ],
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positions[ 3 * index + 1 ],
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positions[ 3 * index + 2 ] );
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index = indexes[ i + 2 ];
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C.set(
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positions[ 3 * index ],
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positions[ 3 * index + 1 ],
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positions[ 3 * index + 2 ] );
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C.sub( B );
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A.sub( B );
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const normal = C.cross( A ).normalize();
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for ( let j = 0; j < 3; j ++ ) {
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normals[ 3 * ( i + j ) ] = normal.x;
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normals[ 3 * ( i + j ) + 1 ] = normal.y;
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normals[ 3 * ( i + j ) + 2 ] = normal.z;
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}
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}
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}
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function mapPositionsToIndexes() {
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pointToIndexMap = Array( positions.length / 3 );
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for ( let i = 0; i < indexes.length; i ++ ) {
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const index = indexes[ i ];
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if ( pointToIndexMap[ index ] == null )
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pointToIndexMap[ index ] = [];
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pointToIndexMap[ index ].push( i );
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}
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}
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function edgeSplitToGroups( indexes, cutOff, firstIndex ) {
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A.set( normals[ 3 * firstIndex ], normals[ 3 * firstIndex + 1 ], normals[ 3 * firstIndex + 2 ] )
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.normalize();
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const result = {
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splitGroup: [],
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currentGroup: [ firstIndex ]
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};
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for ( const j of indexes ) {
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if ( j !== firstIndex ) {
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B.set( normals[ 3 * j ], normals[ 3 * j + 1 ], normals[ 3 * j + 2 ] )
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.normalize();
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if ( B.dot( A ) < cutOff )
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result.splitGroup.push( j );
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else
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result.currentGroup.push( j );
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}
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}
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return result;
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}
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function edgeSplit( indexes, cutOff, original = null ) {
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if ( indexes.length === 0 )
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return;
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const groupResults = [];
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for ( const index of indexes )
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groupResults.push( edgeSplitToGroups( indexes, cutOff, index ) );
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let result = groupResults[ 0 ];
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for ( const groupResult of groupResults )
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if ( groupResult.currentGroup.length > result.currentGroup.length )
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result = groupResult;
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if ( original != null )
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splitIndexes.push( {
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original: original,
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indexes: result.currentGroup
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} );
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if ( result.splitGroup.length )
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edgeSplit( result.splitGroup, cutOff, original || result.currentGroup[ 0 ] );
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}
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this.modify = function ( geometry, cutOffAngle ) {
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if ( ! geometry.isBufferGeometry ) {
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geometry = new BufferGeometry().fromGeometry( geometry );
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}
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if ( geometry.index == null )
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geometry = BufferGeometryUtils.mergeVertices( geometry );
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indexes = geometry.index.array;
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positions = geometry.getAttribute( "position" ).array;
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computeNormals();
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mapPositionsToIndexes();
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splitIndexes = [];
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for ( const vertexIndexes of pointToIndexMap )
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edgeSplit( vertexIndexes, Math.cos( cutOffAngle ) - 0.001 );
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const newPositions = new Float32Array( positions.length + 3 * splitIndexes.length );
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newPositions.set( positions );
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const offset = positions.length;
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const newIndexes = new Uint32Array( indexes.length );
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newIndexes.set( indexes );
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for ( let i = 0; i < splitIndexes.length; i ++ ) {
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const split = splitIndexes[ i ];
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const index = indexes[ split.original ];
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newPositions[ offset + 3 * i ] = positions[ 3 * index ];
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newPositions[ offset + 3 * i + 1 ] = positions[ 3 * index + 1 ];
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newPositions[ offset + 3 * i + 2 ] = positions[ 3 * index + 2 ];
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for ( const j of split.indexes )
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newIndexes[ j ] = offset / 3 + i;
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}
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geometry = new BufferGeometry();
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geometry.setAttribute( 'position', new BufferAttribute( newPositions, 3, true ) );
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geometry.setIndex( new BufferAttribute( newIndexes, 1 ) );
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return geometry;
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};
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}

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