import {
BufferAttribute,
BufferGeometry,
Vector3
} from 'three';
import * as BufferGeometryUtils from '../utils/BufferGeometryUtils.js';
const _A = new Vector3();
const _B = new Vector3();
const _C = new Vector3();
class EdgeSplitModifier {
modify( geometry, cutOffAngle, tryKeepNormals = true ) {
function computeNormals() {
normals = new Float32Array( indexes.length * 3 );
for ( let i = 0; i < indexes.length; i += 3 ) {
let index = indexes[ i ];
_A.set(
positions[ 3 * index ],
positions[ 3 * index + 1 ],
positions[ 3 * index + 2 ] );
index = indexes[ i + 1 ];
_B.set(
positions[ 3 * index ],
positions[ 3 * index + 1 ],
positions[ 3 * index + 2 ] );
index = indexes[ i + 2 ];
_C.set(
positions[ 3 * index ],
positions[ 3 * index + 1 ],
positions[ 3 * index + 2 ] );
_C.sub( _B );
_A.sub( _B );
const normal = _C.cross( _A ).normalize();
for ( let j = 0; j < 3; j ++ ) {
normals[ 3 * ( i + j ) ] = normal.x;
normals[ 3 * ( i + j ) + 1 ] = normal.y;
normals[ 3 * ( i + j ) + 2 ] = normal.z;
}
}
}
function mapPositionsToIndexes() {
pointToIndexMap = Array( positions.length / 3 );
for ( let i = 0; i < indexes.length; i ++ ) {
const index = indexes[ i ];
if ( pointToIndexMap[ index ] == null ) {
pointToIndexMap[ index ] = [];
}
pointToIndexMap[ index ].push( i );
}
}
function edgeSplitToGroups( indexes, cutOff, firstIndex ) {
_A.set( normals[ 3 * firstIndex ], normals[ 3 * firstIndex + 1 ], normals[ 3 * firstIndex + 2 ] ).normalize();
const result = {
splitGroup: [],
currentGroup: [ firstIndex ]
};
for ( const j of indexes ) {
if ( j !== firstIndex ) {
_B.set( normals[ 3 * j ], normals[ 3 * j + 1 ], normals[ 3 * j + 2 ] ).normalize();
if ( _B.dot( _A ) < cutOff ) {
result.splitGroup.push( j );
} else {
result.currentGroup.push( j );
}
}
}
return result;
}
function edgeSplit( indexes, cutOff, original = null ) {
if ( indexes.length === 0 ) return;
const groupResults = [];
for ( const index of indexes ) {
groupResults.push( edgeSplitToGroups( indexes, cutOff, index ) );
}
let result = groupResults[ 0 ];
for ( const groupResult of groupResults ) {
if ( groupResult.currentGroup.length > result.currentGroup.length ) {
result = groupResult;
}
}
if ( original != null ) {
splitIndexes.push( {
original: original,
indexes: result.currentGroup
} );
}
if ( result.splitGroup.length ) {
edgeSplit( result.splitGroup, cutOff, original || result.currentGroup[ 0 ] );
}
}
let hadNormals = false;
let oldNormals = null;
if ( geometry.attributes.normal ) {
hadNormals = true;
geometry = geometry.clone();
if ( tryKeepNormals === true && geometry.index !== null ) {
oldNormals = geometry.attributes.normal.array;
}
geometry.deleteAttribute( 'normal' );
}
if ( geometry.index == null ) {
geometry = BufferGeometryUtils.mergeVertices( geometry );
}
const indexes = geometry.index.array;
const positions = geometry.getAttribute( 'position' ).array;
let normals;
let pointToIndexMap;
computeNormals();
mapPositionsToIndexes();
const splitIndexes = [];
for ( const vertexIndexes of pointToIndexMap ) {
edgeSplit( vertexIndexes, Math.cos( cutOffAngle ) - 0.001 );
}
const newAttributes = {};
for ( const name of Object.keys( geometry.attributes ) ) {
const oldAttribute = geometry.attributes[ name ];
const newArray = new oldAttribute.array.constructor( ( indexes.length + splitIndexes.length ) * oldAttribute.itemSize );
newArray.set( oldAttribute.array );
newAttributes[ name ] = new BufferAttribute( newArray, oldAttribute.itemSize, oldAttribute.normalized );
}
const newIndexes = new Uint32Array( indexes.length );
newIndexes.set( indexes );
for ( let i = 0; i < splitIndexes.length; i ++ ) {
const split = splitIndexes[ i ];
const index = indexes[ split.original ];
for ( const attribute of Object.values( newAttributes ) ) {
for ( let j = 0; j < attribute.itemSize; j ++ ) {
attribute.array[ ( indexes.length + i ) * attribute.itemSize + j ] =
attribute.array[ index * attribute.itemSize + j ];
}
}
for ( const j of split.indexes ) {
newIndexes[ j ] = indexes.length + i;
}
}
geometry = new BufferGeometry();
geometry.setIndex( new BufferAttribute( newIndexes, 1 ) );
for ( const name of Object.keys( newAttributes ) ) {
geometry.setAttribute( name, newAttributes[ name ] );
}
if ( hadNormals ) {
geometry.computeVertexNormals();
if ( oldNormals !== null ) {
const changedNormals = new Array( oldNormals.length / 3 ).fill( false );
for ( const splitData of splitIndexes )
changedNormals[ splitData.original ] = true;
for ( let i = 0; i < changedNormals.length; i ++ ) {
if ( changedNormals[ i ] === false ) {
for ( let j = 0; j < 3; j ++ )
geometry.attributes.normal.array[ 3 * i + j ] = oldNormals[ 3 * i + j ];
}
}
}
}
return geometry;
}
}
export { EdgeSplitModifier };
