three
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JavaScript 3D library
271 lines (186 loc) • 7.3 kB
JavaScript
import { BufferAttribute } from 'three';
/**
* A plugin for `3d-tiles-renderer` that computes creased vertex normals for the
* geometry of each loaded tile: smooth normals everywhere except where faces meet
* at an angle greater than the crease angle. Useful for photogrammetry tile sets
* like Google Photorealistic 3D Tiles which come without vertex normals.
*
* The normals are computed in a Web Worker so tile processing doesn't block the
* main thread. Tiles are displayed once their normals are ready.
*
* ```js
* tiles.registerPlugin( new TileCreasedNormalsPlugin( { creaseAngle: Math.PI / 6 } ) );
* ```
*
* @three_import import { TileCreasedNormalsPlugin } from 'three/addons/misc/TileCreasedNormalsPlugin.js';
*/
class TileCreasedNormalsPlugin {
/**
* Constructs a new plugin.
*
* @param {Object} [options] - The configuration options.
* @param {number} [options.creaseAngle=Math.PI/3] - The crease angle in radians.
*/
constructor( { creaseAngle = Math.PI / 3 } = {} ) {
/**
* The crease angle in radians.
*
* @type {number}
*/
this.creaseAngle = creaseAngle;
this._requestId = 0;
this._pending = new Map();
const workerCode = `
${ computeCreasedNormals.toString() }
onmessage = ( { data } ) => {
const { id, positions, creaseAngle } = data;
const normals = computeCreasedNormals( positions, creaseAngle );
postMessage( { id, positions, normals }, [ positions.buffer, normals.buffer ] );
};
`;
this._worker = new Worker( URL.createObjectURL( new Blob( [ workerCode ] ) ) );
this._worker.onmessage = ( { data } ) => {
this._pending.get( data.id )( data );
this._pending.delete( data.id );
};
}
/**
* Called by the tiles renderer for each loaded tile model. The tile is
* displayed once the returned promise resolves.
*
* @param {Object3D} scene - The tile model.
* @return {Promise} A promise that resolves when all geometries have creased normals.
*/
processTileModel( scene ) {
const promises = [];
scene.traverse( ( mesh ) => {
if ( mesh.geometry ) {
promises.push( this._processMesh( mesh ) );
}
} );
return Promise.all( promises );
}
_processMesh( mesh ) {
const geometry = mesh.geometry.index ? mesh.geometry.toNonIndexed() : mesh.geometry;
const positions = geometry.attributes.position.array;
const id = this._requestId ++;
this._worker.postMessage( { id, positions, creaseAngle: this.creaseAngle }, [ positions.buffer ] );
return new Promise( ( resolve ) => {
this._pending.set( id, ( { positions, normals } ) => {
geometry.setAttribute( 'position', new BufferAttribute( positions, 3 ) );
geometry.setAttribute( 'normal', new BufferAttribute( normals, 3 ) );
mesh.geometry = geometry;
resolve();
} );
} );
}
/**
* Called by the tiles renderer when the plugin is unregistered or the
* tiles renderer is disposed.
*/
dispose() {
this._worker.terminate();
}
}
// Computes creased normals for non-indexed triangle positions. The function is
// self-contained so it can be serialized into the worker.
function computeCreasedNormals( positions, creaseAngle ) {
const creaseDot = Math.cos( creaseAngle );
const hashMultiplier = ( 1 + 1e-10 ) * 1e2;
const vertexCount = positions.length / 3;
const faceCount = vertexCount / 3;
// compute the normal of each face
const faceNormals = new Float64Array( faceCount * 3 );
for ( let f = 0; f < faceCount; f ++ ) {
const f9 = 9 * f;
const ax = positions[ f9 + 0 ], ay = positions[ f9 + 1 ], az = positions[ f9 + 2 ];
const bx = positions[ f9 + 3 ], by = positions[ f9 + 4 ], bz = positions[ f9 + 5 ];
const cx = positions[ f9 + 6 ], cy = positions[ f9 + 7 ], cz = positions[ f9 + 8 ];
const v1x = cx - bx, v1y = cy - by, v1z = cz - bz;
const v2x = ax - bx, v2y = ay - by, v2z = az - bz;
const nx = v1y * v2z - v1z * v2y;
const ny = v1z * v2x - v1x * v2z;
const nz = v1x * v2y - v1y * v2x;
const invLength = 1 / ( Math.sqrt( nx * nx + ny * ny + nz * nz ) || 1 );
faceNormals[ 3 * f + 0 ] = nx * invLength;
faceNormals[ 3 * f + 1 ] = ny * invLength;
faceNormals[ 3 * f + 2 ] = nz * invLength;
}
// assign an id to each vertex, sharing the id between vertices with the same
// quantized position via an open-addressed hash table (slots hold id + 1, 0 means empty)
const vertexIds = new Int32Array( vertexCount );
const quantized = new Int32Array( vertexCount * 3 );
let tableSize = 1;
while ( tableSize < vertexCount * 2 ) tableSize <<= 1;
const tableMask = tableSize - 1;
const table = new Int32Array( tableSize );
let uniqueCount = 0;
for ( let i = 0; i < vertexCount; i ++ ) {
const i3 = 3 * i;
const qx = ~ ~ ( positions[ i3 + 0 ] * hashMultiplier );
const qy = ~ ~ ( positions[ i3 + 1 ] * hashMultiplier );
const qz = ~ ~ ( positions[ i3 + 2 ] * hashMultiplier );
let slot = ( Math.imul( qx, 73856093 ) ^ Math.imul( qy, 19349663 ) ^ Math.imul( qz, 83492791 ) ) & tableMask;
while ( true ) {
const id = table[ slot ];
if ( id === 0 ) {
const q3 = 3 * uniqueCount;
quantized[ q3 + 0 ] = qx;
quantized[ q3 + 1 ] = qy;
quantized[ q3 + 2 ] = qz;
table[ slot ] = uniqueCount + 1;
vertexIds[ i ] = uniqueCount ++;
break;
}
const q3 = 3 * ( id - 1 );
if ( quantized[ q3 + 0 ] === qx && quantized[ q3 + 1 ] === qy && quantized[ q3 + 2 ] === qz ) {
vertexIds[ i ] = id - 1;
break;
}
slot = ( slot + 1 ) & tableMask;
}
}
// bucket the faces surrounding each unique vertex position
const bucketOffsets = new Int32Array( uniqueCount + 1 );
for ( let i = 0; i < vertexCount; i ++ ) bucketOffsets[ vertexIds[ i ] + 1 ] ++;
for ( let i = 0; i < uniqueCount; i ++ ) bucketOffsets[ i + 1 ] += bucketOffsets[ i ];
const bucketFaces = new Int32Array( vertexCount );
const bucketCursors = bucketOffsets.slice( 0, uniqueCount );
for ( let f = 0; f < faceCount; f ++ ) {
const f3 = 3 * f;
bucketFaces[ bucketCursors[ vertexIds[ f3 + 0 ] ] ++ ] = f;
bucketFaces[ bucketCursors[ vertexIds[ f3 + 1 ] ] ++ ] = f;
bucketFaces[ bucketCursors[ vertexIds[ f3 + 2 ] ] ++ ] = f;
}
// average the normals of the faces surrounding each vertex if they are within the
// provided crease threshold
const normalArray = new Float32Array( vertexCount * 3 );
for ( let f = 0; f < faceCount; f ++ ) {
const f3 = 3 * f;
const nx = faceNormals[ f3 + 0 ];
const ny = faceNormals[ f3 + 1 ];
const nz = faceNormals[ f3 + 2 ];
for ( let n = 0; n < 3; n ++ ) {
const i = f3 + n;
const id = vertexIds[ i ];
let sumX = 0, sumY = 0, sumZ = 0;
for ( let k = bucketOffsets[ id ], end = bucketOffsets[ id + 1 ]; k < end; k ++ ) {
const o3 = 3 * bucketFaces[ k ];
const ox = faceNormals[ o3 + 0 ];
const oy = faceNormals[ o3 + 1 ];
const oz = faceNormals[ o3 + 2 ];
if ( nx * ox + ny * oy + nz * oz > creaseDot ) {
sumX += ox;
sumY += oy;
sumZ += oz;
}
}
const invLength = 1 / ( Math.sqrt( sumX * sumX + sumY * sumY + sumZ * sumZ ) || 1 );
normalArray[ 3 * i + 0 ] = sumX * invLength;
normalArray[ 3 * i + 1 ] = sumY * invLength;
normalArray[ 3 * i + 2 ] = sumZ * invLength;
}
}
return normalArray;
}
export { TileCreasedNormalsPlugin };