three
Version:
JavaScript 3D library
227 lines (137 loc) • 4.41 kB
JavaScript
import { zipSync, strToU8 } from '../libs/fflate.module.min.js';
class USDZExporter {
parse( scene ) {
let output = buildHeader();
const materials = {};
scene.traverse( ( object ) => {
if ( object.isMesh ) {
materials[ object.material.uuid ] = object.material;
output += buildXform( object, buildMesh( object.geometry, object.material ) );
}
} );
output += buildMaterials( materials );
return zipSync( { 'model.usda': strToU8( output ) }, { level: 0 } );
}
}
//
function buildHeader() {
return `#usda 1.0
(
doc = "Three.js"
metersPerUnit = 1
upAxis = "Y"
)
`;
}
// Xform
function buildXform( object, define ) {
const name = object.name || 'Xform1';
const transform = buildMatrix( object.matrixWorld );
return `def Xform "${ name }"
{
matrix4d xformOp:transform = ${ transform }
uniform token[] xformOpOrder = ["xformOp:transform"]
${ define }
}
`;
}
function buildMatrix( matrix ) {
const array = matrix.elements;
return `( ${ buildMatrixRow( array, 0 ) }, ${ buildMatrixRow( array, 4 ) }, ${ buildMatrixRow( array, 8 ) }, ${ buildMatrixRow( array, 12 ) } )`;
}
function buildMatrixRow( array, offset ) {
return `(${ array[ offset + 0 ] }, ${ array[ offset + 1 ] }, ${ array[ offset + 2 ] }, ${ array[ offset + 3 ] })`;
}
// Mesh
function buildMesh( geometry, material ) {
const name = geometry.name || 'Mesh1';
const attributes = geometry.attributes;
const count = attributes.position.count;
return `def Mesh "${ name }"
{
int[] faceVertexCounts = [${ buildMeshVertexCount( geometry ) }]
int[] faceVertexIndices = [${ buildMeshVertexIndices( geometry ) }]
rel material:binding = </_materials/Material_${ material.id }>
normal3f[] normals = [${ buildVector3Array( attributes.normal, count )}] (
interpolation = "faceVarying"
)
point3f[] points = [${ buildVector3Array( attributes.position, count )}]
texCoord2f[] primvars:UVMap = [${ buildVector2Array( attributes.uv, count )}] (
interpolation = "faceVarying"
)
uniform token subdivisionScheme = "none"
}
`;
}
function buildMeshVertexCount( geometry ) {
const count = geometry.index !== null ? geometry.index.array.length : geometry.attributes.position.count;
return Array( count / 3 ).fill( 3 ).join( ', ' );
}
function buildMeshVertexIndices( geometry ) {
if ( geometry.index !== null ) {
return geometry.index.array.join( ', ' );
}
const array = [];
const length = geometry.attributes.position.count;
for ( let i = 0; i < length; i ++ ) {
array.push( i );
}
return array.join( ', ' );
}
function buildVector3Array( attribute, count ) {
if ( attribute === undefined ) {
console.warn( 'USDZExporter: Normals missing.' );
return Array( count ).fill( '(0, 0, 0)' ).join( ', ' );
}
const array = [];
const data = attribute.array;
for ( let i = 0; i < data.length; i += 3 ) {
array.push( `(${ data[ i + 0 ] }, ${ data[ i + 1 ] }, ${ data[ i + 2 ] })` );
}
return array.join( ', ' );
}
function buildVector2Array( attribute, count ) {
if ( attribute === undefined ) {
console.warn( 'USDZExporter: UVs missing.' );
return Array( count ).fill( '(0, 0)' ).join( ', ' );
}
const array = [];
const data = attribute.array;
for ( let i = 0; i < data.length; i += 2 ) {
array.push( `(${ data[ i + 0 ] }, ${ data[ i + 1 ] })` );
}
return array.join( ', ' );
}
// Materials
function buildMaterials( materials ) {
const array = [];
for ( const uuid in materials ) {
const material = materials[ uuid ];
array.push( buildMaterial( material ) );
}
return `def "_materials"
{
${ array.join( '' ) }
}
`;
}
function buildMaterial( material ) {
return `
def Material "Material_${ material.id }"
{
token outputs:surface.connect = </_materials/Material_${ material.id }/previewShader.outputs:surface>
def Shader "previewShader"
{
uniform token info:id = "UsdPreviewSurface"
color3f inputs:diffuseColor = ${ buildColor( material.color ) }
float inputs:metallic = ${ material.metalness }
float inputs:roughness = ${ material.roughness }
token outputs:surface
}
}
`;
}
function buildColor( color ) {
return `(${ color.r }, ${ color.g }, ${ color.b })`;
}
export { USDZExporter };