mirror of https://github.com/CesiumGS/obj2gltf.git
546 lines
18 KiB
JavaScript
546 lines
18 KiB
JavaScript
'use strict';
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const BUFFER_MAX_BYTE_LENGTH = require('buffer').constants.MAX_LENGTH;
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const Cesium = require('cesium');
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const getBufferPadded = require('./getBufferPadded');
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const getDefaultMaterial = require('./loadMtl').getDefaultMaterial;
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const Texture = require('./Texture');
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const defaultValue = Cesium.defaultValue;
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const defined = Cesium.defined;
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const WebGLConstants = Cesium.WebGLConstants;
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module.exports = createGltf;
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/**
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* Create a glTF from obj data.
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*
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* @param {Object} objData An object containing an array of nodes containing geometry information and an array of materials.
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* @param {Object} options The options object passed along from lib/obj2gltf.js
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* @returns {Object} A glTF asset.
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*
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* @private
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*/
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function createGltf(objData, options) {
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const nodes = objData.nodes;
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let materials = objData.materials;
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const name = objData.name;
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// Split materials used by primitives with different types of attributes
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materials = splitIncompatibleMaterials(nodes, materials, options);
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const gltf = {
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accessors : [],
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asset : {},
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buffers : [],
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bufferViews : [],
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extensionsUsed : [],
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extensionsRequired : [],
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images : [],
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materials : [],
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meshes : [],
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nodes : [],
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samplers : [],
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scene : 0,
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scenes : [],
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textures : []
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};
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gltf.asset = {
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generator : 'obj2gltf',
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version: '2.0'
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};
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gltf.scenes.push({
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nodes : []
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});
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const bufferState = {
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positionBuffers : [],
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normalBuffers : [],
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uvBuffers : [],
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indexBuffers : [],
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positionAccessors : [],
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normalAccessors : [],
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uvAccessors : [],
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indexAccessors : []
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};
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const uint32Indices = requiresUint32Indices(nodes);
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const nodesLength = nodes.length;
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for (let i = 0; i < nodesLength; ++i) {
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const node = nodes[i];
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const meshes = node.meshes;
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const meshesLength = meshes.length;
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if (meshesLength === 1) {
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const meshIndex = addMesh(gltf, materials, bufferState, uint32Indices, meshes[0], options);
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addNode(gltf, node.name, meshIndex, undefined);
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} else {
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// Add meshes as child nodes
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const parentIndex = addNode(gltf, node.name);
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for (let j = 0; j < meshesLength; ++j) {
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const mesh = meshes[j];
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const meshIndex = addMesh(gltf, materials, bufferState, uint32Indices, mesh, options);
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addNode(gltf, mesh.name, meshIndex, parentIndex);
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}
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}
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}
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if (gltf.images.length > 0) {
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gltf.samplers.push({
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magFilter : WebGLConstants.LINEAR,
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minFilter : WebGLConstants.NEAREST_MIPMAP_LINEAR,
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wrapS : WebGLConstants.REPEAT,
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wrapT : WebGLConstants.REPEAT
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});
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}
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addBuffers(gltf, bufferState, name, options.separate);
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if (options.specularGlossiness) {
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gltf.extensionsUsed.push('KHR_materials_pbrSpecularGlossiness');
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gltf.extensionsRequired.push('KHR_materials_pbrSpecularGlossiness');
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}
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if (options.unlit) {
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gltf.extensionsUsed.push('KHR_materials_unlit');
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gltf.extensionsRequired.push('KHR_materials_unlit');
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}
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return gltf;
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}
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function addCombinedBufferView(gltf, buffers, accessors, byteStride, target) {
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const length = buffers.length;
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if (length === 0) {
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return;
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}
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const bufferViewIndex = gltf.bufferViews.length;
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const previousBufferView = gltf.bufferViews[bufferViewIndex - 1];
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const byteOffset = defined(previousBufferView) ? previousBufferView.byteOffset + previousBufferView.byteLength : 0;
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let byteLength = 0;
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for (let i = 0; i < length; ++i) {
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const accessor = gltf.accessors[accessors[i]];
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accessor.bufferView = bufferViewIndex;
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accessor.byteOffset = byteLength;
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byteLength += buffers[i].length;
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}
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gltf.bufferViews.push({
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name : 'bufferView_' + bufferViewIndex,
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buffer : 0,
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byteLength : byteLength,
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byteOffset : byteOffset,
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byteStride : byteStride,
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target : target
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});
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}
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function addCombinedBuffers(gltf, bufferState, name) {
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addCombinedBufferView(gltf, bufferState.positionBuffers, bufferState.positionAccessors, 12, WebGLConstants.ARRAY_BUFFER);
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addCombinedBufferView(gltf, bufferState.normalBuffers, bufferState.normalAccessors, 12, WebGLConstants.ARRAY_BUFFER);
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addCombinedBufferView(gltf, bufferState.uvBuffers, bufferState.uvAccessors, 8, WebGLConstants.ARRAY_BUFFER);
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addCombinedBufferView(gltf, bufferState.indexBuffers, bufferState.indexAccessors, undefined, WebGLConstants.ELEMENT_ARRAY_BUFFER);
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let buffers = [];
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buffers = buffers.concat(bufferState.positionBuffers, bufferState.normalBuffers, bufferState.uvBuffers, bufferState.indexBuffers);
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const buffer = getBufferPadded(Buffer.concat(buffers));
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gltf.buffers.push({
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name : name,
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byteLength : buffer.length,
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extras : {
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_obj2gltf : {
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source : buffer
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}
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}
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});
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}
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function addSeparateBufferView(gltf, buffer, accessor, byteStride, target, name) {
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const bufferIndex = gltf.buffers.length;
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const bufferViewIndex = gltf.bufferViews.length;
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gltf.buffers.push({
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name : name + '_' + bufferIndex,
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byteLength : buffer.length,
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extras : {
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_obj2gltf : {
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source : buffer
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}
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}
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});
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gltf.bufferViews.push({
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buffer : bufferIndex,
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byteLength : buffer.length,
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byteOffset : 0,
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byteStride : byteStride,
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target : target
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});
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gltf.accessors[accessor].bufferView = bufferViewIndex;
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gltf.accessors[accessor].byteOffset = 0;
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}
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function addSeparateBufferViews(gltf, buffers, accessors, byteStride, target, name) {
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const length = buffers.length;
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for (let i = 0; i < length; ++i) {
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addSeparateBufferView(gltf, buffers[i], accessors[i], byteStride, target, name);
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}
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}
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function addSeparateBuffers(gltf, bufferState, name) {
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addSeparateBufferViews(gltf, bufferState.positionBuffers, bufferState.positionAccessors, 12, WebGLConstants.ARRAY_BUFFER, name);
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addSeparateBufferViews(gltf, bufferState.normalBuffers, bufferState.normalAccessors, 12, WebGLConstants.ARRAY_BUFFER, name);
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addSeparateBufferViews(gltf, bufferState.uvBuffers, bufferState.uvAccessors, 8, WebGLConstants.ARRAY_BUFFER, name);
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addSeparateBufferViews(gltf, bufferState.indexBuffers, bufferState.indexAccessors, undefined, WebGLConstants.ELEMENT_ARRAY_BUFFER, name);
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}
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function addBuffers(gltf, bufferState, name, separate) {
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const buffers = bufferState.positionBuffers.concat(bufferState.normalBuffers, bufferState.uvBuffers, bufferState.indexBuffers);
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const buffersLength = buffers.length;
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let buffersByteLength = 0;
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for (let i = 0; i < buffersLength; ++i) {
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buffersByteLength += buffers[i].length;
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}
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if (separate && (buffersByteLength > createGltf._getBufferMaxByteLength())) {
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// Don't combine buffers if the combined buffer will exceed the Node limit.
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addSeparateBuffers(gltf, bufferState, name);
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} else {
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addCombinedBuffers(gltf, bufferState, name);
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}
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}
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function addTexture(gltf, texture) {
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const imageName = texture.name;
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const textureName = texture.name;
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const imageIndex = gltf.images.length;
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const textureIndex = gltf.textures.length;
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gltf.images.push({
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name : imageName,
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extras : {
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_obj2gltf : texture
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}
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});
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gltf.textures.push({
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name : textureName,
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sampler : 0,
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source : imageIndex
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});
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return textureIndex;
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}
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function getTexture(gltf, texture) {
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let textureIndex;
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const name = texture.name;
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const textures = gltf.textures;
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const length = textures.length;
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for (let i = 0; i < length; ++i) {
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if (textures[i].name === name) {
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textureIndex = i;
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break;
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}
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}
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if (!defined(textureIndex)) {
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textureIndex = addTexture(gltf, texture);
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}
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return {
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index : textureIndex
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};
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}
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function cloneMaterial(material, removeTextures) {
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if (typeof material !== 'object') {
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return material;
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} else if (material instanceof Texture) {
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if (removeTextures) {
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return undefined;
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}
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return material;
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} else if (Array.isArray(material)) {
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const length = material.length;
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const clonedArray = new Array(length);
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for (let i = 0; i < length; ++i) {
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clonedArray[i] = cloneMaterial(material[i], removeTextures);
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}
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return clonedArray;
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}
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const clonedObject = {};
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for (const name in material) {
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if (material.hasOwnProperty(name)) {
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clonedObject[name] = cloneMaterial(material[name], removeTextures);
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}
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}
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return clonedObject;
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}
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function resolveTextures(gltf, material) {
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for (const name in material) {
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if (material.hasOwnProperty(name)) {
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const property = material[name];
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if (property instanceof Texture) {
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material[name] = getTexture(gltf, property);
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} else if (!Array.isArray(property) && (typeof property === 'object')) {
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resolveTextures(gltf, property);
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}
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}
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}
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}
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function addGltfMaterial(gltf, material, options) {
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resolveTextures(gltf, material);
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const materialIndex = gltf.materials.length;
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if (options.unlit) {
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if (!defined(material.extensions)) {
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material.extensions = {};
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}
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material.extensions.KHR_materials_unlit = {};
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}
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gltf.materials.push(material);
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return materialIndex;
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}
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function getMaterialByName(materials, materialName) {
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const materialsLength = materials.length;
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for (let i = 0; i < materialsLength; ++i) {
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if (materials[i].name === materialName) {
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return materials[i];
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}
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}
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}
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function getMaterialIndex(materials, materialName) {
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const materialsLength = materials.length;
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for (let i = 0; i < materialsLength; ++i) {
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if (materials[i].name === materialName) {
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return i;
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}
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}
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}
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function getOrCreateGltfMaterial(gltf, materials, materialName, options) {
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const material = getMaterialByName(materials, materialName);
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let materialIndex = getMaterialIndex(gltf.materials, materialName);
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if (!defined(materialIndex)) {
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materialIndex = addGltfMaterial(gltf, material, options);
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}
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return materialIndex;
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}
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function primitiveInfoMatch(a, b) {
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return a.hasUvs === b.hasUvs &&
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a.hasNormals === b.hasNormals;
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}
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function getSplitMaterialName(originalMaterialName, primitiveInfo, primitiveInfoByMaterial) {
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let splitMaterialName = originalMaterialName;
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let suffix = 2;
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while (defined(primitiveInfoByMaterial[splitMaterialName])) {
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if (primitiveInfoMatch(primitiveInfo, primitiveInfoByMaterial[splitMaterialName])) {
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break;
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}
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splitMaterialName = originalMaterialName + '-' + suffix++;
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}
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return splitMaterialName;
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}
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function splitIncompatibleMaterials(nodes, materials, options) {
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const splitMaterials = [];
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const primitiveInfoByMaterial = {};
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const nodesLength = nodes.length;
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for (let i = 0; i < nodesLength; ++i) {
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const meshes = nodes[i].meshes;
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const meshesLength = meshes.length;
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for (let j = 0; j < meshesLength; ++j) {
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const primitives = meshes[j].primitives;
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const primitivesLength = primitives.length;
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for (let k = 0; k < primitivesLength; ++k) {
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const primitive = primitives[k];
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const hasUvs = primitive.uvs.length > 0;
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const hasNormals = primitive.normals.length > 0;
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const primitiveInfo = {
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hasUvs : hasUvs,
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hasNormals : hasNormals
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};
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const originalMaterialName = defaultValue(primitive.material, 'default');
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const splitMaterialName = getSplitMaterialName(originalMaterialName, primitiveInfo, primitiveInfoByMaterial);
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primitive.material = splitMaterialName;
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primitiveInfoByMaterial[splitMaterialName] = primitiveInfo;
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let splitMaterial = getMaterialByName(splitMaterials, splitMaterialName);
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if (defined(splitMaterial)) {
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continue;
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}
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const originalMaterial = getMaterialByName(materials, originalMaterialName);
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if (defined(originalMaterial)) {
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splitMaterial = cloneMaterial(originalMaterial, !hasUvs);
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} else {
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splitMaterial = getDefaultMaterial(options);
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}
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splitMaterial.name = splitMaterialName;
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splitMaterials.push(splitMaterial);
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}
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}
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}
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return splitMaterials;
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}
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function addVertexAttribute(gltf, array, components, name) {
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const count = array.length / components;
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const minMax = array.getMinMax(components);
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const type = (components === 3 ? 'VEC3' : 'VEC2');
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const accessor = {
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name : name,
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componentType : WebGLConstants.FLOAT,
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count : count,
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min : minMax.min,
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max : minMax.max,
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type : type
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};
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const accessorIndex = gltf.accessors.length;
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gltf.accessors.push(accessor);
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return accessorIndex;
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}
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function addIndexArray(gltf, array, uint32Indices, name) {
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const componentType = uint32Indices ? WebGLConstants.UNSIGNED_INT : WebGLConstants.UNSIGNED_SHORT;
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const count = array.length;
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const minMax = array.getMinMax(1);
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const accessor = {
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name : name,
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componentType : componentType,
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count : count,
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min : minMax.min,
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max : minMax.max,
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type : 'SCALAR'
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};
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const accessorIndex = gltf.accessors.length;
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gltf.accessors.push(accessor);
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return accessorIndex;
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}
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function requiresUint32Indices(nodes) {
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const nodesLength = nodes.length;
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for (let i = 0; i < nodesLength; ++i) {
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const meshes = nodes[i].meshes;
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const meshesLength = meshes.length;
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for (let j = 0; j < meshesLength; ++j) {
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const primitives = meshes[j].primitives;
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const primitivesLength = primitives.length;
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for (let k = 0; k < primitivesLength; ++k) {
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// Reserve the 65535 index for primitive restart
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const vertexCount = primitives[k].positions.length / 3;
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if (vertexCount > 65534) {
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return true;
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}
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}
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}
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}
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return false;
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}
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function addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primitive, index, options) {
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const hasPositions = primitive.positions.length > 0;
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const hasNormals = primitive.normals.length > 0;
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const hasUVs = primitive.uvs.length > 0;
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const attributes = {};
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if (hasPositions) {
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const accessorIndex = addVertexAttribute(gltf, primitive.positions, 3, mesh.name + '_' + index + '_positions');
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attributes.POSITION = accessorIndex;
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bufferState.positionBuffers.push(primitive.positions.toFloatBuffer());
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bufferState.positionAccessors.push(accessorIndex);
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}
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if (hasNormals) {
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const accessorIndex = addVertexAttribute(gltf, primitive.normals, 3, mesh.name + '_' + index + '_normals');
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attributes.NORMAL = accessorIndex;
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bufferState.normalBuffers.push(primitive.normals.toFloatBuffer());
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bufferState.normalAccessors.push(accessorIndex);
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}
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if (hasUVs) {
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const accessorIndex = addVertexAttribute(gltf, primitive.uvs, 2, mesh.name + '_' + index + '_texcoords');
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attributes.TEXCOORD_0 = accessorIndex;
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bufferState.uvBuffers.push(primitive.uvs.toFloatBuffer());
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bufferState.uvAccessors.push(accessorIndex);
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}
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const indexAccessorIndex = addIndexArray(gltf, primitive.indices, uint32Indices, mesh.name + '_' + index + '_indices');
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const indexBuffer = uint32Indices ? primitive.indices.toUint32Buffer() : primitive.indices.toUint16Buffer();
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bufferState.indexBuffers.push(indexBuffer);
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bufferState.indexAccessors.push(indexAccessorIndex);
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// Unload resources
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primitive.positions = undefined;
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primitive.normals = undefined;
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primitive.uvs = undefined;
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primitive.indices = undefined;
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const materialIndex = getOrCreateGltfMaterial(gltf, materials, primitive.material, options);
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return {
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attributes : attributes,
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indices : indexAccessorIndex,
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material : materialIndex,
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mode : WebGLConstants.TRIANGLES
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};
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}
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function addMesh(gltf, materials, bufferState, uint32Indices, mesh, options) {
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const gltfPrimitives = [];
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const primitives = mesh.primitives;
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const primitivesLength = primitives.length;
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for (let i = 0; i < primitivesLength; ++i) {
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gltfPrimitives.push(addPrimitive(gltf, materials, bufferState, uint32Indices, mesh, primitives[i], i, options));
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}
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const gltfMesh = {
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name : mesh.name,
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primitives : gltfPrimitives
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};
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const meshIndex = gltf.meshes.length;
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gltf.meshes.push(gltfMesh);
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return meshIndex;
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}
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function addNode(gltf, name, meshIndex, parentIndex) {
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const node = {
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name : name,
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mesh : meshIndex
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};
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const nodeIndex = gltf.nodes.length;
|
|
gltf.nodes.push(node);
|
|
|
|
if (defined(parentIndex)) {
|
|
const parentNode = gltf.nodes[parentIndex];
|
|
if (!defined(parentNode.children)) {
|
|
parentNode.children = [];
|
|
}
|
|
parentNode.children.push(nodeIndex);
|
|
} else {
|
|
gltf.scenes[gltf.scene].nodes.push(nodeIndex);
|
|
}
|
|
|
|
return nodeIndex;
|
|
}
|
|
|
|
// Exposed for testing
|
|
createGltf._getBufferMaxByteLength = function() {
|
|
return BUFFER_MAX_BYTE_LENGTH;
|
|
};
|