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https://git.mirrors.martin98.com/https://github.com/google/draco
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81d73904ac
The latest version of Draco brings many new enhancements to improve the development experience: * Stable API release * Support for npm Javascript package management * Javascript based encoder * Generalized metadata for meshes and point clouds * Now supporting material properties included along with encoded file * Improved compression rates: * 15% better compression on smaller models * 40% better compression of normals * Performance improvements (~10% faster encoding, decoding) * Reduced GPU memory usage: * Option to store decoded quantized attributes * Support for triangle strip connectivity on decoded meshes * iOS 9 Javascript decoder * Bitstream specification now available
103 lines
3.6 KiB
JavaScript
103 lines
3.6 KiB
JavaScript
// Copyright 2017 The Draco Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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/**
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* @fileoverview Helper class implementing various utilities for THREE.js
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* geometry.
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*/
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function GeometryHelper() {}
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GeometryHelper.prototype = {
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constructor: GeometryHelper,
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// Computes vertex normals on THREE.js buffer geometry, even when the mesh
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// uses triangle strip connectivity.
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computeVertexNormals: function (bufferGeometry) {
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if (bufferGeometry.drawMode === THREE.TrianglesDrawMode) {
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bufferGeometry.computeVertexNormals();
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return;
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} else if (bufferGeometry.drawMode === THREE.TriangleStripDrawMode) {
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if (bufferGeometry.attributes.position === undefined) {
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return;
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}
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const inPositions = bufferGeometry.attributes.position.array;
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if (bufferGeometry.attributes.normal === undefined) {
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bufferGeometry.addAttribute(
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'normal',
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new THREE.BufferAttribute(new Float32Array(inPositions.length),
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3));
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} else {
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// Reset existing normals to zero.
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const array = bufferGeometry.attributes.normal.array;
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for (let i = 0; i < array.length; ++i) {
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array[ i ] = 0;
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}
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}
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let outNormals = bufferGeometry.attributes.normal.array;
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let pos0 = new THREE.Vector3();
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let pos1 = new THREE.Vector3();
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let pos2 = new THREE.Vector3();
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let posDif0 = new THREE.Vector3(), posDif1 = new THREE.Vector3();
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let localNormal = new THREE.Vector3();
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const stripIndices = bufferGeometry.index.array;
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for (let i = 2; i < stripIndices.length; ++i) {
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let index0 = stripIndices[i - 2] * 3;
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let index1 = stripIndices[i - 1] * 3;
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let index2 = stripIndices[i] * 3;
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// Skip degenerate triangles.
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if (index0 === index1 || index0 === index2 || index1 === index2) {
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continue;
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}
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if ((i & 1) !== 0) {
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// Swap index 1 and 0 on odd indexed triangles.
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const tmpIndex = index1;
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index1 = index2;
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index2 = tmpIndex;
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}
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// Get position values.
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pos0.fromArray(inPositions, index0);
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pos1.fromArray(inPositions, index1);
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pos2.fromArray(inPositions, index2);
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// Position differences
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posDif0.subVectors(pos2, pos0);
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posDif1.subVectors(pos1, pos0);
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// Weighted normal.
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localNormal.crossVectors(posDif1, posDif0);
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// Update normals on vertices
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outNormals[index0] += localNormal.x;
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outNormals[index0 + 1] += localNormal.y;
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outNormals[index0 + 2] += localNormal.z;
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outNormals[index1] += localNormal.x;
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outNormals[index1 + 1] += localNormal.y;
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outNormals[index1 + 2] += localNormal.z;
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outNormals[index2] += localNormal.x;
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outNormals[index2 + 1] += localNormal.y;
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outNormals[index2 + 2] += localNormal.z;
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}
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bufferGeometry.normalizeNormals();
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bufferGeometry.attributes.normal.needsUpdate = true;
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}
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},
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};
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