Last active
November 7, 2025 16:22
-
-
Save wwwtyro/62b3d03c25602bca15dd2bf1967416fd to your computer and use it in GitHub Desktop.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| // MIT License | |
| // | |
| // Copyright 2025 Rye Terrell | |
| // | |
| // Permission is hereby granted, free of charge, to any person obtaining a copy | |
| // of this software and associated documentation files (the “Software”), to deal | |
| // in the Software without restriction, including without limitation the rights | |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| // copies of the Software, and to permit persons to whom the Software is | |
| // furnished to do so, subject to the following conditions: | |
| // | |
| // THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| // SOFTWARE. | |
| import { type TypedArray, WebIO } from "@gltf-transform/core"; | |
| import { vec3 } from "gl-matrix"; | |
| export interface Mesh { | |
| positions: TypedArray; | |
| normals: TypedArray | null | undefined; | |
| colors: TypedArray; | |
| count: number; | |
| baseColorImage?: HTMLImageElement; | |
| uvs?: TypedArray; | |
| indices?: TypedArray; | |
| } | |
| export async function loadGLB(url: string) { | |
| const response = await fetch(url); | |
| const arrayBuffer = await response.arrayBuffer(); | |
| const io = new WebIO({ credentials: "include" }); | |
| const doc = await io.readBinary(new Uint8Array(arrayBuffer)); | |
| const primitives: Mesh[] = []; | |
| const imageCache = new Map<Uint8Array, HTMLImageElement>(); | |
| const meshes = doc.getRoot().listMeshes(); | |
| for (const mesh of meshes) { | |
| for (const primitive of mesh.listPrimitives()) { | |
| const positionsAttribute = primitive.getAttribute("POSITION"); | |
| if (!positionsAttribute) { | |
| throw new Error(`Positions missing in asset ${url}`); | |
| } | |
| const positions = positionsAttribute.getArray(); | |
| if (positions === null) { | |
| throw new Error(`Positions null in asset ${url}`); | |
| } | |
| const vertexCount = positionsAttribute.getCount(); | |
| const color0 = primitive.getAttribute("COLOR_0")?.getArray() ?? undefined; | |
| const uvs = primitive.getAttribute("TEXCOORD_0")?.getArray() ?? undefined; | |
| const indices = primitive.getIndices()?.getArray() ?? undefined; | |
| const normals = primitive.getAttribute("NORMAL")?.getArray() ?? generateFlatNormals(positions, indices); | |
| const material = primitive.getMaterial(); | |
| if (!material) { | |
| throw new Error(`Material missing in asset ${url}`); | |
| } | |
| const baseColor = material.getBaseColorFactor(); | |
| const colors = color0 ?? new Float32Array(vertexCount * 3); | |
| if (!color0) { | |
| for (let i = 0; i < vertexCount; i++) { | |
| colors[i * 3 + 0] = baseColor[0]; | |
| colors[i * 3 + 1] = baseColor[1]; | |
| colors[i * 3 + 2] = baseColor[2]; | |
| } | |
| } | |
| const texture = material.getBaseColorTexture(); | |
| let baseColorImage: HTMLImageElement | undefined; | |
| if (texture) { | |
| const image = texture.getImage(); | |
| if (image !== null) { | |
| if (!imageCache.has(image)) { | |
| const element = await createImageElementFromBuffer(image, texture.getMimeType()); | |
| imageCache.set(image, element); | |
| } | |
| baseColorImage = imageCache.get(image); | |
| if (baseColorImage === undefined) { | |
| throw new Error(`baseColorImage undefined for asset ${url}`); | |
| } | |
| } | |
| } | |
| primitives.push({ | |
| positions, | |
| normals, | |
| colors, | |
| uvs, | |
| count: indices ? indices.length : vertexCount, | |
| baseColorImage, | |
| indices, | |
| }); | |
| } | |
| } | |
| return primitives; | |
| } | |
| function createImageElementFromBuffer(array: Uint8Array, mimeType: string) { | |
| return new Promise<HTMLImageElement>((resolve) => { | |
| const blob = new Blob([array as BlobPart], { type: mimeType }); | |
| const url = URL.createObjectURL(blob); | |
| const img = new Image(); | |
| img.onload = () => { | |
| resolve(img); | |
| }; | |
| img.src = url; | |
| }); | |
| } | |
| function generateFlatNormals(positions: TypedArray, indices: TypedArray | undefined): Float32Array { | |
| const normals = new Float32Array(positions.length); | |
| if (indices === undefined) { | |
| indices = generateSimpleIndices(positions.length / 3); | |
| } | |
| for (let i = 0; i < indices.length; i += 3) { | |
| const i0 = indices[i] * 3; | |
| const i1 = indices[i + 1] * 3; | |
| const i2 = indices[i + 2] * 3; | |
| const v0 = vec3.fromValues(positions[i0], positions[i0 + 1], positions[i0 + 2]); | |
| const v1 = vec3.fromValues(positions[i1], positions[i1 + 1], positions[i1 + 2]); | |
| const v2 = vec3.fromValues(positions[i2], positions[i2 + 1], positions[i2 + 2]); | |
| const edge1 = vec3.subtract(vec3.create(), v1, v0); | |
| const edge2 = vec3.subtract(vec3.create(), v2, v0); | |
| const normal = vec3.cross(vec3.create(), edge1, edge2); | |
| vec3.normalize(normal, normal); | |
| normals.set(normal, i0); | |
| } | |
| return normals; | |
| } | |
| function generateSimpleIndices(count: number): TypedArray { | |
| const indices = new Uint32Array(count); | |
| for (let i = 0; i < count; i++) { | |
| indices[i] = i; | |
| } | |
| return indices; | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment