threepipe
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A modern 3D viewer framework built on top of three.js, written in TypeScript, designed to make creating high-quality, modular, and extensible 3D experiences on the web simple and enjoyable.
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text/typescript
import type {GLTFLoaderPlugin, GLTFParser} from 'three/examples/jsm/loaders/GLTFLoader.js'
import type {MeshStandardMaterial} from 'three'
import type {GLTFExporterPlugin, GLTFWriter} from 'three/examples/jsm/exporters/GLTFExporter.js'
/**
* Alpha Map Extension
*
* alphaTexture is added to the material
* This is separate from the alpha in base color texture. This is used when that is not supported in the viewer
*
* Specification: https://threepipe.org/docs/gltf-extensions/WEBGI_materials_alphamap.html
*/
export class GLTFMaterialsAlphaMapExtension {
static readonly WebGiMaterialsAlphaMapExtension = 'WEBGI_materials_alphamap'
static Import = (parser: GLTFParser): GLTFLoaderPlugin=> new GLTFMaterialsAlphaMapExtensionImport(parser)
static Export = (writer: GLTFWriter): GLTFExporterPlugin => new GLTFMaterialsAlphaMapExtensionExport(writer)
// see GLTFDracoExportPlugin
static Textures: Record<string, string|number> = {
alphaTexture: 'G',
}
}
class GLTFMaterialsAlphaMapExtensionImport {
public name: string
constructor(public parser: GLTFParser) {
this.name = GLTFMaterialsAlphaMapExtension.WebGiMaterialsAlphaMapExtension
}
// getMaterialType(materialIndex: number) { // todo: required?
//
// const parser = this.parser
// const materialDef = parser.json.materials[ materialIndex ]
//
// if (!materialDef.extensions || !materialDef.extensions[ this.name ]) return null
//
// return MeshPhysicalMaterial
//
// }
async extendMaterialParams(materialIndex: number, materialParams: any) {
const parser = this.parser
const materialDef = parser.json.materials[ materialIndex ]
if (!materialDef.extensions || !materialDef.extensions[ this.name ]) {
return Promise.resolve()
}
const pending = []
const extension = materialDef.extensions[ this.name ]
if (extension.alphaTexture !== undefined) {
pending.push(parser.assignTexture(materialParams, 'alphaMap', extension.alphaTexture))
}
return Promise.all(pending)
}
}
export type {GLTFMaterialsAlphaMapExtensionImport}
class GLTFMaterialsAlphaMapExtensionExport {
public name: string
constructor(public writer: GLTFWriter) {
this.name = GLTFMaterialsAlphaMapExtension.WebGiMaterialsAlphaMapExtension
}
writeMaterial(material: MeshStandardMaterial, materialDef: any) {
if (!material.isMeshStandardMaterial || !material.alphaMap) return
const writer = this.writer
const extensionsUsed = writer.extensionsUsed
const extensionDef: any = {}
if (material.alphaMap && writer.checkEmptyMap(material.alphaMap)) {
const alphaMapDef = {index: writer.processTexture(material.alphaMap)}
writer.applyTextureTransform(alphaMapDef, material.alphaMap)
extensionDef.alphaTexture = alphaMapDef
}
if (!Object.keys(extensionDef)) return
materialDef.extensions = materialDef.extensions || {}
materialDef.extensions[ this.name ] = extensionDef
extensionsUsed[ this.name ] = true
}
}
export type {GLTFMaterialsAlphaMapExtensionExport}