three.js/src/textures/Source.js

import { ImageUtils } from '../extras/ImageUtils.js';
import * as MathUtils from '../math/MathUtils.js';

class Source {

	constructor( data = null ) {

		this.isSource = true;

		this.uuid = MathUtils.generateUUID();

		this.data = data;

		this.version = 0;

	}

	set needsUpdate( value ) {

		if ( value === true ) this.version ++;

	}

	toJSON( meta ) {

		const isRootObject = ( meta === undefined || typeof meta === 'string' );

		if ( ! isRootObject && meta.images[ this.uuid ] !== undefined ) {

			return meta.images[ this.uuid ];

		}

		const output = {
			uuid: this.uuid,
			url: ''
		};

		const data = this.data;

		if ( data !== null ) {

			let url;

			if ( Array.isArray( data ) ) {

				// cube texture

				url = [];

				for ( let i = 0, l = data.length; i < l; i ++ ) {

					if ( data[ i ].isDataTexture ) {

						url.push( serializeImage( data[ i ].image ) );

					} else {

						url.push( serializeImage( data[ i ] ) );

					}

				}

			} else {

				// texture

				url = serializeImage( data );

			}

			output.url = url;

		}

		if ( ! isRootObject ) {

			meta.images[ this.uuid ] = output;

		}

		return output;

	}

}

function serializeImage( image ) {

	if ( ( typeof HTMLImageElement !== 'undefined' && image instanceof HTMLImageElement ) ||
		( typeof HTMLCanvasElement !== 'undefined' && image instanceof HTMLCanvasElement ) ||
		( typeof ImageBitmap !== 'undefined' && image instanceof ImageBitmap ) ) {

		// default images

		return ImageUtils.getDataURL( image );

	} else {

		if ( image.data ) {

			// images of DataTexture

			return {
				data: Array.prototype.slice.call( image.data ),
				width: image.width,
				height: image.height,
				type: image.data.constructor.name
			};

		} else {

			console.warn( 'THREE.Texture: Unable to serialize Texture.' );
			return {};

		}

	}

}

export { Source };