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@gltf-transform/extensions

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Adds extension support to @gltf-transform/core

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import { Extension, PropertyType, type ReaderContext, type WriterContext } from '@gltf-transform/core'; import { KHR_MATERIALS_EMISSIVE_STRENGTH } from '../constants.js'; import { EmissiveStrength } from './emissive-strength.js'; /** * [KHR_materials_emissive_strength](https://github.com/KhronosGroup/gltf/blob/main/extensions/2.0/Khronos/KHR_materials_emissive_strength/) * defines emissive strength and enables high-dynamic-range (HDR) emissive materials. * * ![Illustration](/media/extensions/khr-materials-emissive-strength.jpg) * * > _**Figure:** Cubes with emissive color #59BCF3 and emissive strength * > increasing from 1 to 256 nits, left to right. Rendered in [three.js](https://threejs.org/), * > with independent point lighting and a bloom effect. * > Source: [Don McCurdy](https://www.donmccurdy.com/2024/04/27/emission-and-bloom/)._ * * The core glTF 2.0 material model includes {@link Material.setEmissiveFactor `emissiveFactor`} * and {@link Material.setEmissiveTexture `emissiveTexture`} to control the color and intensity * of the light being emitted by the material, clamped to the range [0.0, 1.0]. However, in * PBR environments with HDR reflections and lighting, stronger emission effects may be desirable. * * In this extension, a new {@link EmissiveStrength.setEmissiveStrength `emissiveStrength`} scalar * factor is supplied, which governs the upper limit of emissive strength per material and may be * given arbitrarily high values. * * For implementations where a physical light unit is needed, the units for the multiplicative * product of the emissive texture and factor are candela per square meter (cd / m2), sometimes * called _nits_. Many realtime rendering engines simplify this calculation by assuming that an * emissive factor of 1.0 results in a fully exposed pixel. * * Properties: * - {@link EmissiveStrength} * * ### Example * * ```typescript * import { KHRMaterialsEmissiveStrength, EmissiveStrength } from '@gltf-transform/extensions'; * * // Create an Extension attached to the Document. * const emissiveStrengthExtension = document.createExtension(KHRMaterialsEmissiveStrength); * * // Create EmissiveStrength property. * const emissiveStrength = emissiveStrengthExtension * .createEmissiveStrength().setEmissiveStrength(5.0); * * // Assign to a Material. * material.setExtension('KHR_materials_emissive_strength', emissiveStrength); * ``` */ export declare class KHRMaterialsEmissiveStrength extends Extension { static readonly EXTENSION_NAME: typeof KHR_MATERIALS_EMISSIVE_STRENGTH; readonly extensionName: typeof KHR_MATERIALS_EMISSIVE_STRENGTH; readonly prereadTypes: PropertyType[]; readonly prewriteTypes: PropertyType[]; /** Creates a new EmissiveStrength property for use on a {@link Material}. */ createEmissiveStrength(): EmissiveStrength; /** @hidden */ read(_context: ReaderContext): this; /** @hidden */ write(_context: WriterContext): this; /** @hidden */ preread(context: ReaderContext): this; /** @hidden */ prewrite(context: WriterContext): this; }