@gltf-transform/extensions
Version:
Adds extension support to @gltf-transform/core
64 lines (63 loc) • 3.11 kB
TypeScript
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.
*
* 
*
* > _**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;
}