import { GpuShaderDefinition } from './gpu/contract';

/**
 * Make a user-defined shader findable by its `name`, so preset JSON can reference it as `type: 'Halo'`.
 *
 * Returns the definition, so it can wrap `defineShader` inline. Registering the same object
 * again does nothing. A different definition under a taken name replaces it (live editing,
 * hot reload) and notifies `onShaderRegistered` listeners. `<CustomShader>` calls this for
 * you on mount; `createShader(canvas, preset, {components: [Halo]})` is the other way to
 * make a name resolvable without registering globally.
 *
 * @example
 * ```ts
 * import {createShader} from 'shaders/js'
 * import {Halo} from './halo'
 *
 * registerShader(Halo)
 * const shader = await createShader(canvas, {components: [{type: 'Halo', props: {bands: 6}}]})
 * ```
 * @see defineShader, unregisterShader, getRegisteredShader, onShaderRegistered
 */
export declare function registerShader<T extends GpuShaderDefinition<any>>(definition: T): T;
/**
 * Forget a user-defined shader by name.
 *
 * Does nothing for a name that was never registered. Listeners from `onShaderRegistered` are
 * told with a `null` definition.
 *
 * @example
 * ```ts
 * unregisterShader('Halo')
 * ```
 * @see registerShader
 */
export declare function unregisterShader(name: string): void;
/**
 * Look up a user-defined shader by name.
 *
 * Returns `undefined` for unknown names. The library's own shaders are not in this registry.
 *
 * @example
 * ```ts
 * const definition = getRegisteredShader('Halo')
 * ```
 * @see getRegisteredShaders, registerShader
 */
export declare function getRegisteredShader(name: string): GpuShaderDefinition | undefined;
/**
 * Every user-defined shader currently registered, oldest first.
 *
 * @example
 * ```ts
 * const names = getRegisteredShaders().map((d) => d.name)
 * ```
 * @see getRegisteredShader, onShaderRegistered
 */
export declare function getRegisteredShaders(): GpuShaderDefinition[];
/**
 * Be told when a user-defined shader is registered, replaced or removed.
 *
 * The listener gets the name and the new definition, or `null` on removal. Returns a function
 * that unsubscribes. Useful for a component picker or a live editor that lists custom shaders.
 *
 * @example
 * ```ts
 * const stop = onShaderRegistered((name, definition) => refreshPicker())
 * ```
 * @see registerShader, getRegisteredShaders
 */
export declare function onShaderRegistered(listener: (name: string, definition: GpuShaderDefinition | null) => void): () => void;
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