import { Observable } from "../Misc/observable";
import type { Nullable } from "../types";
import type { Scene } from "../scene";
import { Vector2 } from "../Maths/math.vector";
import { Color4 } from "../Maths/math.color";
import type { BaseTexture } from "../Materials/Textures/baseTexture";
import type { RenderTargetTexture } from "../Materials/Textures/renderTargetTexture";
import "../Shaders/layer.fragment";
import "../Shaders/layer.vertex";
/**
 * This represents a full screen 2d layer.
 * This can be useful to display a picture in the  background of your scene for instance.
 * @see https://www.babylonjs-playground.com/#08A2BS#1
 */
export declare class Layer {
    /**
     * Define the name of the layer.
     */
    name: string;
    /**
     * Define the texture the layer should display.
     */
    texture: Nullable<BaseTexture>;
    /**
     * Is the layer in background or foreground.
     */
    isBackground: boolean;
    private _applyPostProcess;
    /**
     * Determines if the layer is drawn before (true) or after (false) post-processing.
     * If the layer is background, it is always before.
     */
    set applyPostProcess(value: boolean);
    get applyPostProcess(): boolean;
    /**
     * Define the color of the layer (instead of texture).
     */
    color: Color4;
    /**
     * Define the scale of the layer in order to zoom in out of the texture.
     */
    scale: Vector2;
    /**
     * Define an offset for the layer in order to shift the texture.
     */
    offset: Vector2;
    /**
     * Define the alpha blending mode used in the layer in case the texture or color has an alpha.
     */
    alphaBlendingMode: number;
    /**
     * Define if the layer should alpha test or alpha blend with the rest of the scene.
     * Alpha test will not mix with the background color in case of transparency.
     * It will either use the texture color or the background depending on the alpha value of the current pixel.
     */
    alphaTest: boolean;
    /**
     * Define a mask to restrict the layer to only some of the scene cameras.
     */
    layerMask: number;
    /**
     * Define the list of render target the layer is visible into.
     */
    renderTargetTextures: RenderTargetTexture[];
    /**
     * Define if the layer is only used in renderTarget or if it also
     * renders in the main frame buffer of the canvas.
     */
    renderOnlyInRenderTargetTextures: boolean;
    /**
     * Define if the layer is enabled (ie. should be displayed). Default: true
     */
    isEnabled: boolean;
    private _scene;
    private _vertexBuffers;
    private _indexBuffer;
    private _drawWrapper;
    private _previousDefines;
    /**
     * An event triggered when the layer is disposed.
     */
    onDisposeObservable: Observable<Layer>;
    private _onDisposeObserver;
    /**
     * Back compatibility with callback before the onDisposeObservable existed.
     * The set callback will be triggered when the layer has been disposed.
     */
    set onDispose(callback: () => void);
    /**
     * An event triggered before rendering the scene
     */
    onBeforeRenderObservable: Observable<Layer>;
    private _onBeforeRenderObserver;
    /**
     * Back compatibility with callback before the onBeforeRenderObservable existed.
     * The set callback will be triggered just before rendering the layer.
     */
    set onBeforeRender(callback: () => void);
    /**
     * An event triggered after rendering the scene
     */
    onAfterRenderObservable: Observable<Layer>;
    private _onAfterRenderObserver;
    /**
     * Back compatibility with callback before the onAfterRenderObservable existed.
     * The set callback will be triggered just after rendering the layer.
     */
    set onAfterRender(callback: () => void);
    /**
     * Instantiates a new layer.
     * This represents a full screen 2d layer.
     * This can be useful to display a picture in the  background of your scene for instance.
     * @see https://www.babylonjs-playground.com/#08A2BS#1
     * @param name Define the name of the layer in the scene
     * @param imgUrl Define the url of the texture to display in the layer
     * @param scene Define the scene the layer belongs to
     * @param isBackground Defines whether the layer is displayed in front or behind the scene
     * @param color Defines a color for the layer
     */
    constructor(
    /**
     * Define the name of the layer.
     */
    name: string, imgUrl: Nullable<string>, scene: Nullable<Scene>, isBackground?: boolean, color?: Color4);
    private _createIndexBuffer;
    /** @internal */
    _rebuild(): void;
    /**
     * Checks if the layer is ready to be rendered
     * @returns true if the layer is ready. False otherwise.
     */
    isReady(): boolean | undefined;
    /**
     * Renders the layer in the scene.
     */
    render(): void;
    /**
     * Disposes and releases the associated resources.
     */
    dispose(): void;
}