import { Context } from './context';
import { Initializable } from './initializable';
import { NdcFillingTriangle } from './ndcfillingtriangle';
import { Program } from './program';
import { Shader } from './shader';
import { Texture2D } from './texture2d';
/**
 * Gaussian Filter implemented using a fragment shader.
 * Renders the filtered result into COLOR_ATTACHMENT0 of the currently bound framebuffer.
 * Does not support integer textures.
 * @todo: revisit this class design w.r.t. post planned catalogue of processing/filtering passes ...
 */
export declare class GaussFilter extends Initializable {
    protected static readonly _MAXKERNELSIZEHALF = 32;
    protected _kernelSize: GLsizei;
    protected _standardDeviation: GLfloat;
    protected _redistribute: GLboolean;
    protected _weights: [number, ...number[]] & {
        length: 32;
    } | undefined;
    protected _uDelta: WebGLUniformLocation;
    protected _uWeights: WebGLUniformLocation;
    protected _context: Context;
    protected _fragmentShader: Shader;
    protected _program: Program;
    protected _ndcTriangle: NdcFillingTriangle;
    protected _ndcTriangleShared: boolean;
    constructor(context: Context);
    /**
     * Recalculates the weights if necessary.
     * @returns - True if the weights were recalculated, false otherwise.
     */
    protected recalculateWeights(): boolean;
    /**
     * Size of the kernel.
     */
    get kernelSize(): GLsizei;
    /**
     * Sets the size of the kernel.
     * The kernel size has to be an odd integer.
     */
    set kernelSize(kernelSize: GLsizei);
    /**
     * Standard deviation used to calculate the weights.
     */
    get standardDeviation(): GLfloat;
    /**
     * Sets the standard deviation.
     */
    set standardDeviation(standardDeviation: GLfloat);
    /**
     * Parameter determining whether the weights outside of the kernel get redistributed on the kernel.
     */
    get redistribute(): GLboolean;
    /**
     * Sets the redistribute parameter.
     * If this is true then the sum of all weights inside the kernel is always 1.
     */
    set redistribute(redistribute: GLboolean);
    /**
     * Creates and initializes the gaussian filters resources.
     * @param ndcTriangle - If specified, assumed to be used as shared geometry. If none is specified, a ndc-filling
     * triangle will be created internally.
     */
    initialize(ndcTriangle?: NdcFillingTriangle): boolean;
    /**
     * Uninitializes the program and screen aligned triangle geometry, if it is not shared.
     */
    uninitialize(): void;
    /**
     * Filters the given texture in the given direction using the configured weights.
     * The weights will be recalculated if necessary.
     * @param texture - The float texture to filter.
     * @param direction - The direction to filter the texture in.
     */
    filter(texture: Texture2D, direction: GaussFilter.Direction): void;
}
export declare namespace GaussFilter {
    enum Direction {
        Horizontal = 0,
        Vertical = 1
    }
}