/**
 * GlassRenderer — WebGL rendering pipeline for the liquid glass effect.
 *
 * Manages a single offscreen WebGL canvas, shader programs, and a pool
 * of local-sized FBOs for blur passes. Each panel render crops just the
 * padded region behind that panel, uploads only that region, and shades
 * the glass effect into the matching per-element canvas.
 */
import type { GlassConfig } from './defaults.js';
export declare class GlassRenderer {
    readonly canvas: HTMLCanvasElement;
    readonly gl: WebGLRenderingContext;
    private readonly cropCanvas;
    private readonly cropCtx;
    private blitP;
    private blitU;
    private blurP;
    private blurU;
    private glassP;
    private glassU;
    private quadBuf;
    private panelBuf;
    private readonly fboCache;
    private activeFBOs;
    private bgTex;
    width: number;
    height: number;
    contextLost: boolean;
    private _onContextLost;
    private _onContextRestored;
    constructor();
    private _initPrograms;
    private _initBuffers;
    resize(width: number, height: number): void;
    uploadAndBlur(sourceCanvas: HTMLCanvasElement, sourceX: number, sourceY: number, width: number, height: number, blurAmount: number): void;
    renderGlassPanel(config: GlassConfig, width: number, height: number, dpr: number): void;
    clear(): void;
    destroy(): void;
    private _setActiveSize;
    private _makeFBO;
    private _freeFBO;
    private _freeFBOSet;
    private _compile;
    private _link;
    private _uloc;
    private _drawQuad;
}
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