import type { ChaseCameraConfig, TopDownCameraConfig } from "./cameraConfig.js";
/** A screen region as fractions of the canvas, `[x, y, width, height]` in `0..1` with the origin at the top left. */
export type ViewportRect = readonly [number, number, number, number];
/** The follow camera an extra viewport runs; the primary seat keeps the game's main camera rig. */
export interface ViewportCameraConfig {
    /** Default: `"topDown"` when the game's main rig is top-down, otherwise `"chase"`. */
    rig?: "chase" | "topDown";
    chase?: ChaseCameraConfig;
    topDown?: TopDownCameraConfig;
}
/** One viewport: which local seat it shows and where. */
export interface ViewportDef {
    /** Local seat id (`"slot:0"`, `"slot:1"`, …) from `localPlayers(ctx)`. */
    slot: string;
    rect: ViewportRect;
    camera?: ViewportCameraConfig;
}
/** `defineGame({ viewports })`: split-screen layout for local seats. */
export interface ViewportsConfig {
    /** `"auto"` (default) splits the screen evenly across the seats currently joined; a list pins explicit rects. */
    layout?: "auto" | readonly ViewportDef[];
    /** Two-seat split: `"vertical"` puts them side by side (default), `"horizontal"` stacks them. */
    split?: "vertical" | "horizontal";
    /** Follow camera for seats whose viewport has none. */
    camera?: ViewportCameraConfig;
}
/** A viewport in canvas pixels with a bottom-left origin, ready for `gl.setViewport`/`setScissor`. */
export interface ViewportPixels {
    x: number;
    y: number;
    width: number;
    height: number;
}
/**
 * Even split-screen rects for seats in order: one fills the screen, two split side by side (or stacked),
 * three put the first on a full-width top half, four make a 2×2 grid, more fill a grid row by row.
 * @capability split-screen Split the screen into one viewport per local seat, each with its own follow camera.
 */
export declare function splitViewports(slots: readonly string[], split?: "vertical" | "horizontal"): ViewportDef[];
/** The viewports to draw for the seats currently joined: the explicit layout filtered to joined seats, or an even split. */
export declare function resolveViewports(config: ViewportsConfig | undefined, slots: readonly string[]): ViewportDef[];
/** Convert a top-left fractional rect into whole canvas pixels with a bottom-left origin; neighbours share edges exactly. */
export declare function viewportPixels(rect: ViewportRect, width: number, height: number): ViewportPixels;