import { GLclampf4, GLsizei2 } from './tuples';
import { Bindable } from './bindable';
import { Context } from './context';
import { AbstractObject } from './object';
import { Renderbuffer } from './renderbuffer';
import { Texture2D } from './texture2d';
/**
 * WebGL Framebuffer base implementation providing size accessors and requiring for bind, unbind, resize, validity,
 * and initialization implementations.
 * ```
 * @todo add usage example
 * ```
 */
export declare class Framebuffer extends AbstractObject<WebGLFramebuffer> implements Bindable {
    /**
     * Default framebuffer, e.g., used for unbind.
     */
    static readonly DEFAULT_FRAMEBUFFER: undefined;
    /**
     * Access to all attached renderbuffer objects.
     */
    protected _buffersByAttachment: Map<number, Renderbuffer>;
    /**
     * Access to all attached texture objects.
     */
    protected _texturesByAttachment: Map<number, Texture2D>;
    /**
     * RGBA color, depth value, or stencil value used for clearing the
     * associated buffer.
     */
    protected _clearDepth: GLfloat;
    protected _clearStencil: GLint;
    protected _clearColors: Array<GLclampf4>;
    /**
     * Queue of all draw buffers that are to be cleared on `clear`.
     */
    protected _colorClearQueue: number[];
    /** @see {@link drawBuffers} */
    protected _drawBuffers: number[];
    protected _drawBuffersChanged: boolean;
    /**
     * Depending on the webgl version and provided bitmask, clears attachments of the framebuffer. Note that this
     * function is set/unset to es2Clear or es3Clear on initialization/uninitialization.
     * @param mask - Bitmask specifying which bits are to be cleared (and thereby which attachments).
     * @param bind - Allows to skip binding the framebuffer (e.g., when binding is handled outside).
     * @param unbind - Allows to skip unbinding the framebuffer (e.g., when binding is handled outside).
     * @param colorClearQueue - allows to specify a specific queue of color attachments to be cleared. The webgl1
     * implementation ignores this parameter. If no parameter is given, the webgl2 implementation clears all color
     * attachments.
     */
    clear: ((mask: GLbitfield, bind?: boolean, unbind?: boolean, colorClearQueue?: Array<GLint>) => void);
    /**
     * Returns a string describing the given status of a framebuffer object.
     * @param context - Context for valid GLenums.
     * @param status - A framebuffer's status.
     */
    protected static statusString(context: Context, status: GLenum): string;
    /**
     * Create a framebuffer object on the GPU and attaches all given renderable objects (either renderbuffer or
     * texture) to the framebuffer object.
     * @param attachments - tuples that associate an attachment to its actual render object, either a renderbuffer or
     * texture, e.g., `[ gl.COLOR_ATTACHMENT0, someTexture ]`.
     */
    protected create(attachments: Array<[GLenum, Renderbuffer | Texture2D]>): WebGLFramebuffer | undefined;
    /**
     * Delete the framebuffer object on the GPU. This should have the reverse effect of `create`.
     */
    protected delete(): void;
    /**
     * WebGL1 implementation for clearing framebuffer attachments.
     * @param mask - A GLbitfield bitwise OR mask that indicates the buffers to be cleared.
     * @param bind - Allows to skip binding the framebuffer (e.g., when binding is handled outside).
     * @param unbind - Allows to skip unbinding the framebuffer (e.g., when binding is handled outside).
     */
    protected es2Clear(mask: GLbitfield, bind?: boolean, unbind?: boolean): void;
    /**
     * WebGL2 implementation for clearing framebuffer attachments.
     * @param mask - A GLbitfield bitwise OR mask that indicates the buffers to be cleared.
     * @param bind - Allows to skip binding the framebuffer (e.g., when binding is handled outside).
     * @param unbind - Allows to skip unbinding the framebuffer (e.g., when binding is handled outside).
     * @param colorClearQueue - Allows to specify a specific queue of color attachments to be cleared. If no
     * parameter is given, the webgl2 implementation clears all color attachments.
     */
    protected es3Clear(mask: GLbitfield, bind?: boolean, unbind?: boolean, colorClearQueue?: Array<GLint>): void;
    /**
     *
     * @param attachment -
     */
    protected hasAttachment(attachment: GLenum): boolean;
    /**
     * Binds the framebuffer object as framebuffer to the provided target.
     * @param target - Specifying the binding point (target).
     */
    bind(target?: GLenum): void;
    /**
     * Binds the default back buffer as framebuffer to the provided target.
     * @param target - Specifying the binding point (target).
     */
    unbind(target?: GLenum): void;
    /**
     * Sets the clear color used for clearing a draw buffer. In order to have transparency working, the canvas needs
     * to have the alpha attribute enabled. This stage also supports premultiplied alpha, which is applied
     * automatically when the context's `premultipliedAlpha` attribute is set.
     * @param color - RGBA clear color.
     * @param drawBuffer - The draw buffer index. If no index is provided, the color will be applied to all buffers.
     */
    clearColor(color: GLclampf4, drawBuffer?: GLint): void;
    clearDepth(depth: GLfloat): void;
    clearStencil(stencil: GLint): void;
    /**
     * Access to attached textures, identified by a valid framebuffer attachment.
     * @param attachment - The attachment to request the texture object of.
     * @returns - A texture object if one exists for the given attachment, otherwise undefined.
     */
    texture(attachment: GLenum): Texture2D | undefined;
    /**
     * Forwards a resize to all attachments, renderbuffers and textures.
     * @param width - Targeted/new width for all attachments in px.
     * @param height - Targeted/new height for all attachments in px.
     * @param bind - Allows to skip binding the specific attachment (e.g., when binding is handled outside).
     * @param unbind - Allows to skip unbinding the specific attachment (e.g., when binding is handled outside).
     */
    resize(width: GLsizei, height: GLsizei, bind?: boolean, unbind?: boolean): void;
    /**
     * Readonly access to the framebuffer width in pixel. If the width of the attachments are not all identical,
     * the minimal width as the renderable width of this framebuffer is returned.
     * @returns - The minimal width of the renderable width over all attachments.
     */
    get width(): GLsizei;
    /**
     * Readonly access to the framebuffer height in pixel. If the height of the attachments are not all identical,
     * the minimal height as the renderable height of this framebuffer is returned.
     * @returns - The minimal height of the renderable height over all attachments.
     */
    get height(): GLsizei;
    /**
     * Convenience getter for the 2-tuple containing the texture's width and height.
     * @see {@link width}
     * @see {@link heigth}
     */
    get size(): GLsizei2;
    /**
     * Set one or multiple draw buffers.
     * @param attachments - Array of attachment identifier (e.g., gl.COLOR_ATTACHMENT0).
     */
    set drawBuffers(attachments: Array<GLenum>);
    /**
     * Used to remember which attachments are available as potential draw buffers.
     */
    get drawBuffers(): Array<GLenum>;
}