message: expose RenderTarget.depthRenderbuffer
diff: /**
  - * Copyright (c) 2018-2021 mol* contributors, licensed under MIT, See LICENSE file for more info.
  + * Copyright (c) 2018-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  */
  @@ -9,6 +9,7 @@ import { createNullTexture, Texture, TextureFilter } from './texture';
  import { createNullFramebuffer, Framebuffer } from './framebuffer';
  import { WebGLResources } from './resources';
  import { GLRenderingContext, isWebGL2 } from './compat';
  +import { Renderbuffer } from './renderbuffer';
  const getNextRenderTargetId = idFactory();
  @@ -16,6 +17,7 @@ export interface RenderTarget {
  readonly id: number
  readonly texture: Texture
  readonly framebuffer: Framebuffer
  + readonly depthRenderbuffer: Renderbuffer | null
  getWidth: () => number
  getHeight: () => number
  @@ -54,6 +56,7 @@ export function createRenderTarget(gl: GLRenderingContext, resources: WebGLResou
  id: getNextRenderTargetId(),
  texture: targetTexture,
  framebuffer,
  + depthRenderbuffer,
  getWidth: () => _width,
  getHeight: () => _height,
  @@ -90,6 +93,7 @@ export function createNullRenderTarget(gl: GLRenderingContext): RenderTarget {
  id: getNextRenderTargetId(),
  texture: createNullTexture(gl),
  framebuffer: createNullFramebuffer(),
  + depthRenderbuffer: null,
  getWidth: () => 0,
  getHeight: () => 0,
  