function getAttachmentPointForFormat(format) {
    return attachmentsByFormat[format];
  }
The options for a framebuffer attachment.

Note: For a `format` that is a texture include all the texture
options from {@link module:twgl.TextureOptions} for example
`min`, `mag`, `clamp`, etc... Note that unlike {@link module:twgl.TextureOptions}
`auto` defaults to `false` for attachment textures but `min` and `mag` default
to `gl.LINEAR` and `wrap` defaults to `CLAMP_TO_EDGE`

@typedef {Object} AttachmentOptions
@property {number} [attach] The attachment point. Defaults
  to `gl.COLOR_ATTACTMENT0 + ndx` unless type is a depth or stencil type
  then it's gl.DEPTH_ATTACHMENT or `gl.DEPTH_STENCIL_ATTACHMENT` depending
  on the format or attachment type.
@property {number} [format] The format. If one of `gl.RGBA4`,
  `gl.RGB565`, `gl.RGB5_A1`, `gl.DEPTH_COMPONENT16`,
  `gl.STENCIL_INDEX8` or `gl.DEPTH_STENCIL` then will create a
  renderbuffer. Otherwise will create a texture. Default = `gl.RGBA`
@property {number} [type] The type. Used for texture. Default = `gl.UNSIGNED_BYTE`.
@property {number} [target] The texture target for `gl.framebufferTexture2D`.
  Defaults to `gl.TEXTURE_2D`. Set to appropriate face for cube maps.
@property {number} [level] level for `gl.framebufferTexture2D`. Defaults to 0.
@property {WebGLObject} [attachment] An existing renderbuffer or texture.
   If provided will attach this Object. This allows you to share
   attachemnts across framebuffers.
@memberOf module:twgl