function PassState(context) {
  /**
   * The context used to execute commands for this pass.
   *
   * @type {Context}
   */
  this.context = context;

  /**
   * The framebuffer to render to.  This framebuffer is used unless a {@link DrawCommand}
   * or {@link ClearCommand} explicitly define a framebuffer, which is used for off-screen
   * rendering.
   *
   * @type {Framebuffer}
   * @default undefined
   */
  this.framebuffer = undefined;

  /**
   * When defined, this overrides the blending property of a {@link DrawCommand}'s render state.
   * This is used to, for example, to allow the renderer to turn off blending during the picking pass.
   * <p>
   * When this is <code>undefined</code>, the {@link DrawCommand}'s property is used.
   * </p>
   *
   * @type {boolean}
   * @default undefined
   */
  this.blendingEnabled = undefined;

  /**
   * When defined, this overrides the scissor test property of a {@link DrawCommand}'s render state.
   * This is used to, for example, to allow the renderer to scissor out the pick region during the picking pass.
   * <p>
   * When this is <code>undefined</code>, the {@link DrawCommand}'s property is used.
   * </p>
   *
   * @type {object}
   * @default undefined
   */
  this.scissorTest = undefined;

  /**
   * The viewport used when one is not defined by a {@link DrawCommand}'s render state.
   * @type {BoundingRectangle}
   * @default undefined
   */
  this.viewport = undefined;
}
The state for a particular rendering pass.  This is used to supplement the state
in a command being executed.

@private
@constructor