message: Make hte palette optional in `CharCellGrid`
diff: @@ -64,7 +64,7 @@ export class CharCellGrid {
  private _dataView: DataView;
  private _uint8View: Uint8Array;
  - constructor(public readonly width: number, public readonly height: number, private readonly _palette: number[]) {
  + constructor(public readonly width: number, public readonly height: number, private readonly _palette: number[]=null) {
  this._rawBuffer = new ArrayBuffer(width * height * CELL_SIZE_BYTES);
  this._dataView = new DataView(this._rawBuffer);
  this._uint8View = new Uint8Array(this._rawBuffer);
  @@ -147,9 +147,11 @@ export class CharCellGrid {
  this._dataView.setUint16(offset + OFFSET_FG_CLUT_INDEX, index);
  + if (this._palette != null) {
  const rgba = this._palette[index];
  this._dataView.setUint32(offset + OFFSET_FG, rgba);
  }
  + }
  getFgClutIndex(x: number, y: number): number {
  const offset = (y * this.width + x) * CELL_SIZE_BYTES;
  @@ -164,9 +166,11 @@ export class CharCellGrid {
  this._dataView.setUint16(offset + OFFSET_BG_CLUT_INDEX, index);
  + if (this._palette != null) {
  const rgba = this._palette[index];
  this._dataView.setUint32(offset + OFFSET_BG, rgba);
  }
  + }
  getBgClutIndex(x: number, y: number): number {
  const offset = (y * this.width + x) * CELL_SIZE_BYTES;
  