message: store colors in glb using 8 bits per channel
diff: @@ -22,6 +22,7 @@ const v3toArray = Vec3.toArray;
  // https://github.com/KhronosGroup/glTF/tree/master/specification/2.0
  +const UNSIGNED_BYTE = 5121;
  const UNSIGNED_INT = 5125;
  const FLOAT = 5126;
  const ARRAY_BUFFER = 34962;
  @@ -52,7 +53,7 @@ export class GlbExporter extends MeshExporter<GlbData> {
  return [ min, max ];
  }
  - private addBuffer(buffer: ArrayBuffer, componentType: number, type: string, count: number, target: number, min?: any, max?: any) {
  + private addBuffer(buffer: ArrayBuffer, componentType: number, type: string, count: number, target: number, min?: any, max?: any, normalized?: boolean) {
  this.binaryBuffer.push(buffer);
  const bufferViewOffset = this.bufferViews.length;
  @@ -72,7 +73,8 @@ export class GlbExporter extends MeshExporter<GlbData> {
  count,
  type,
  min,
  - max
  + max,
  + normalized
  });
  return accessorOffset;
  }
  @@ -130,7 +132,7 @@ export class GlbExporter extends MeshExporter<GlbData> {
  const dTransparency = values.dTransparency.ref.value;
  const tTransparency = values.tTransparency.ref.value;
  - const colorArray = new Float32Array(vertexCount * 4);
  + const colorArray = new Uint8Array(vertexCount * 4);
  for (let i = 0; i < vertexCount; ++i) {
  let color: Color;
  @@ -174,8 +176,8 @@ export class GlbExporter extends MeshExporter<GlbData> {
  }
  color = Color.sRGBToLinear(color);
  - Color.toArrayNormalized(color, colorArray, i * 4);
  - colorArray[i * 4 + 3] = alpha;
  + Color.toArray(color, colorArray, i * 4);
  + colorArray[i * 4 + 3] = Math.round(alpha * 255);
  }
  let colorBuffer = colorArray.buffer;
  @@ -183,7 +185,7 @@ export class GlbExporter extends MeshExporter<GlbData> {
  colorBuffer = flipByteOrder(new Uint8Array(colorBuffer), 4);
  }
  - return this.addBuffer(colorBuffer, FLOAT, 'VEC4', vertexCount, ARRAY_BUFFER);
  + return this.addBuffer(colorBuffer, UNSIGNED_BYTE, 'VEC4', vertexCount, ARRAY_BUFFER, undefined, undefined, true);
  }
  protected async addMeshWithColors(input: AddMeshInput) {
  