message: BF: revertPreMultipliedAlpha needs to alter .rgb not .a.
diff: @@ -73,7 +73,7 @@ export namespace GLSLFragment {
  export const revertPreMultipliedAlpha = `
  vec4 revertPreMultipliedAlpha(vec4 rgba) {
  if (0.0 < rgba.a)
  - rgba.a /= rgba.a;
  + rgba.rgb /= rgba.a;
  return rgba;
  }`;
  