anchor.diff:  
   class CubeTexture extends Texture {
     CubeTexture(ChronosGL cgl, String url, List images)
  -      : super(cgl, GL_TEXTURE_CUBE_MAP, url, new TextureProperties()) {
  +      : super(cgl, GL_TEXTURE_CUBE_MAP, url,
  +            new TextureProperties()..clamp = true) {
       assert(images.length == _kCubeModifier.length);
       properties.InstallEarly(_cgl, _textureType);
   
  
positive.code:   Texture(this._cgl, this._textureType, this._url, this.properties)
        : _texture = _cgl.createTexture();
  
  
    void CopyFromFramebuffer2D(int x, int y, int w, int h) {
       _cgl.bindTexture(_textureType, _texture);
       _cgl.copyTexImage2D(_textureType, 0, GL_RGBA, x, y, w, h);
      Install();
    }
  
    void Install() {
        _cgl.bindTexture(_textureType, _texture);
        properties.InstallLate(_cgl, _textureType);
        int err = _cgl.getError();
        assert(err == GL_NO_ERROR);
    }
  
  
    int GetTextureType() => _textureType;
  
  
negative.code:   ..clamp = true
    ..mipmap = false
    ..shadow = true;
  //..SetFilterNearest();
  
  bool IsCubeChildTextureType(int t) {
    switch (t) {
  