method resize

Source

void resize(int width, int height) {

  if (_source is VideoElement) {

    throw new StateError("RenderTexture is not resizeable.");

  } else if (_width == width && _height == height) {

    // there is no need to resize the texture

  } else if (_source == null) {

    _width = width;
    _height = height;

    if (_renderContext == null || _texture == null) return;
    if (_renderContext.contextIdentifier != contextIdentifier) return;

    var target = gl.TEXTURE_2D;
    var rgba = gl.RGBA;
    var type = gl.UNSIGNED_BYTE;

    _renderContext.activateRenderTexture(this);
    _renderingContext.texImage2D(target, 0, rgba, _width, _height, 0, rgba, type, null);

  } else {

    _width = width;
    _height = height;
    _canvas = _source = new CanvasElement(width: _width, height: _height);
  }
}