Alpha related features

With regards adding an alpha channel to an image, these would make it easier

  1. Allow drag and drop from the Diffuse Slot to the Opacity Slot
  2. By default, have A for Alpha selected ( and not R for Red channel ) in the OpacityMapChannel.

Maybe have Alpha selected by default, rather than None, if the Opacity Map is ignored for optimisation if it doesn’t have an image assigned.

Also, would be cool to have a button or icon in the Diffuse area ( eg Set Up Opacity From Alpha ) that automatically sets the material to use the alpha channel of the diffuse image for transparency ( if it has an alpha channel ), to help speed up this process.