I am creating a 2d mapeditor, I wish to be able to load bitmaps of maps and place them on the terrain so the user can use the bitmap as a tracer if you know what I mean.
I have done this, what I really want to do is make this bitmap/texture transparent via a slider control so the user can bring it in and out to their desired transparency.
How do I draw a texture then edit it’s alpha value then redraw it again in the best way?