I need to draw multiple overlapping shapes with seperate draw array calls, all in the same colour (lets say white), which has a non 1.0 alpha value (for example a color of 1.0, 1.0, 1.0, 0.5). I need these to blend over the background "as one", i.e. i dont want to see the overlapping part at a different intensity, which is what would normally happen as the overlapping parts will be drawn twice and will blend together.
Is there anyway to do this? (I can only think of first rendering to a transparent texture, and then rendering that, but that seems a rather complex and expensive solution for this...). Maybe theres a blending mode I should use?
I would definitely be open to using a pixel shader if that is the "correct" way to do this, but until now ive never used shaders so if its the way to go I would appreciate some tips on the best way to do that.