I'm working on a transition effect where I have a texture and simply draw that as a pattern to my buffer. Here is a demo, use "e" to start the effect again. This looks fine but it won't work if the texture has pixels with alpha 0 < x < 1.
This is the texture I used in my demo ( zoomed ):
As you can see the edges are rough and full on opaque. If I do use a texture with softer edges the pixels with alpha will just smear the black away. How can I achieve the effect of pixels in my texture with an alpha of 0 < x 1 to only affect pixels with alpha 0 in my buffer?