result = ...
Use premultiplied alpha
Use this tool to quickly visualize how the different blending modes work in OpenGL.
Graphics from www.interfacelift.com:
Splash by Richard MohlerThanks to Alex Huang for finding a bug in in the math for GL_FUNC_REVERSE_SUBTRACT.
Bisti Badlands by Ben DiAnna
Lazy Days II by boss019
Flamingos by Jestrella
Treetops - Michaux State Forest by Se7en
The Road To Bonneville by Chris F
Clouds Over Water by DerekProspero