Seamlessly Layering Transparent Sprites In OpenGL ES

I am working on an Android app, based on the LibGDX framework (Though I don't think that should affect this problem too much), and I am having trouble finding a way to get the resu

Solution 1:

There might be a few other ways to do this: The most straight forward would be to attach a stencil buffer and draw circles to stencil first and then draw a full screen rect with desired color+alpha with the stencil, this should be much faster then some FBO with a separate texture.

Another thing might work is drawing those circles first with disabled blend and then your whole scene over it with inverted "blendFunc" but do note it might be impossible if other elements also need blending.

3rd instead of using stencil you could just use the alpha channel of your render buffer. Just use a color mask to draw only to alpha and draw the circles, then reenable RGB on color mask and draw the fullscreen rect using appropriate "blendFunc" also note here that if previous shapes have used blend you will need to clear the alpha to 1.0 before doing this (color mask to alpha only, disabled blend, draw full screen rect with color that has alpha set to 1.0)