I am using openGL and programming on an iPhone.
I am rendering a glowing 'beam' on top of my game scene. I am using a few textures with additive blending to make the glow effect. If the beam is rendered on a pure black background, the beam will look exactly how I want it, however, when the beam is rendered on my ever changing game, it blends with the colors behind it.
Currently, this is my only idea:
1) Render the beam to a texture and draw the texture on the background using normal blending.
Problems - The texture will always be opaque (black is my glClear color). I do not yet know how to remove all of the black from the texture I rendered to.
Any suggestions?