How do you correctly render a particle effect, which have particles that are blended additively, onto an image background?
The particles are also blended additively to the background, how can avoid that? (i.e blend them additively to each other but not to the background as well)
Actually, I have additional constraints:
I'm working on a 2D game for mobile devices (OpenGL ES 2.0) that is rendered using 8 layers as follows:
1. Background #1 (parallax scrolling)
2. Background #2 (parallax scrolling)
3. Background #3 (parallax scrolling)
4. Particle Effects Layer #1
5. Game Objects
6. Particle Effects Layer #2
8. Particle Effects Layer #3
If FBO is the only way to go to solve the blending problem, I'd have to create 8 textures that have the screen dimensions, and render each layer separately to the FBO. Then rendering the 8 textures to the window frame buffer which is too heavy on memory. I can alternatively use a single texture but that'll require 16 FBO switches...