Banding artifact on open GL Render I'm currently working on an animation openGL project, and i have this "banding" artifacts on gradient induced by spotlights (see picture below)

I'm aware it seems to be because of 8bits precision calculation of the image, but is there any way to avoid this in Open GL ? 

I tried for now "Full Sample" option (i know it supposed to be non related, but who knows^^), i'm exporting 16bits png, i tried setting "dithering" parameter in the render panel but nothing works...

Any clue ? thanks a lot !
for those who have this problem, i found the origin of this problem !

It was induced in fact by environment lighting setting (world panel) and sun lights (i think hemi light will do the same, they seem to behave like sun light in open gl render.

So i solved the problem by getting rid of them and replacing it by area, point...

Happy blending !