In my current task, i need to render a texture into a render buffer, in order to work on it (apply special filters) there. The result is then considered a "new texture", which is later displayed.

This works fine, except when the texture contains some transparent/semi-transparent parts.

My current guess it that, within the render buffer, the texture is "merged" with a kind of "grey background". In this case, it obviously impacts the R,G,B color components of transparent pixels. I've yet to find a way around this.

Even manually assigning alpha after the rendering process doesn't save the day for semi-transparent pixels, which RGB are "tainted" by the grey background.