On Thu, Dec 15, 2011 at 3:18 PM, Florian Berger <[email protected]>wrote:
> Hi, > > I am toying around with the above blitting flags. I am blitting a RGBA > sprite surrounded by transparent (i.e. alpha) pixels on a solid RGBA > surface (at least I suppose it is so, both are created from RGBA PNG > images). > > In my test setup, there is no difference between BLEND_ADD and > BLEND_RGBA_ADD. I hoped that the latter would honor alpha transparency, > and not add color values of transparent pixels, but this seems not to > be the case. :-/ > > Has anyone played with this? What is the difference between these two > supposed to be? > > Thanks! > Florian > Hi, I've never successfully gotten the blit flags to work *exactly* as I'd like. If you want perfect control, use the blending modes inherent in a graphics API like OpenGL. In PyGame, the most reliable way I've found to do this is to ensure that the surfaces actually do have alpha channels. Simply call .convert_alpha() on each surface after you make your window. This clears up most problems. Ian
