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Re: [pygame] SDL vs. Pygame: Alpha Differences



Brian Fisher wrote:
On 12/24/06, Kamilche <kamilche@xxxxxxxxxxxx> wrote:
That special blit would still be nice, but it's not a showstopper,
because there's several methods around it, including Brian's and a
couple of others I've used.

If there was a special blit that might be able to help, I would think
it would be colorized blit - where as you blit the source color &
alpha is multiplied by a blending color & alpha, and that product is
what is used for blending to the dest. A colorized blit would probably
be significantly slower than a normal 32->24 blit, but would still be
much faster than making surface copies and modifiying them

(FYI, openGL can do colorized blits with absolutely no speed penalty
at all on the vast majority of hardware by setting the color of
vertices)


I'm confused... Aren't you (Kamilche) using OpenGL? If so then such a "colorized blit" definitely works. Simply update a quad's color, which is "multiplied" with it's texture. If you want to also change between textures, you could instead fade between several effects like sunset/rise or stars by blending layers with an alpha quad color. Not sure how large your sky texture is though, so perhaps this would burn too much video card ram.


-Jasper