Quote Originally Posted by jasonf
It might be better to test if the RGBA.A > some Alpha Threshold, which could be set using the transparent colour, or a new property could be created.

If you just check for Alpha=255 then you'll only ever be able to collide with pixels with less than 100% transparency, but when you consider that a lot of the time, transparency is used for Anti-Aliasing, you'll end up with a lot of false collisions where it will look like things aren't really touching.
But if you set the Alpha Threshold to 128, then you'll collide with pixels which are less than 50% transparent but other pixels which are more transparent would not be used for collision, so anti aliased images would look like they're colliding properly.
Yes but how get RGBA.A from sdl surface?