If you mean changing a specific colour in a sprite at drawing time, what you could do is:

1) render a rectangle the same size as the sprite which is all colour B at the location you want to render the sprite.

2) set the colour key for the sprite surface to colour A

3) draw the sprite on top of the rectangle which was drawn in 1)


You could also do that into a temporary surface if you''ll be doing it a lot.



--
Simon O''Connor
Creative Asylum Ltd
www.creative-asylum.com

You don''t need to use a sprite which is all of colour A though...
just use a Blt() to fill in one colour - it requires no storage.
If you use a temporary surface then you can change the key back afterwards e.g.:

1) you have *one* temporary surface in the application, created when it starts up. Call this lpDDSTemp.

2) use a Blt() colourfill to change all of lpDDSTemp to colour B

3) say the surface your sprite is on is called lpDDSSprite, set the colour key for lpDDSSprite to colour A

4) Blt() from lpDDSSprite to lpDDSTemp with colour keying enabled. This replaces colour A with colour B in lpDDSTemp

5) Blt() from lpDDSTemp to lpDDSSprite with colour keying disabled, this copies the sprites back.

6) set the colour key for lpDDSSprite to the proper/original colour key

7) lpDDSTemp is now unused and can be used for any other purpose - having a temp buffer around is always handy...


--
Simon O''Connor
Creative Asylum Ltd
www.creative-asylum.com