ok so I have a directdraw surface and I want to tint it as I would by changing the tone of a viewpoint. no idea how to do this though.
EDIT: ok so I figured out that the effect is akin to the photoshop screen blending mode.
Quote
Screen
Looks at each channel's color information and multiplies the inverse of the blend and base colors. The result color is always a lighter color. Screening with black leaves the color unchanged. Screening with white produces white. The effect is similar to projecting multiple photographic slides on top of each other.
but how would I create this effect?