The concept of screen-wide color filtering has been brought up before, but I'm not sure of its feasibility. Essentially the main thing is that we'd have to find out 1) how to achieve such an effect in OpenGL and DirectX, and 2) if some objects (like parts of the HUD) are meant to be excluded from the filter, how to exclude them.

All this could be done by creating a list of filtered icons, but calculating those would be CPU-crunching on the client end, so I don't consider that doable. More doable would be some kind of "filter layer", where everything below the layer is filtered, but again only if DirectX or OpenGL supports that kind of thing. Modifying the color to make it darker or redder or what have you can be easily done through a screen-wide HUDE object that uses alpha transparency, but inversion or black-and-white vision are the sorts of things you would have to do via MapColors() if you did them on an icon, and I'm not sure what support exists for something like that.

There is apparently a GL extension function, glSeparableFilter2D(), that may be able to do this kind of thing, but I don't know if it'd be able to ignore upper layers or not. I'm not sure what DirectX's equivalent would be, if any.

Anyway, this feature may or may not be doable, but at the present time it would take more research to tell if it can be done or not. I'm pretty sure that if it is implemented, it'd only be available in the hardware-accelerated modes since software rendering would be a real dog.

Lummox JR