image processing basics

[Redrobes]

Dont use SetPixel or even SetPixelV as they are amazingly slow. You could use Direct draw but that might be a pain and if your still going to use that with calls to set pixel APIs then it will be even slower than GDI.

The best bet for you right now with Windows only is to use the CreateDIBSection function and look into the parameter that is the ppvbits. That gets you a memory pointer to the bitmap bits so you can update them without going through the hassle of SetPixel. I.e. its much much faster. There are faster methods but not very likely faster and easier.

Once you have a bitmap modified to your users liking then during the WM_PAINT you can blit the bitmap direct to the paint DC with one call of a StretchDIBits and not faff about with per pixel calls. It will easily be more than 100x faster.

From a compatibility point of view OpenGL is more cross platform than Direct Draw. If your interested in 3D height terrain viewing then you can look at my free 3D terrain viewer.
http://www.viewing.ltd.uk/viewingdal...gonsFlight.zip
Just put a "height.bmp" file into the same folder and run it up. The height bitmap is greyscale. If you tried my instant islands then it exports that same file so put the two together. Run II then export the terrain you like then run DF.

Oh and on the blur I am with Waldronate, I would use an FFT or a DFT and then mult in a gaussian kernel and then go back using another FFT/DFT in reverse. If you were blurring just a couple of pixels blur then a convolution is easier to code and probably faster on a normal CPU. The larger the blur, the more likely the FFT will win in performance.