I've been searching the internet for some time to find a simple normalmap generator and mostly found commercial stuff like CrazyBump or bloated programs that do a lot more than is needed for me. Another possibility is a free Photoshop or Fimp plugin. As I don't own Photoshop and am not much of a friend of Gimp I decided to write a generator myself. Actually it's a rip from a bigger editor I'm working on so don't expect too much.
Do you combine the normalmaps of three different blurr stages? It would probably be nice to have a little more freedom, but I guess the results are already better than those, still too many people are working with. What about maybe some batch functionality? The results may aren´t perfect for each texture then, but I am lazy and have quite a few textures without normalmaps
The map is scaled to 1/4 and 1/8 and rescaled again so it's actually bilinear filtering only. Batch functionality should be possible. Maybe I'll implement it but rotating the preview cube is more important right now.
A little bug: The "generate" process did not stop (the progress bar was complete) and the generate window did not disappear after I clicked the button to create the normal map a second time with a higher "big detail" value.
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual
Do you use the CPU or the GPU? I started dev such an editor using pp effects wich was indeed quite fast, but then I decided to wait for the engine feature wich allows you to modify a bitmap through a shader directly (instead of the rendering only) since using ppEffects is not so handy