Dolphin, the GameCube and Wii emulator - Forums

Bump mapping just required more fillrate (adding detail without adding polygons was the tagline). Hollywood's ~1 gigapixel is 4x than Matrox's G400 that was the poster child for EMBM.

Bump mapping or normal mapping shouldn't be hard to program, but I don't see the usage. I agree, it may look awful, but I doubt that there will ever be a bump/normal mapping set for a complete game. Custom texture are mostly used for HUD, but rarely for the game content. Bump mapping is only needed for the game content, so it should be done for a complete game. This will be _much_ more work than to program it ...

(06-24-2013, 09:41 AM)MaJoR Wrote: [ -> ]Normal maps are a different story however. Their use of multiple channels makes them impractical to paint by hand.

So that's why all the ones I've got from Skyrim are all blue and transparent! But I'm still not sure what the extra information is supposed to encode. It doesn't seem to do anything more than a bump map (as you've described it) does, and I know that I seem to get identical results from using GIMP's normal map plugin to make a grayscale map into a blue and transparent map, and just using a blue and transparent normal map from the outset. I shall return after more research into the differences between these techniques.

Normal maps use RGB to indicate height from all three angles, allowing for three dimensional space to be approximated in the texture. Red is X axis, Green is Y axis, Blue is Z axis. Bump maps, which I have been trained by coders to call "Height maps", just have the Z axis. The additional information allows for much higher quality mapping, and the ability to bake complex geometry onto a lower polygon version of the model.

Quote: I seem to get identical results from using GIMP's normal map plugin to make a grayscale map into a blue and transparent map

That's the height map conversion I talked about earlier. Basically a program uses the height map to guess what the other values would be and makes a normal map based on said guess. It does work in a pinch, but it does get inferior results compared to the real thing. It can work well for basic stuff though.

I'm still not sure why that would allow for greater detail. They'd both be mapped onto a plain, in which case, only the z data would make any difference, surely? Also, blender calls both techniques normal mapping.

I tried a dozen times to explain it properly and kept hating it, so I looked around and found something. Here, read this.

http://www.game-artist.net/forums/support-tech-discussion/7756-bump-maps-vs-normal-maps.html


As for Blender, that's simply because bump maps are ancient at this point, and Blender expects normal maps. Older programs like Max still call them bump maps, and require hoops to jump through to use normal maps. It's annoying; Blender is better. As the Blender wiki states:

*When using a Bump map, map the texture to Normal and enable No RGB.
*When using a Normal map, map the texture to Normal.

Blender only has a slot for normal maps, since that is expected. However, you can use a height map (called intensity map in Blender) by turning on No RGB. I'll admit it's a little confusing, but they did it to keep the interface from being cluttered with an option that is irrelevant. As the wiki says at length, using no RGB and a greyscale map does not affect normals.

I think that game engines are being stupid if they can't work out a normal map from a height map. At least I now understand what the other channels encode for.

Quote:I think that game engines are being stupid if they can't work out a normal map from a height map.

Less information is less information. Simple stuff (like stuff on a flat surface) can be converted by the Nvidia Tools package (used it myself a few times), but the majority of normal map use cases are just too complex for this. This is why normal maps have totally replaced bump maps, they do the same thing as bump maps, but by having more information they are able to do way more than what bump maps can do, and do everything in higher quality. So don't say it's stupid, normal maps contain a TON of information, and for the majority of uses a height map simply won't cut it even after conversion.

After much thought, I've thought of a situation where you couldn't reliably compute a normal map from a bump map. Congratulations, you have emerged victorious.

Also, it would have helped if you had put the link to the blender wiki and the good explanation in its own post, instead of editing it into an existing one. That way I'd have seen it.

Huzzah! And before the mods yelled at us for being off topic too! All right everyone, back to our regularly scheduled topic: bump maps being applied by Dolphin to GC/Wii games?