Normal maps?

Discuss programming topics for the various GPL'd game engine sources.
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SusanMDK
Posts: 601
Joined: Fri Aug 05, 2005 2:35 pm
Location: In The Sun

Normal maps?

Post by SusanMDK »

Not really programming it, but how's it programmed to DarkPlaces? Which colour is top, which left? Or does it matter?
zbang!
Sajt
Posts: 1215
Joined: Sat Oct 16, 2004 3:39 am

Post by Sajt »

It's standard. RGB=XYZ.
R=0 -> X=-1
R=0.5 (128) -> X = 0
R = 1 (255) ->X = 1

And they're tangent space.
+X=right, +Y=down, +Z=away from the surface. (note that it's also common to have +Y=up, but DarkPlaces has +Y=down).

To get plain Phong shading (as if you had no normal mapping), all the normals should point 'out', which is positive Z. The normal should be 0,0,1, therefore the colour should be 0.5,0.5,1 (aka 128,128,255). It's a light bluish-purple that you commonly see on normal maps.
F. A. Špork, an enlightened nobleman and a great patron of art, had a stately Baroque spa complex built on the banks of the River Labe.
SusanMDK
Posts: 601
Joined: Fri Aug 05, 2005 2:35 pm
Location: In The Sun

Post by SusanMDK »

Allright, then everything seems to be good with my normal map render settings and the maps... :)
zbang!
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