Bump Mapping
Basic texture mapping paints on to a smooth surface
How do you make a surface look rough?
- Option 1: model the surface with many small polygons
- Option 2: perturb the normal vectors before the shading calculation
- the surface doesn’t actually change, but shading makes it look that way
- bump map fakes small displacements above or below the true surface
- can use texture-mapping for this
- texture image gives amount to perturb surface normal (see Foley for details)
- what kind of anomaly will this produce?
Sphere w/Diffuse Texture Map
Sphere w/Diffuse Texture + Bump Map