Understanding displacement maps
Displacement maps are special texture maps used to create bumps on surfaces. While Normal maps are used to simulate bumpy surfaces, Displacement maps are used to actually reshape a surface. Figure 6.1 shows two surfaces. The left surface uses a Displacement map, while the right surface uses a Normal map.
Figure 6.1 – A comparison of a Displacement map with a Normal map
The two surfaces look almost identical from this perspective, but if you look at their geometry, you can see they are very different. Figure 6.2 shows the geometry of the two surfaces. The left surface has a higher poly count and is filled with bumps, while the right surface is a simple plane consisting of four edges.
Figure 6.2 – The geometry of a displaced surface and a surface with a Normal map
The Displacement map applied to the high-poly surface causes some of its polygons to move upwards, while others stay...