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670 26. Computer Graphics in Games
Figure 26.13. Rendering of the mesh with normal map and final color texture (from Fig-
ure 26.12) applied.
Image courtesy Keith Bruns.
(See also Plate XL.)
If this additional detail were to be represented with actual geometry, millions
of triangles would be needed. Instead, the detail is commonly “baked” into a nor-
mal map which is applied onto the original, coarse mesh, as shown in Figures 26.8
and 26.9.
Besides normal maps, multiple textures containing surface properties such as
diffuse color, specular color, and smoothness (specular power) are also created.
These are either painted directly on the surface in the detail modeling application,
or in a two-dimensional application such as Photoshop. All of these texture maps
use the surface parameterization defined in the initial modeling phase. When the
texture is painted in a two-dimensional painting application, the artist must fre-
quently switch between the painting application and some other application which
can show a three-dimensional rendering of the object with the texture applied.
This iterative process is illustrated in Figures 26.10, 26.11, 26.12, and 26.13.
Shading
Shaders are typically applied in the same application used for initial modeling. In
this process, a shader (from the set of shaders defined for that game) is applied
to the mesh. The various textures resulting from the detail modeling stage are
applied as inputs to this shader, using the surface parameterization defined during
initial modeling. Various other shader inputs are set via visual experimentation
(“tweaking”); see Figure 26.14.