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Unit 8: 3-D in Computer Graphics
Phong Shading
The phong shading model was developed in 1973 by Bui-Tong Phong. The phong model consists of
three components namely,
1. Diffuse Relection: Here the intensity of light is independent of the direction to the viewer.
2. Specular: There is simulation of relective surfaces and specular highlights based on the viewer
direction.
3. Ambient: The light that is diffusely reflected from the surfaces results in an approximation of an
illumination.
The figure 8.7 displays the diffuse component. The light is falling from one-direction as the light is in
the normal to the surface, the shadow is bright and scattered equally.
Figure 8.7: Phong Shading
Source: http://people.rit.edu/pds2352/CGII/raytracer.htm
Phong model is more accurate when compared to other models. With incremental calculations the
components of the normal vector can be incremented from scan line to scan line, the interpolation along
edges can be done.
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