| OCR Text |
Show 45 is Cp the reflection coefficient of the object at point P for certain a wavelength i is the incident angle . d is the environmental diffuse reflection coefficient W(i) is a function which gives the ratio of the and the incident is the angle s light as a reflected specular function of the incident light i angle between the direction of the reflected light and the line of sight is ·n a which power models The function W(i) and characteristics of materials and the a the the material. specular reflected light for each material, power Their n determination empirical method used in this process specular reflection sample of various described in Appendix the express for are a n In order to simplify the· model, and thereby the computation of the terms cos(i) and cos(s) of formula (4 5), it is assumed that: .. The 1. light source is located at infinity; that is, the light rays are parallel. 2. The eye is also removed to infinity. With these two considerations, the shading rewritten function in (4.5) can be as: Sp=Cp=] k*Np/INpl +d ] + W(i)*[ u*Rp/IRpl ]tn (4.6) ... where k the line and of u are sight, respectively, the unit vectors in the direction of the light and is the reflected light Np is the normal vector at P, and Rp |
