question

Phong illumination model 1 = ( N . 1) + 12 2 ( N . H ) N is the normal vector on the surface, L is the direction vector for light, and H is the half vector of Blinn. At this time, the triangle ABC was projected to a two-dimensional plane as shown in the following figure, and the normal vector, NA, NB, and NC at y A (2,6) NA(0, 0, 1) NB(12/2, 1/2, 1/2) scanline R (2, 3) B (1, 2) Nc(0, 0, 1) C (3, 1) The kind of light that is reflected in this triangle is called the direct light source and its directional vector is Le(-V2,1, 1) | viewing direction2 V= 1/2 1 1 2 (1) Get Blinn's half vector H. The color intensity, IR, of the Rasterized Point R(2,3) of this triangle. (2) Flat shading (3) Gouroud shading Use to get each one. However, in the case of flat shading, the intensity IA of vertex A is used and the R, G, and B values of IR are all the same, so you can get one of them