1. Lighting
   1. concepts
      1. surface
         1. smooth surface -> specular
         2. rough surface -> diffuse
      2. light principles
         1. Ambient
         2. Specular
         3. Diffuse
      3. user vectors
         1. to source (l) = light source - P
         2. to viewer (v) = eye - P
         3. perfect reflection (r) = 2(l . n)n - l
         4. normal vector (n)
   2. Phong model
      1. 9 coefficient for point source
      2. 9 coefficient for materials
      3. shininess coefficient (alpha)
      4. Formula
         1. Phong Model formula
      5. Phong Lighting Model
         1. glMaterialfv()
            1. glLightfv()
   3. Modified Phong model
      1. Subtopic 2
2. Shading
   1. Goround Shading
      1. find n of vertex
      2. colored vertex
      3. color interpolate
   2. Phong Shading
      1. find n of vertex
      2. interpolate n vector
      3. colored each point