Finishing Lighting and Shading

• We have lighting model.
  • Out of sheer laziness look at Wikipedia's Implementation
  • The shader is passed
  • Here the vertex shader
    • Has a different transformation for the normals
    • Some transformations mess with the surface normals.
    • It also preserves the transformed coordinates.
    • Normals, and coordinates are interpreted in the pipeline
  • Then the fragment shader
    • Gets the interpolated surface normal and coordinates of the fragment
    • Implements the lighting equation.
• If this model is applied to the entire surface
  • Compute once using "the" surface normal
  • Apply the lighting model
  • Use this on the entire surface
  • You have flat shading.
• If the model is applied to each vertex
  • Then the colors interpolated across the polygon
  • This is the Gourand shading model (1971)
• If the surface normals are interpolated