# Surface physics for ray tracing

## 1.Light and illumination

Introduces the physics mechanism why object show their color as you see.

Key words: photons, frequency, wavelength, spectra.

These physics principles is fundamental and each student with high school degree should know them.

## 2. Four mechanisms of light transport

- Perfect specular reflection
- perfect diffuse reflection
- perfect specular transmission

** total internal reflection*

** optics for transmission*

** Algebraic solution for T*

** Geometric solution for T* - perfect diffuse transmission

## 3. Practical reflection and transmission

Section 2 only introduces the simplified model. There are another 2 problems to solve: rough surface and color shifting.

**shading model** can solve that.

## 4. A Shading Model

Here we get a shading model which describe the reflected light as a combination of diffuse and specular components. The result is that we get the light that correctly bounced off complex surfaces, and very realistic shading.

## 5. Faster Shading

The Hall shading model give us a more simple description of shading model which origins from the model above.