Light

Vocabulary
With danish translations where appropriate
 * Incident:Indfaldende
 * Reflection:Change in light direction
 * Reflection types:
 * Specular reflection:Angle of incidence equals the angle of reflection
 * Diffuse reflection:Angle of reflection is random (due to irregularities in surface).
 * Lambertian reflection:A special case of perfect diffuse reflection where luminance of reflected light is equal regardless of angle of view
 * Irradiance:Power of incident light

Luminance
The amount of light that passes through or is emitted from a particular area, and falls within a given solid angle.

Luminance is defined by
 * $$L_v = \frac{d^2 F}{dA\,d{\Omega} \cos \theta}$$

where
 * $$L_v$$ is the luminance (candela/m2),
 * $$F$$ is the luminous flux or luminous power (lumen),
 * $$\theta$$ is the angle between the surface normal and the specified direction,
 * $$A$$ is the area of the source (m2), and
 * $$\Omega$$ is the solid angle (Steradian).

Local Illumination Model
A local illumination model considers only the surface we're rendering and the light sources. A local illumination model yields no shadows.