Homogeneous light source: light of a single wavelength.

Contact shadows: a shadow at the points where objects touches each other.

Tricks and solutions on Shadow Map: Perspective Bias, Peter Panning, etc. [link]

Shadow Map Parameters Rollout: link

Tri-linear filtering: an extension of the bilinear texture filtering method, which also performs linear interpolation between mipmaps.

Environment mapping, or reflection mapping: an efficient image-based lighting technique for approximating the appearance of a reflective surface by means of a pre-computed texture image.