Textures

A set of coordinates [u, v] within the range 0-1 on each axis, mapped to a given texture, which say what part of the texture a fragment should render.

A texture element to be drawn onto a fragment

A square of an image in a power of two size

The blending of texels, in the case of an image being too close to the screen.
E.g., texel coordinate 13.2, we interpolate the value between 13 and 14 by a factor of 0.2, blending them together.
For best results, we do this 4 times in a 2*2 and interpolate in all directions.

Clamp: Forced within [0, 1], doesn't repeat
Repeat: 1.1 rolled over to 0.1
Mirror: 1.1 reverses to 0.9

When a primitive is so far in the distance it only takes up a small texture, smaller than the texture it samples from.

An approximate chain of textures, each half in size from the previous and with less detail, each used at different LODs (level of detail) at different distances from the camera.

Clear lines where LODs cross

The fix to hard MIP levels, sampling adjacent MIP levels and interpolating by the fraction between them.

Determines how opaque an object is

Final Colour = (source colour * source factor) + (dest colour * dest factor)

Source = new, dest = what is there
Factor = alpha

Uses linear interpolation between these

Need to go from furthest to first (back buffer only stores RGB), which is very inefficient for opaque objects.
Only done for semi-transparent objects.