Linearly interpolates between a and b by weight using the formula a + (b-a) * weight.

If weight is 0.5, lerp will return the value half-way between a and b. When a = 10 and b = 20, lerp(a, b, 0.5) will return 15. You can think of weight as the percentage of interpolation from a to b, 0.0 being 0% and 1.0 being 100%.

lerp can be used for many things. You could rotate a sprite by a weight with angle = lerp(0, 360, weight). You could even scale an enemy's attack value based on the level you're playing:

If you're on level 0, attack will be 10, if you're on level 10, attack will be 50. If you're on level 5, the result of current_level/MAX_LEVEL will be 0.5 which represents 50%, therefore attack will be 30, which is the midpoint of 10 and 50.

Raises a ValueError if weight is outside the range of [0, 1].

New in pygame 2.1.3.