Sparks and Screen Shake

Clip a tree at 30 m/s and the car spins 132°. It is a huge crash, and the game acts as if nothing happened. No spark, no dust, and the camera never blinks.

RoadFX draws every crash. It also gives RoadCamera's shake its first hits, so a big one lands in your hands.

Trauma

A shake needs a size. RoadCamera keeps one number for it, trauma, from 0 to 1. Every hit adds to it, and time drains it at 1.6 a second. The camera moves by trauma squared, times shakeMax, which is 1.4 m:

shake size = trauma² × 1.4 m

Squaring keeps small numbers small and lets big ones through:

trauma   trauma²   shake size
0.1      0.01      0.014 m
0.29     0.08      0.11 m     a 10 m/s tap on a tree
0.8      0.64      0.90 m     a 28 m/s crash

On screen the tap moves the view 1.1 px and is gone in 0.17 s. The crash moves it 15 px and shakes for half a second.