TMF stunt score calculation by blackq

===== Trackmania Forever stunt score calculation, reverse-engineered by blackq =====

This is a complete breakdown of stunt score calculation directly extracted from
the game. It aims at giving you a deeper understanding of stunt mode, clearing up
common misconceptions and ultimately making you a better stunter.

=== Technical stuff ===

Decompiled stunt score calculation method: https://pastebin.com/kN3wwrDW

Human-readable python script for calculating stunt scores: https://pastebin.com/Qr3wTq07

Example usage:

$ python -m calculate_stunt_score --help
$ python -m calculate_stunt_score --figure SPINNING_CHAOS --airtime 15000 --spin 15 --flip 0 --roll 0 --chain 34 --figure-received-points 100 --straight
564

=== How the actual stunt is determined ===

The stunt is purely determined by how much your car rotated around three axes: spin, flip and roll axis.

Some stunts have very similar axis weight distributions, so the game might give you inaccurate results
when your car bugs or your airtime is too low. Here are the similar stunts and how they are determined:

- Spin, Aerial and Alley
  - roll and flip amount close to zero
  - yields a spin if initial flip rotation is below a certain threshold
  - otherwise
    - yields an alley if rotation direction does not match the translation direction
    - otherwise yields an aerial if the opposite of the above happens
    - otherwise yields an alley as a fallback; from my observations, usually
      triggered when aiming for an aerial but turning in too much

- Backflip, Flip, Rodeo and Corkscrew
  - roll amount close to zero
  - yields a backflip if spin amount close to zero and flip amount is negative
  - otherwise yields a flip if spin amount close to zero and flip amount is positive
  - otherwise yields a rodeo if spin amount lower than flip amount
  - otherwise yields a corkscrew

- Roll, Twister and Spin Off
  - flip amount close to zero
  - TIP: holding the brake can prevent a flip amount; use for skillfully making twisters and spin offs!!!
  - yields a roll if spin amount close to zero
  - otherwise yields a twister if spin amount lower than roll amount
  - otherwise yields a spin off

- Free Style and Flip Flap
  - spin amount close to zero
  - yields a freestyle if flip amount lower than roll amount
  - otherwise yields a flipflap

- Flipping Mix, Spinning Chaos and Rolling Madness
  - fires when at least two of the axes have significant rotation
  - yields a rolling madness if roll axis is sufficiently high enough
  - otherwise
    - yields a flipping mix if spin amount lower than flip amount
    - otherwise yields a spinning chaos

- Basic Jump and Wrecks
  - if collision detection determined that part of your chassis hit an object, a wreck
    is generated; the wreck type depends on the rotation values
  - otherwise, if no other condition fired, defaults to a basic jump

=== How a straight and master stunt is determined ===

Your stunt is considered straight if your car is angled in the same way as it was at the beginning of the stunt.
The combined tolerance for this angle is roughly 15 degrees.

Your stunt is considered master if it is straight AND you pressed the exact same keys throughout the entire stunt.

Basic jumps cannot be master and the wrecks can neither be master nor straight.

=== How the base score is calculated ===

A common misconception among stunt players is that each stunt has a fixed "base point"
value. That, however, is not true. The base points are a combination of airtime and the
three axes rotations. Since SC, RM and FM use all three axes, they yield higher scores than
FF, FS, Rodeo and Corkscrew (which use two axes), which in turn yield higher scores than
BF, Flip, Spin, Aerial and Alley (which use only one axis).

The calculation is as follows, where "airtime" is the airtime in milliseconds divided
by 100 and "xxx_amount" defines the amount of 180 degree rotations:
> airtime + flip_amount * 15 + (spin_amount + roll_amount * 2) * 10;

Stunts that influence the base score:
- alley is hardcoded to have a bonus of 5 points. how generous ;)
- basic jumps and wrecks halve your points

What do we learn from this?
- the more airtime, the more points (in a linear fashion)
- the game favors flip and roll stunts
- fixed base points are an illusion!

=== How the straightness and master bonus is calculated ===

A multiplier times 1.5 for master and times 1.25 for straight stunts.

Try to master or at least straighten all your stunts.

=== How the chain bonus is calculated ===

- having any chain adds 0.2 to the multiplier.
- a chain greater than or equal two adds 0.15 to the multiplier
- a chain greater than or equal three adds 0.1 to the multiplier
- a chain greater than or equal four adds 0.05 to the multiplier
- a chain greater than or equal five adds 0.02 for each additional chain to the multiplier

Hold your chain, it's essential to getting high scores. And try to have at least a
single chain before going for any high-scoring stunts.

=== How the stunt repeat malus is calculated ===

The game stores a table of all points you ever received for all stunts. The higher
the table entry for any given stunt is, the bigger the penalty.
> total_points_received * 0.2 / 100.0

Repeating big stunts is bad.

=== How the final score is calculated ===

> base_points_with_penalty = round(base_points * (1.0 - malus))
> bonuses = chain_bonus + straightness_master_bonus
> final_multiplier = round(base_points_with_penalty * bonuses)

Hope this document was of use to you.