zenno/doc/frbm: chart and calcs for section speed

zenno/src/lib/race.ts

@@ -1,6 +1,7 @@
 // Umamusume race mechanics adapted from KuromiAK's doc:
 // https://docs.google.com/document/d/15VzW9W2tXBBTibBRbZ8IVpW6HaMX8H0RP03kq6Az7Xg/edit?usp=sharing
 
+import * as math from "mathjs";
 import { binomPMF } from "./prob";
 
 /**
@@ -43,6 +44,17 @@ export enum RunningStyle {
 	GreatEscape,
 }
 
+/**
+ * Running styles with their proper names, for easy iterating.
+ */
+export const RUNNING_STYLES = [
+	['Front Runner', RunningStyle.FrontRunner],
+	['Pace Chaser', RunningStyle.PaceChaser],
+	['Late Surger', RunningStyle.LateSurger],
+	['End Closer', RunningStyle.EndCloser],
+	['Great Escape', RunningStyle.GreatEscape],
+] as const;
+
 /**
  * Aptitude or proficiency levels.
  */
@@ -95,6 +107,40 @@ const speedStrategyPhaseCoeff = [
 
 const distanceProficiencyMod = [0.1, 0.2, 0.4, 0.6, 0.8, 0.9, 1.0, 1.05] as const;
 
+/**
+ * Calculate the range of section speed values for a horse in early or mid race.
+ * @param raceLen Length of the race in meters
+ * @param baseWit Base wit, after mood but before other modifiers
+ * @param witStat Final wit stat, including strategy proficiency and skills
+ * @param style Horse's running style
+ * @param phase Phase of the current section
+ */
+export function sectionSpeed(raceLen: number, baseWit: number, witStat: number, style: RunningStyle, phase: Exclude<Phase, Phase.LateRace>): [number, number];
+/**
+ * Calculate the range of section speed values for a horse not spurting during late race.
+ * @param raceLen Length of the race in meters
+ * @param speedStat Final speed stat
+ * @param baseWit Base wit, after mood but before other modifiers
+ * @param witStat Final wit stat, including strategy proficiency and skills
+ * @param style Horse's running style
+ * @param distance Hores's distance proficiency aptitude
+ * @param phase Phase.LateRace
+ */
+export function sectionSpeed(raceLen: number, speedStat: number, baseWit: number, witStat: number, style: RunningStyle, distance: AptitudeLevel, phase: Phase.LateRace): [number, number];
+export function sectionSpeed(raceLen: number, speedStatOrBaseWit: number, baseWitOrWitStat: number, witStatOrStyle: number | RunningStyle, styleOrPhase: RunningStyle | Phase, distance?: AptitudeLevel, lateRace?: Phase.LateRace): [number, number] {
+	const speedStat = lateRace !== undefined ? speedStatOrBaseWit : 0;
+	const baseWit = lateRace !== undefined ? baseWitOrWitStat : speedStatOrBaseWit;
+	const witStat = lateRace !== undefined ? witStatOrStyle : baseWitOrWitStat;
+	const style = lateRace !== undefined ? styleOrPhase as RunningStyle : witStatOrStyle as RunningStyle;
+	const phase = lateRace !== undefined ? lateRace : styleOrPhase as Phase;
+	const base = baseSpeed(raceLen);
+	const baseTarget = base * speedStrategyPhaseCoeff[style][phase];
+	const late = phase === Phase.LateRace ? (math.sqrt(500 * speedStat) as number) * distanceProficiencyMod[distance ?? AptitudeLevel.A] * 0.002 : 0;
+	const u = witStat / 550000 * math.log10(baseWit * 0.1);
+	const l = u - 0.0065;
+	return [baseTarget + late + base*l, baseTarget + late + base*u];
+}
+
 /**
  * Calculate an Uma's last spurt target speed.
  * @param speedStat Adjusted speed stat
@@ -326,3 +372,21 @@ export function speedGain(speedBonus: number, dur: number, accel: number | null,
 export function downhillAccelEnterChance(witStat: number): number {
 	return witStat * 0.0004;
 }
+
+/**
+ * Calculate the chance for a front runner to enter speed-up or overtake mode when eligible.
+ * @param witStat Final wit stat, including style aptitude modifier
+ * @returns Probability each eligible tick to enter speed-up or overtake mode
+ */
+export function frontModeEnterChance(witStat: number): number {
+	return 0.2 * math.log10(witStat) - 0.2;
+}
+
+/**
+ * Calculate the chance for a non-front runner to enter pace-up mode when eligible.
+ * @param witStat Final wit stat, including style aptitude modifier
+ * @returns Probability each eligible tick to enter pace-up mode
+ */
+export function paceUpEnterChance(witStat: number): number {
+	return 0.15 * math.log10(witStat) - 0.15;
+}