apply tidal lock to telluric and gas planets

BarthPaleologue · Nov 3, 2024 · 2af3033 · 2af3033
1 parent 9db39c7
commit 2af3033
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Showing 2 changed files with 47 additions and 24 deletions.
diff --git a/src/ts/planets/gasPlanet/gasPlanetModel.ts b/src/ts/planets/gasPlanet/gasPlanetModel.ts
@@ -22,19 +22,21 @@ import { Axis } from "@babylonjs/core/Maths/math.axis";
 import { clamp } from "../../utils/math";
 import { getOrbitalPeriod, getPeriapsis, Orbit } from "../../orbit/orbit";
 import { PlanetaryMassObjectPhysicsInfo } from "../../architecture/physicsInfo";
-import { CelestialBodyModel } from "../../architecture/celestialBody";
 import { newSeededRingsModel } from "../../rings/ringsModel";
 import { GenerationSteps } from "../../utils/generationSteps";
 
 import { getRngFromSeed } from "../../utils/getRngFromSeed";
 import { OrbitalObjectType } from "../../architecture/orbitalObject";
 import { PlanetModel } from "../../architecture/planet";
+import { StellarObjectModel } from "../../architecture/stellarObject";
+import { getCurrentUniverseYear, getTidalLockingTimescale } from "../../utils/physics";
+import { Lerp } from "@babylonjs/core/Maths/math.scalar.functions";
 
 export type GasPlanetModel = PlanetModel & {
     readonly type: OrbitalObjectType.GAS_PLANET;
 };
 
-export function newSeededGasPlanetModel(seed: number, name: string, parentBodies: CelestialBodyModel[]): GasPlanetModel {
+export function newSeededGasPlanetModel(seed: number, name: string, parentBodies: StellarObjectModel[]): GasPlanetModel {
     const rng = getRngFromSeed(seed);
 
     const radius = randRangeInt(Settings.EARTH_RADIUS * 4, Settings.EARTH_RADIUS * 20, rng, GenerationSteps.RADIUS);
@@ -57,11 +59,22 @@ export function newSeededGasPlanetModel(seed: number, name: string, parentBodies
         orientation: Quaternion.RotationAxis(Axis.X, (rng(GenerationSteps.ORBIT + 20 - 0.5) * 0.2))
     };
 
+    //FIXME: when Settings.Earth radius gets to 1:1 scale, change this value by a variable in settings
+    const mass =Settings.JUPITER_MASS * (radius / 69_911e3) ** 3;
+
+    const tidalLockingTimescale = getTidalLockingTimescale(parentMassSum, mass, orbitRadius, radius, 0);
+
+    const parentMaxBirthYear = parentBodies.reduce((max, body) => Math.max(max, body.birthYear), 0);
+    const currentAge = getCurrentUniverseYear() - parentMaxBirthYear;
+
+    const tidalLockingFactor = Math.min(1, currentAge / tidalLockingTimescale);
+
+    const siderealDayDuration = Lerp(60 * 60 * 24, orbit.period, tidalLockingFactor);
+
     const physicalProperties: PlanetaryMassObjectPhysicsInfo = {
-        //FIXME: when Settings.Earth radius gets to 1:1 scale, change this value by a variable in settings
-        mass: Settings.JUPITER_MASS * (radius / 69_911e3) ** 3,
+        mass: mass,
         axialTilt: Quaternion.RotationAxis(Axis.X, normalRandom(0, 0.4, rng, GenerationSteps.AXIAL_TILT)),
-        siderealDayDuration: (24 * 60 * 60) / 10,
+        siderealDayDuration: siderealDayDuration,
         minTemperature: -180,
         maxTemperature: 200,
         pressure: 1

diff --git a/src/ts/planets/telluricPlanet/telluricPlanetModel.ts b/src/ts/planets/telluricPlanet/telluricPlanetModel.ts
@@ -17,35 +17,59 @@
 
 import { PlanetModel } from "../../architecture/planet";
 import { OrbitalObjectType } from "../../architecture/orbitalObject";
-import { CelestialBodyModel } from "../../architecture/celestialBody";
 import { getRngFromSeed } from "../../utils/getRngFromSeed";
 import { normalRandom, randRangeInt, uniformRandBool } from "extended-random";
 import { GenerationSteps } from "../../utils/generationSteps";
 import { Settings } from "../../settings";
 import { TelluricPlanetaryMassObjectPhysicsInfo } from "../../architecture/physicsInfo";
-import { hasLiquidWater } from "../../utils/physics";
+import { getCurrentUniverseYear, getTidalLockingTimescale, hasLiquidWater } from "../../utils/physics";
 import { CloudsModel, newCloudsModel } from "../../clouds/cloudsModel";
-import { Vector3 } from "@babylonjs/core/Maths/math.vector";
 import { Quaternion } from "@babylonjs/core/Maths/math";
 import { Axis } from "@babylonjs/core/Maths/math.axis";
 import { getOrbitalPeriod, Orbit } from "../../orbit/orbit";
 import { clamp } from "terrain-generation";
 import { newSeededRingsModel, RingsModel } from "../../rings/ringsModel";
 import { TelluricPlanetaryMassObjectModel } from "./telluricPlanetaryMassObjectModel";
+import { StellarObjectModel } from "../../architecture/stellarObject";
+import { Lerp } from "@babylonjs/core/Maths/math.scalar.functions";
 
 export type TelluricPlanetModel = PlanetModel &
     TelluricPlanetaryMassObjectModel & {
         readonly type: OrbitalObjectType.TELLURIC_PLANET;
     };
 
-export function newSeededTelluricPlanetModel(seed: number, name: string, parentBodies: CelestialBodyModel[]): TelluricPlanetModel {
+export function newSeededTelluricPlanetModel(seed: number, name: string, parentBodies: StellarObjectModel[]): TelluricPlanetModel {
     const rng = getRngFromSeed(seed);
 
     const radius = Math.max(0.3, normalRandom(1.0, 0.1, rng, GenerationSteps.RADIUS)) * Settings.EARTH_RADIUS;
 
+    const parentMaxBirthYear = parentBodies.reduce((max, body) => Math.max(max, body.birthYear), 0);
+
+    const parentMaxRadius = parentBodies.reduce((max, body) => Math.max(max, body.radius), 0);
+    // Todo: do not hardcode
+    const orbitRadius = 2e9 + rng(GenerationSteps.ORBIT) * 15e9 + parentMaxRadius * 1.5;
+
+    const orbitalP = 2; //clamp(normalRandom(2.0, 0.3, this.rng, GenerationSteps.Orbit + 80), 0.7, 3.0);
+
+    const parentMassSum = parentBodies.reduce((sum, body) => sum + body.physics.mass, 0);
+    const orbit: Orbit = {
+        radius: orbitRadius,
+        p: orbitalP,
+        period: getOrbitalPeriod(orbitRadius, parentMassSum),
+        orientation: Quaternion.RotationAxis(Axis.X, (rng(GenerationSteps.ORBIT + 20) - 0.5) * 0.2)
+    };
+
     //TODO: make mass dependent on more physical properties like density
     const mass = Settings.EARTH_MASS * (radius / 6_371e3) ** 3;
 
+    const tidalLockingTimescale = getTidalLockingTimescale(parentMassSum, mass, orbitRadius, radius, 0);
+
+    const currentAge = getCurrentUniverseYear() - parentMaxBirthYear;
+
+    const tidalLockingFactor = Math.min(1, currentAge / tidalLockingTimescale);
+
+    const siderealDayDuration = Lerp(60 * 60 * 24, orbit.period, tidalLockingFactor);
+
     let pressure = Math.max(normalRandom(0.9, 0.2, rng, GenerationSteps.PRESSURE), 0);
     if (radius <= 0.3 * Settings.EARTH_RADIUS) pressure = 0;
 
@@ -57,7 +81,7 @@ export function newSeededTelluricPlanetModel(seed: number, name: string, parentB
     const physicalProperties: TelluricPlanetaryMassObjectPhysicsInfo = {
         mass: mass,
         axialTilt: Quaternion.RotationAxis(Axis.X, normalRandom(0, 0.2, rng, GenerationSteps.AXIAL_TILT)),
-        siderealDayDuration: (60 * 60 * 24) / 10,
+        siderealDayDuration: siderealDayDuration,
         minTemperature: minTemperature,
         maxTemperature: maxTemperature,
         pressure: pressure,
@@ -75,20 +99,6 @@ export function newSeededTelluricPlanetModel(seed: number, name: string, parentB
         clouds = newCloudsModel(radius + physicalProperties.oceanLevel, Settings.CLOUD_LAYER_HEIGHT, physicalProperties.waterAmount, physicalProperties.pressure);
     }
 
-    const parentMaxRadius = parentBodies.reduce((max, body) => Math.max(max, body.radius), 0);
-    // Todo: do not hardcode
-    const orbitRadius = 2e9 + rng(GenerationSteps.ORBIT) * 15e9 + parentMaxRadius * 1.5;
-
-    const orbitalP = 2; //clamp(normalRandom(2.0, 0.3, this.rng, GenerationSteps.Orbit + 80), 0.7, 3.0);
-
-    const parentMassSum = parentBodies.reduce((sum, body) => sum + body.physics.mass, 0);
-    const orbit: Orbit = {
-        radius: orbitRadius,
-        p: orbitalP,
-        period: getOrbitalPeriod(orbitRadius, parentMassSum),
-        orientation: Quaternion.RotationAxis(Axis.X, (rng(GenerationSteps.ORBIT + 20) - 0.5) * 0.2)
-    };
-
     const terrainSettings = {
         continents_frequency: radius / Settings.EARTH_RADIUS,
         continents_fragmentation: clamp(normalRandom(0.65, 0.03, rng, GenerationSteps.TERRAIN), 0, 0.95),