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Adaptive Physics Time Step #989

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merged 9 commits into from
Jun 29, 2024
Merged

Adaptive Physics Time Step #989

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2a12a96
Need to adjust joints
HunterBarclay Jun 21, 2024
cf85e15
Still not quite as stable as I'd like
HunterBarclay Jun 23, 2024
f6618f6
Fixed prettier formatting, updated workflow
HunterBarclay Jun 26, 2024
49a03d9
Fixed little errors with prettier
HunterBarclay Jun 26, 2024
c859ffc
Merge branch 'dev' into barclah/1716/physics-time-step
HunterBarclay Jun 27, 2024
c4d2e34
Format
HunterBarclay Jun 27, 2024
1f843d7
Merge branch 'dev' into barclah/1716/physics-time-step
HunterBarclay Jun 27, 2024
bc8680f
Actually so much better
HunterBarclay Jun 28, 2024
d18dc59
Merge branch 'dev' into barclah/1716/physics-time-step
HunterBarclay Jun 28, 2024
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25 changes: 21 additions & 4 deletions fission/src/systems/physics/PhysicsSystem.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,16 @@ const RobotLayers: number[] = [
// Please update this accordingly.
const COUNT_OBJECT_LAYERS = 10

export const SIMULATION_PERIOD = 1.0 / 120.0
const STANDARD_SUB_STEPS = 3
export const STANDARD_SIMULATION_PERIOD = 1.0 / 60.0
const MIN_SIMULATION_PERIOD = 1.0 / 120.0
const MAX_SIMULATION_PERIOD = 1.0 / 10.0
const STANDARD_SUB_STEPS = 2
const TIMESTEP_ADJUSTMENT = 0.0001

let lastDeltaT = STANDARD_SIMULATION_PERIOD
export function GetLastDeltaT(): number {
return lastDeltaT
}

/**
* The PhysicsSystem handles all Jolt Phyiscs interactions within Synthesis.
Expand Down Expand Up @@ -701,8 +709,17 @@ class PhysicsSystem extends WorldSystem {
return this._joltPhysSystem.GetBodyLockInterface().TryGetBody(bodyId)
}

public Update(_: number): void {
this._joltInterface.Step(SIMULATION_PERIOD, STANDARD_SUB_STEPS)
public Update(deltaT: number): void {
const diffDeltaT = deltaT - lastDeltaT
lastDeltaT = lastDeltaT + Math.min(TIMESTEP_ADJUSTMENT, Math.max(-TIMESTEP_ADJUSTMENT, diffDeltaT))

lastDeltaT = Math.min(MAX_SIMULATION_PERIOD, Math.max(MIN_SIMULATION_PERIOD, lastDeltaT))

const substeps = Math.max(1, Math.floor((STANDARD_SIMULATION_PERIOD / lastDeltaT) * STANDARD_SUB_STEPS))

console.log(`DeltaT: ${lastDeltaT.toFixed(5)}, Substeps: ${substeps}`)

this._joltInterface.Step(lastDeltaT, substeps)
}

public Destroy(): void {
Expand Down
4 changes: 2 additions & 2 deletions fission/src/systems/simulation/driver/HingeDriver.ts
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
import Jolt from "@barclah/jolt-physics"
import Driver from "./Driver"
import { SIMULATION_PERIOD } from "@/systems/physics/PhysicsSystem"
import { GetLastDeltaT } from "@/systems/physics/PhysicsSystem"
import JOLT from "@/util/loading/JoltSyncLoader"

class HingeDriver extends Driver {
Expand Down Expand Up @@ -60,7 +60,7 @@ class HingeDriver extends Driver {
const springSettings = motorSettings.mSpringSettings

// These values were selected based on the suggestions of the documentation for stiff control.
springSettings.mFrequency = 20 * (1.0 / SIMULATION_PERIOD)
springSettings.mFrequency = 20 * (1.0 / GetLastDeltaT())
springSettings.mDamping = 0.995

motorSettings.mSpringSettings = springSettings
Expand Down
4 changes: 2 additions & 2 deletions fission/src/systems/simulation/driver/SliderDriver.ts
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
import Jolt from "@barclah/jolt-physics"
import Driver from "./Driver"
import { SIMULATION_PERIOD } from "@/systems/physics/PhysicsSystem"
import { GetLastDeltaT } from "@/systems/physics/PhysicsSystem"
import JOLT from "@/util/loading/JoltSyncLoader"

class SliderDriver extends Driver {
Expand Down Expand Up @@ -33,7 +33,7 @@ class SliderDriver extends Driver {

const motorSettings = this._constraint.GetMotorSettings()
const springSettings = motorSettings.mSpringSettings
springSettings.mFrequency = 20 * (1.0 / SIMULATION_PERIOD)
springSettings.mFrequency = 20 * (1.0 / GetLastDeltaT())
springSettings.mDamping = 0.995

motorSettings.mSpringSettings = springSettings
Expand Down
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