void UBuoyancyForceComponent::TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction *ThisTickFunction) { Super::TickComponent(DeltaTime, TickType, ThisTickFunction); // If disabled or we are not attached to a parent component, return. if (!bIsActive || !GetAttachParent()) return; if (!OceanManager) return; UPrimitiveComponent* BasePrimComp = Cast<UPrimitiveComponent>(GetAttachParent()); if (!BasePrimComp) return; if (!BasePrimComp->IsSimulatingPhysics()) { if (!SnapToSurfaceIfNoPhysics) return; UE_LOG(LogTemp, Warning, TEXT("Running in no physics mode..")); float waveHeight = OceanManager->GetWaveHeightValue(BasePrimComp->GetComponentLocation(), World, true, TwoGerstnerIterations).Z; BasePrimComp->SetWorldLocation(FVector(BasePrimComp->GetComponentLocation().X, BasePrimComp->GetComponentLocation().Y, waveHeight)); return; } //Get gravity float Gravity = BasePrimComp->GetPhysicsVolume()->GetGravityZ(); //--------------- If Skeletal --------------- USkeletalMeshComponent* SkeletalComp = Cast<USkeletalMeshComponent>(GetAttachParent()); if (SkeletalComp && ApplyForceToBones) { TArray<FName> BoneNames; SkeletalComp->GetBoneNames(BoneNames); for (int32 Itr = 0; Itr < BoneNames.Num(); Itr++) { FBodyInstance* BI = SkeletalComp->GetBodyInstance(BoneNames[Itr], false); if (BI && BI->IsValidBodyInstance() && BI->bEnableGravity) //Buoyancy doesn't exist without gravity { bool isUnderwater = false; //FVector worldBoneLoc = SkeletalComp->GetBoneLocation(BoneNames[Itr]); FVector worldBoneLoc = BI->GetCOMPosition(); //Use center of mass of the bone's physics body instead of bone's location FVector waveHeight = OceanManager->GetWaveHeightValue(worldBoneLoc, World, true, TwoGerstnerIterations); float BoneDensity = MeshDensity; float BoneTestRadius = FMath::Abs(TestPointRadius); float SignedBoneRadius = FMath::Sign(Gravity) * TestPointRadius; //Direction of radius (test radius is actually a Z offset, should probably rename it!). Just in case we need an upside down world. //Get density & radius from the override array, if available. for (int pointIndex = 0; pointIndex < BoneOverride.Num(); pointIndex++) { FStructBoneOverride Override = BoneOverride[pointIndex]; if (Override.BoneName.IsEqual(BoneNames[Itr])) { BoneDensity = Override.Density; BoneTestRadius = FMath::Abs(Override.TestRadius); SignedBoneRadius = FMath::Sign(Gravity) * BoneTestRadius; } } //If test point radius is below water surface, add buoyancy force. if (waveHeight.Z > (worldBoneLoc.Z + SignedBoneRadius)) { isUnderwater = true; float DepthMultiplier = (waveHeight.Z - (worldBoneLoc.Z + SignedBoneRadius)) / (BoneTestRadius * 2); DepthMultiplier = FMath::Clamp(DepthMultiplier, 0.f, 1.f); float Mass = SkeletalComp->CalculateMass(BoneNames[Itr]); //Mass of this specific bone's physics body /** * -------- * Buoyancy force formula: (Volume(Mass / Density) * Fluid Density * -Gravity) / Total Points * Depth Multiplier * -------- */ float BuoyancyForceZ = Mass / BoneDensity * FluidDensity * -Gravity * DepthMultiplier; //Velocity damping. FVector DampingForce = -BI->GetUnrealWorldVelocity() * VelocityDamper * Mass * DepthMultiplier; //Experimental xy wave force if (EnableWaveForces) { float waveVelocity = FMath::Clamp(BI->GetUnrealWorldVelocity().Z, -20.f, 150.f) * (1 - DepthMultiplier); DampingForce += FVector(OceanManager->GlobalWaveDirection.X, OceanManager->GlobalWaveDirection.Y, 0) * Mass * waveVelocity * WaveForceMultiplier; } //Add force to this bone BI->AddForce(FVector(DampingForce.X, DampingForce.Y, DampingForce.Z + BuoyancyForceZ)); //BasePrimComp->AddForceAtLocation(FVector(DampingForce.X, DampingForce.Y, DampingForce.Z + BuoyancyForceZ), worldBoneLoc, BoneNames[Itr]); } //Apply fluid damping & clamp velocity if (isUnderwater) { BI->SetLinearVelocity(-BI->GetUnrealWorldVelocity() * (FluidLinearDamping / 10), true); BI->SetAngularVelocity(-BI->GetUnrealWorldAngularVelocity() * (FluidAngularDamping / 10), true); //Clamp the velocity to MaxUnderwaterVelocity if (ClampMaxVelocity && BI->GetUnrealWorldVelocity().Size() > MaxUnderwaterVelocity) { FVector Velocity = BI->GetUnrealWorldVelocity().GetSafeNormal() * MaxUnderwaterVelocity; BI->SetLinearVelocity(Velocity, false); } } if (DrawDebugPoints) { FColor DebugColor = FLinearColor(0.8, 0.7, 0.2, 0.8).ToRGBE(); if (isUnderwater) { DebugColor = FLinearColor(0, 0.2, 0.7, 0.8).ToRGBE(); } //Blue color underwater, yellow out of watter DrawDebugSphere(World, worldBoneLoc, BoneTestRadius, 8, DebugColor); } } } return; } //-------------------------------------------------------- float TotalPoints = TestPoints.Num(); if (TotalPoints < 1) return; int PointsUnderWater = 0; for (int pointIndex = 0; pointIndex < TotalPoints; pointIndex++) { if (!TestPoints.IsValidIndex(pointIndex)) return; //Array size changed during runtime bool isUnderwater = false; FVector testPoint = TestPoints[pointIndex]; FVector worldTestPoint = BasePrimComp->GetComponentTransform().TransformPosition(testPoint); FVector waveHeight = OceanManager->GetWaveHeightValue(worldTestPoint, World, !EnableWaveForces, TwoGerstnerIterations); //Direction of radius (test radius is actually a Z offset, should probably rename it!). Just in case we need an upside down world. float SignedRadius = FMath::Sign(BasePrimComp->GetPhysicsVolume()->GetGravityZ()) * TestPointRadius; //If test point radius is below water surface, add buoyancy force. if (waveHeight.Z > (worldTestPoint.Z + SignedRadius) && BasePrimComp->IsGravityEnabled()) //Buoyancy doesn't exist without gravity { PointsUnderWater++; isUnderwater = true; float DepthMultiplier = (waveHeight.Z - (worldTestPoint.Z + SignedRadius)) / (TestPointRadius * 2); DepthMultiplier = FMath::Clamp(DepthMultiplier, 0.f, 1.f); //If we have a point density override, use the overridden value instead of MeshDensity float PointDensity = PointDensityOverride.IsValidIndex(pointIndex) ? PointDensityOverride[pointIndex] : MeshDensity; /** * -------- * Buoyancy force formula: (Volume(Mass / Density) * Fluid Density * -Gravity) / Total Points * Depth Multiplier * -------- */ float BuoyancyForceZ = BasePrimComp->GetMass() / PointDensity * FluidDensity * -Gravity / TotalPoints * DepthMultiplier; //Experimental velocity damping using VelocityAtPoint. FVector DampingForce = -GetUnrealVelocityAtPoint(BasePrimComp, worldTestPoint) * VelocityDamper * BasePrimComp->GetMass() * DepthMultiplier; //Experimental xy wave force if (EnableWaveForces) { DampingForce += BasePrimComp->GetMass() * FVector2D(waveHeight.X, waveHeight.Y).Size() * FVector(OceanManager->GlobalWaveDirection.X, OceanManager->GlobalWaveDirection.Y, 0) * WaveForceMultiplier / TotalPoints; //float waveVelocity = FMath::Clamp(GetUnrealVelocityAtPoint(BasePrimComp, worldTestPoint).Z, -20.f, 150.f) * (1 - DepthMultiplier); //DampingForce += OceanManager->GlobalWaveDirection * BasePrimComp->GetMass() * waveVelocity * WaveForceMultiplier / TotalPoints; } //Add force for this test point BasePrimComp->AddForceAtLocation(FVector(DampingForce.X, DampingForce.Y, DampingForce.Z + BuoyancyForceZ), worldTestPoint); } if (DrawDebugPoints) { FColor DebugColor = FLinearColor(0.8, 0.7, 0.2, 0.8).ToRGBE(); if (isUnderwater) { DebugColor = FLinearColor(0, 0.2, 0.7, 0.8).ToRGBE(); } //Blue color underwater, yellow out of watter DrawDebugSphere(World, worldTestPoint, TestPointRadius, 8, DebugColor); } } //Clamp the velocity to MaxUnderwaterVelocity if there is any point underwater if (ClampMaxVelocity && PointsUnderWater > 0 && BasePrimComp->GetPhysicsLinearVelocity().Size() > MaxUnderwaterVelocity) { FVector Velocity = BasePrimComp->GetPhysicsLinearVelocity().GetSafeNormal() * MaxUnderwaterVelocity; BasePrimComp->SetPhysicsLinearVelocity(Velocity); } //Update damping based on number of underwater test points BasePrimComp->SetLinearDamping(_baseLinearDamping + FluidLinearDamping / TotalPoints * PointsUnderWater); BasePrimComp->SetAngularDamping(_baseAngularDamping + FluidAngularDamping / TotalPoints * PointsUnderWater); }