C++ UPrimitiveComponent::AddForceAtLocation方法代码示例

//.........这里部分代码省略.........
					//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);
}

void UVaOceanBuoyancyComponent::PerformWaveReaction(float DeltaTime)
{
	AActor* MyOwner = GetOwner();

	if (!UpdatedComponent || MyOwner == NULL)
	{
		return;
	}
	UPrimitiveComponent* OldPrimitive = Cast<UPrimitiveComponent>(UpdatedComponent);

	const FVector OldLocation = MyOwner->GetActorLocation();
	const FRotator OldRotation = MyOwner->GetActorRotation();
	const FVector OldLinearVelocity = OldPrimitive->GetPhysicsLinearVelocity();
	const FVector OldAngularVelocity = OldPrimitive->GetPhysicsAngularVelocity();
	const FVector OldCenterOfMassWorld = OldLocation + OldRotation.RotateVector(COMOffset);
	const FVector OwnerScale = MyOwner->GetActorScale();

	// XYZ === Throttle, Steering, Rise == Forwards, Sidewards, Upwards
	FVector X, Y, Z;
	GetAxes(OldRotation, X, Y, Z);

	// Process tension dots and get torque from wind/waves
	for (FVector TensionDot : TensionDots)
	{
		// Translate point to world coordinates
		FVector TensionDotDisplaced = OldRotation.RotateVector(TensionDot + COMOffset);
		FVector TensionDotWorld = OldLocation + TensionDotDisplaced;

		// Get point depth
		float DotAltitude = GetAltitude(TensionDotWorld);

		// Don't process dots above water
		if (DotAltitude > 0)
		{
			continue;
		}
		
		// Surface normal (not modified!)
		FVector DotSurfaceNormal = GetSurfaceNormal(TensionDotWorld) * GetSurfaceWavesNum();
		// Modify normal with real Z value and normalize it
		DotSurfaceNormal.Z = GetOceanLevel(TensionDotWorld);
		DotSurfaceNormal.Normalize();

		// Point dynamic pressure [http://en.wikipedia.org/wiki/Dynamic_pressure]
		// rho = 1.03f for ocean water
		FVector WaveVelocity = GetWaveVelocity(TensionDotWorld);
		float DotQ = 0.515f * FMath::Square(WaveVelocity.Size());
		FVector WaveForce = FVector(0.0,0.0,1.0) * DotQ /* DotSurfaceNormal*/ * (-DotAltitude) * TensionDepthFactor;
		
		// We don't want Z to be affected by DotQ
		WaveForce.Z /= DotQ;

		// Scale to DeltaTime to break FPS addiction
		WaveForce *= DeltaTime;

		// Apply actor scale
		WaveForce *= OwnerScale.X;// *OwnerScale.Y * OwnerScale.Z;

		OldPrimitive->AddForceAtLocation(WaveForce * Mass, TensionDotWorld);
	}

	// Static metacentric forces (can be useful on small waves)
	if (bUseMetacentricForces)
	{
		FVector TensionTorqueResult = FVector(0.0f, 0.0f, 0.0f);

		// Calc recovering torque (transverce)
		FRotator RollRot = FRotator(0.0f, 0.0f, 0.0f);
		RollRot.Roll = OldRotation.Roll;
		FVector MetacenterDisplaced = RollRot.RotateVector(TransverseMetacenter + COMOffset);
		TensionTorqueResult += X * FVector::DotProduct((TransverseMetacenter - MetacenterDisplaced), 
			FVector(0.0f, -1.0f, 0.0f)) * TensionTorqueRollFactor;

		// Calc recovering torque (longitude)
		FRotator PitchRot = FRotator(0.0f, 0.0f, 0.0f);
		PitchRot.Pitch = OldRotation.Pitch;
		MetacenterDisplaced = PitchRot.RotateVector(LongitudinalMetacenter + COMOffset);
		TensionTorqueResult += Y * FVector::DotProduct((LongitudinalMetacenter - MetacenterDisplaced), 
			FVector(1.0f, 0.0f, 0.0f)) * TensionTorquePitchFactor;

		// Apply torque
		TensionTorqueResult *= DeltaTime;
		TensionTorqueResult *= OwnerScale.X;// *OwnerScale.Y * OwnerScale.Z;
		OldPrimitive->AddTorque(TensionTorqueResult);
	}
}