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);
}
}
