private Vector3 PressureDragForce(WaterTriangle triangle)
{
var velocity = triangle.Velocity.magnitude;
velocity = velocity / _optionsController.PressureOptions.ReferenceSpeed;
var pressureDragForce = new Vector3();
if (triangle.CosTheta > 0f)
{
var pressureCoefficient1 = _optionsController.PressureOptions.PressureCoefficient1;
var pressureCoefficient2 = _optionsController.PressureOptions.PressureCoefficient2;
var pressureFalloff = _optionsController.PressureOptions.PressureFalloff;
pressureDragForce = -(pressureCoefficient1 * velocity + pressureCoefficient2 * (velocity * velocity)) * triangle.Area * Mathf.Pow(triangle.CosTheta, pressureFalloff) * _transform.TransformVector(triangle.Normal);
}
else
{
var suctionCoefficient1 = _optionsController.PressureOptions.SuctionCoefficient1;
var suctionCoefficient2 = _optionsController.PressureOptions.SuctionCoefficient2;
var suctionFalloff = _optionsController.PressureOptions.SuctionFalloff;
pressureDragForce = (suctionCoefficient1 * velocity + suctionCoefficient2 * (velocity * velocity)) * triangle.Area * Mathf.Pow(Mathf.Abs(triangle.CosTheta), suctionFalloff) * _transform.TransformVector(triangle.Normal);
}
if (_optionsController.PressureDebugEnabled)
{
Debug.DrawRay(_transform.TransformPoint(triangle.Center), pressureDragForce * _optionsController.DebugUIScale, Color.magenta);
}
return(pressureDragForce);
}
private Vector3 BouancyForce(WaterTriangle triangle)
{
var forceVector = RhoWater * Physics.gravity.y * -triangle.DepthAtCenter * triangle.Area * _transform.TransformVector(triangle.Normal);
forceVector.x = forceVector.z = 0f;
if (_optionsController.BounancyDebugEnabled)
{
var color = forceVector.y > 0 ? Color.green : Color.red;
Debug.DrawRay(_transform.TransformPoint(triangle.Center), forceVector * _optionsController.DebugUIScale, color);
}
return(forceVector);
}
private Vector3 ViscousWaterResistanceForce(WaterTriangle triangle, float resistanceCoefficient)
{
var normal = _transform.TransformVector(triangle.Normal);
var velocity = triangle.Velocity;
var velocityTangent = Vector3.Cross(normal, Vector3.Cross(velocity, normal) / normal.magnitude) / normal.magnitude;
var tangentialDirection = velocityTangent.normalized * -1f;
var tangentialVelocity = triangle.Velocity.magnitude * tangentialDirection;
var viscousWaterResistanceForce = 0.5f * RhoWater * tangentialVelocity.magnitude * tangentialVelocity * triangle.Area * resistanceCoefficient;
if (_optionsController.ViscosityDebugEnabled)
{
Debug.DrawRay(_transform.TransformPoint(triangle.Center), velocity * _optionsController.DebugUIScale, Color.blue);
Debug.DrawRay(_transform.TransformPoint(triangle.Center), normal * _optionsController.DebugUIScale, Color.white);
Debug.DrawRay(_transform.TransformPoint(triangle.Center), tangentialDirection * _optionsController.DebugUIScale, Color.black);
Debug.DrawRay(_transform.TransformPoint(triangle.Center), tangentialVelocity * _optionsController.DebugUIScale, Color.gray);
Debug.DrawRay(_transform.TransformPoint(triangle.Center), viscousWaterResistanceForce * _optionsController.DebugUIScale, Color.red);
}
return(viscousWaterResistanceForce);
}
private void AnalyzeTriangle(int originalMeshIndex, Vector3 pointA, Vector3 pointB, Vector3 pointC)
{
var center = (pointA + pointB + pointC) / 3f;
//Area of the triangle
var a = Vector3.Distance(pointA, pointB);
var c = Vector3.Distance(pointC, pointA);
var area = a * c * Mathf.Sin(Vector3.Angle(pointB - pointA, pointC - pointA) * Mathf.Deg2Rad) / 2f;
var triangle = new WaterTriangle
{
Vertices = new[] { pointA, pointB, pointC },
Center = center,
DepthAtCenter = _boatTrans.TransformPoint(center).y,
Normal = Vector3.Cross(pointB - pointA, pointC - pointA).normalized,
Area = area,
OriginalMeshIndex = originalMeshIndex
};
UnderwaterTriangles.Add(triangle);
_slammingForces[originalMeshIndex].SubmergedArea += triangle.Area;
}
private void CalculateTriangleVelocity(WaterTriangle triangle)
{
triangle.Velocity = _rigidbody.GetRelativePointVelocity(_transform.TransformVector(triangle.Center));
triangle.CosTheta = Vector3.Dot(triangle.Velocity.normalized, _transform.TransformVector(triangle.Normal));
}
private Vector3 SlammingForce(SlammingForce slammingData, WaterTriangle triangle, float boatArea, float boatMass)
{
//To capture the response of the fluid to sudden accelerations or penetrations
//Add slamming if the normal is in the same direction as the velocity (the triangle is not receding from the water)
//Also make sure thea area is not 0, which it sometimes is for some reason
if (triangle.CosTheta < 0f || slammingData.OriginalArea <= 0f)
{
return(Vector3.zero);
}
var deltaTime = Time.fixedDeltaTime;
//Step 1 - Calculate acceleration
//Volume of water swept per second
Vector3 dV = slammingData.SubmergedArea * slammingData.Velocity;
Vector3 dV_previous = slammingData.PreviousSubmergedArea * slammingData.PreviousVelocity;
//Calculate the acceleration of the center point of the original triangle (not the current underwater triangle)
//But the triangle the underwater triangle is a part of
Vector3 accVec = (dV - dV_previous) / (slammingData.OriginalArea * deltaTime);
//The magnitude of the acceleration
float acc = accVec.magnitude;
//Step 2 - Calculate slamming force
// F = clamp(acc / acc_max, 0, 1)^p * cos(theta) * F_stop
// p - power to ramp up slamming force - should be 2 or more
// F_stop = m * v * (2A / S)
// m - mass of the entire boat
// v - velocity
// A - this triangle's area
// S - total surface area of the entire boat
Vector3 F_stop = boatMass * triangle.Velocity * (2f * triangle.Area / boatArea);
//float p = DebugPhysics.current.p;
//float acc_max = DebugPhysics.current.acc_max;
float p = _optionsController.SlammingOptions.RampingPower;
float acc_max = (dV / (slammingData.OriginalArea * deltaTime)).magnitude;
float slammingCheat = _optionsController.SlammingOptions.SlammingCheat;
Vector3 slammingForce = Mathf.Pow(Mathf.Clamp01(acc / acc_max), p) * triangle.CosTheta * F_stop * slammingCheat;
//Vector3 slammingForce = F_stop;
//The force acts in the opposite direction
slammingForce *= -1f;
//slammingForce = CheckForceIsValid(slammingForce, "Slamming");
if (_optionsController.SlammingDebugEnabled)
{
Debug.DrawRay(_transform.TransformPoint(triangle.Center), slammingForce * _optionsController.DebugUIScale, Color.yellow);
}
return(slammingForce);
}
