//Add all forces that act on the squares below the water
void AddUnderWaterForces()
{
//Get all triangles
List <triangleData> underWaterTriangleData = modifyBoatMesh.underWaterTriangleData;
for (int i = 0; i < underWaterTriangleData.Count; i++)
{
//use only unerwater triangle
triangleData triangleData = underWaterTriangleData[i];
//Calculate the buoyancy force
Vector3 buoyancyForce = BuoyancyForce(rhoWater, triangleData);
//Add the force to the boat
boatRB.AddForceAtPosition(buoyancyForce, triangleData.center);
//Debug
//Normal
Debug.DrawRay(triangleData.center, triangleData.normal * 0.5f, Color.white);
//Buoyancy
Debug.DrawRay(triangleData.center, buoyancyForce.normalized * -0.2f, Color.blue);
}
}
//The buoyancy force so the boat can float
private Vector3 BuoyancyForce(float rho, triangleData triangleData)
{
//Buoyancy is a hydrostatic force - it's there even if the water isn't flowing or if the boat stays still
// F_buoyancy = rho * g * V
// rho - density of the mediaum you are in
// g - gravity
// V - volume of fluid directly above the curved surface
// V = z * S * n
// z - distance to surface
// S - surface area
// n - normal to the surface
Vector3 buoyancyForce = rho * Physics.gravity.y * triangleData.distanceToSurface * triangleData.area * triangleData.normal;
//The vertical component of the hydrostatic forces don't cancel out but the horizontal do
buoyancyForce.x = 0f;
buoyancyForce.z = 0f;
return(buoyancyForce);
}