public void Execute([ReadOnly] ref TriangleData triangleData)
{
var currentGlobals = new TriangleGlobals(L2W, triangleData);
// TODO: Add water mesh height calculation for wave physics.
// Assuming water is flat and calm
var h1 = new VertexData(currentGlobals.G1, currentGlobals.G1.y, 0);
var h2 = new VertexData(currentGlobals.G2, currentGlobals.G2.y, 1);
var h3 = new VertexData(currentGlobals.G3, currentGlobals.G3.y, 2);
// All above water, ignore.
if (h1.Height > 0 && h2.Height > 0 && h3.Height > 0)
{
return;
}
// All below water.
if (h1.Height < 0 && h2.Height < 0 && h3.Height < 0)
{
UnderwaterTriangles.Enqueue(currentGlobals);
return;
}
// Sorting points in descending order
if (h1.Height < h3.Height)
{
Swap(ref h1, ref h3);
}
if (h1.Height < h2.Height)
{
Swap(ref h1, ref h2);
}
if (h2.Height < h3.Height)
{
Swap(ref h2, ref h3);
}
// Mathematics for the following two originated from:
// https://gamasutra.com/view/news/237528/Water_interaction_model_for_boats_in_video_games.php
// And overall code structure and commenting adapted from:
// https://www.habrador.com/tutorials/unity-boat-tutorial/3-buoyancy/
if (h2.Height < 0)
{
AddTrianglesOneAboveWater(h1, h2, h3);
}
else
{
AddTrianglesTwoAboveWater(h1, h2, h3);
}
}
private static float3 BuoyancyForce(float rho, TriangleGlobals triangle)
{
//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
var buoyancyForce = rho * Physics.gravity.y * triangle.DistanceToSurface()
* triangle.SurfaceArea() * triangle.Normal();
//The vertical component of the hydrostatic forces don't cancel out but the horizontal do
buoyancyForce.x = 0f;
buoyancyForce.z = 0f;
return(buoyancyForce);
}
