// Update is called once per frame
void Update()
{
Debug.DrawLine(new Vector3(0, 0), new Vector3(x, 0));
Debug.DrawLine(new Vector3(0, 0), new Vector3(0, y));
Debug.DrawLine(new Vector3(x, 0), new Vector3(x, y));
Debug.DrawLine(new Vector3(0, y), new Vector3(x, y));
// Spatial hashing
SpatialHash2D sh2d = new SpatialHash2D(x, y, h);
foreach (Point point in listPoint)
{
sh2d.Insert(point);
}
PVFS(listPoint, sh2d, g, Y, x, y, k, knear, pnear, h, r0, foutside);
}
public static void PVFS(List <Point> listPoint, SpatialHash2D sh2d, float g, Vector3 Y, float boundaryX, float boundaryY, float k, float knear, float pnear, float h, float r0, float foutside)
{
foreach (Point point in listPoint)
{
// Apply gravity
point.pos = point.transform.position;
point.v = Vdt(point.m, g, point.cd, Y, point.v);
// save previous position
point.prevPos = point.pos;
// advance to predicted position
point.pos = Pdt(point.v, point.pos);
}
// modify velocities with pairwise viscosity impulses
// applyViscosity
// add and remove springs, change rest lengths
// adjustSprings
// modify positions according to springs,
// double density relaxation, and collisions
// applySpringDisplacements
// doubleDensityRelaxation
foreach (Point pointI in listPoint)
{
float r = 0;
float rnear = 0;
float p;
float q;
Vector3 dirIJ;
// compute density and near-density
List <Point> neighborhood = sh2d.GetNearby(pointI);
foreach (Point pointJ in neighborhood)
{
dirIJ = pointJ.pos - pointI.pos;
q = dirIJ.magnitude / h;
if (q < 1)
{
r += Mathf.Pow(1 - q, 2);
rnear += Mathf.Pow(1 - q, 3);
}
}
// compute pressure and near-pressure
p = k * (r - r0);
pnear = knear * rnear;
Vector3 dx = Vector3.zero;
foreach (Point pointJ in neighborhood)
{
dirIJ = pointJ.pos - pointI.pos;
q = dirIJ.magnitude / h;
if (q < 1)
{
Vector3 D = (Time.fixedDeltaTime * Time.fixedDeltaTime) / pointI.m * (p * (1 - q) + pnear * Mathf.Pow(1 - q, 2)) * dirIJ.normalized;
pointJ.pos += D / 2;
dx = dx - D / 2;
}
}
pointI.pos += dx;
}
//resolveCollisions
// use previous position to compute next velocity
foreach (Point pointI in listPoint)
{
// Clamp
if (pointI.pos.y < 0)
{
pointI.pos += Vector3.up * (new Vector3(pointI.pos.x, 0) - pointI.pos).magnitude * foutside * (Time.fixedDeltaTime * Time.fixedDeltaTime) / pointI.m;
}
if (pointI.pos.y > boundaryY)
{
pointI.pos += Vector3.down * (new Vector3(pointI.pos.x, boundaryY) - pointI.pos).magnitude * foutside * (Time.fixedDeltaTime * Time.fixedDeltaTime) / pointI.m;
}
if (pointI.pos.x < 0)
{
pointI.pos += Vector3.right * (new Vector3(0, pointI.pos.y) - pointI.pos).magnitude * foutside * (Time.fixedDeltaTime * Time.fixedDeltaTime) / pointI.m;
}
if (pointI.pos.x > boundaryX)
{
pointI.pos += Vector3.left * (new Vector3(boundaryX, pointI.pos.y) - pointI.pos).magnitude * foutside * (Time.fixedDeltaTime * Time.fixedDeltaTime) / pointI.m;
}
pointI.transform.position = pointI.pos;
pointI.v = (pointI.pos - pointI.prevPos) / Time.fixedDeltaTime;
}
}
