/// <summary>
/// Sets the facing of the cell
/// </summary>
/// <param name="direction"></param>
public void Reorientate(Vector3 direction)
{
direction.unitVect();
orientation.x = direction.x;
orientation.y = direction.y;
orientation.z = direction.z;
}
/// <summary>
/// Private method for performing the spatial simulation.
/// </summary>
/// <param name="cell"></param>
/// <param name="currentState"></param>
/// <param name="time"></param>
/// <param name="StepTime"></param>
private void SpatialSimulator(CellInstance cell, StateSnapshot currentState, double time, double StepTime)
{
Vector3 p = cell.CellInstanceSpatialContext.Position;
Vector3 v = cell.CellInstanceSpatialContext.Velocity;
Vector3 ang = cell.CellInstanceSpatialContext.Orientation;
float visc = currentState.SimulationEnvironment.Viscosity;
float h = (float)StepTime;
//viscous drag (Stokes's drag)
v.x += -visc * h * v.x * 1.5f;
v.y += -visc * h * v.y * 1.5f;
v.z += -visc * h * v.z * 1.5f;
//cell collisions
if (currentState.SimulationEnvironment.EnableCellCollisions)
{
foreach (CellInstance cellB in currentState.Cells)
{
if (cell != cellB) //avoid collision with self
{
//the vector from the centre of this cell to cellB
Vector3 dist = new Vector3(p.x - cellB.CellInstanceSpatialContext.Position.x,
p.y - cellB.CellInstanceSpatialContext.Position.y,
p.z - cellB.CellInstanceSpatialContext.Position.z);
float distMag = dist.magnitude();
if (distMag < cell.CellInstanceSpatialContext.Radius*0.001 + cellB.CellInstanceSpatialContext.Radius*0.001)
{
/*
* Collision occured: accelerate this cell away from the centre of the cell it is colliding with:
*/
dist.unitVect(); //normalize
dist.x *= -h*0.1f;
dist.y *= -h*0.1f;
dist.z *= -h*0.1f;
//accelerate this cell and the one it collided with in oppose directions:
v.x -= dist.x;
v.y -= dist.y;
v.z -= dist.z;
cellB.CellInstanceSpatialContext.Accelerate(dist);
}
}
}
}
//positional change
p.x += v.x * h;
p.y += v.y * h;
p.z += v.z * h;
//check that boundary conditions are maintained (most of the time this will be true, and will be the only test needed)
if (!currentState.SimulationEnvironment.Boundary.InsideBoundary(p))
{
/*
* If the cell is not inside the environment boundary, we move it back
* and attempt to move the cell by individual components (this allows
* the cell to "slide" along the edges of the boundary without
* breaking the boundary conditions). In most cases these three boundary
* checks should not be necessary
*/
//begin by checking x component, so move back y and z components
p.y -= v.y * h;
p.z -= v.z * h;
if (!currentState.SimulationEnvironment.Boundary.InsideBoundary(p))
{
//x failed, so move back x
p.x -= v.x * h;
}
//check y component
p.y += v.y * h;
if (!currentState.SimulationEnvironment.Boundary.InsideBoundary(p))
{
//y failed
p.y -= v.y * h;
}
//check z component
p.z += v.z * h;
if (!currentState.SimulationEnvironment.Boundary.InsideBoundary(p))
{
//z failed
p.z -= v.z * h;
}
}
cell.CellInstanceSpatialContext.Position = p;
cell.CellInstanceSpatialContext.Velocity = v;
cell.CellInstanceSpatialContext.Orientation = ang;
}
