//Note that the value cache at grid vertices are internal grid (1/2 width).
//This allows caching values at edge and face center points.
private float EvaluateAtInternalGrid(GridCoordinate coord)
{
var g = coord.GetGridLong(_size);
var tryRead = ReadCache(g);
if (tryRead.HasValue)
{
return(tryRead.Value);
}
else
{
var val = _function.Get(null, coord.ToVector() / 2);
AddToCache(g, val);
return(val);
}
}
private GridEdge FindFirst()
{
GridCoordinate g0 = new GridCoordinate(0, 0, 0);
GridCoordinate gMove = new GridCoordinate(1, 0, 0);
if (_cache.EvaluateAtGrid(g0, GridCoordinate.Zero) < 0)
{
throw new Exception("Origin not contained in shape");
}
var g1 = g0 + gMove;
while (_cache.EvaluateAtGrid(g1, GridCoordinate.Zero) > 0)
{
g0 = g1;
g1 += gMove;
}
return(new GridEdge(g0, 0));
}
public Vector3 CalculateOptimalPoint(GridCoordinate grid)
{
if (_optimalPoint.TryGetValue(grid.GetGridLong(_size), out var ret))
{
return(ret);
}
var internalGrid = grid + grid;
_optimizer.Reset();
for (var axis = 0; axis < 3; ++axis)
{
var edgeHalfDiff = _axisIncList[axis];
var edgeFullDiff = edgeHalfDiff + edgeHalfDiff;
for (var i = 0; i < 4; ++i)
{
var low = internalGrid + _gridEdgeList[axis * 4 + i];
var high = low + edgeFullDiff;
var lowVal = EvaluateAtInternalGrid(low);
var highVal = EvaluateAtInternalGrid(high);
if (Math.Sign(lowVal) != Math.Sign(highVal))
{
var pos = (0 - lowVal) / (highVal - lowVal);
//TODO simplify
var r = pos * high.ToVector() + (1 - pos) * low.ToVector() - internalGrid.ToVector();
var g = Vector3.Normalize(EvaluateGradient(low + edgeHalfDiff));
_optimizer.AddCrossEdge(r / 2, g);
}
}
}
ret = grid.ToVector() + _optimizer.Optimize();
_optimalPoint.Add(grid.GetGridLong(_size), ret);
return(ret);
}
private int GetVertex(GridCoordinate grid)
{
return(_gridVertex[grid.GetGridLong(_size)]);
}
public GridEdge(GridCoordinate coord, int axis)
{
Coord = coord;
Axis = axis;
}
private float EvaluateDifference(GridCoordinate internalGrid, GridCoordinate diff)
{
return(EvaluateAtInternalGrid(internalGrid + diff) - EvaluateAtInternalGrid(internalGrid - diff));
}
public float EvaluateAtGrid(GridCoordinate coord, GridCoordinate halfOffset)
{
return(EvaluateAtInternalGrid(coord + coord + halfOffset));
}