private void SetCrossings(VoxelStencil stencil, int xStart, int xEnd, int yStart, int yEnd)
{
bool crossHorizontalGap = false;
bool lastVerticalRow = false;
bool crossVerticalGap = false;
if (xStart > 0)
{
xStart -= 1;
}
if (xEnd == resolution - 1)
{
xEnd -= 1;
crossHorizontalGap = xNeighbor != null;
}
if (yStart > 0)
{
yStart -= 1;
}
if (yEnd == resolution - 1)
{
yEnd -= 1;
lastVerticalRow = true;
crossVerticalGap = yNeighbor != null;
}
Voxel a, b;
for (int y = yStart; y <= yEnd; y++)
{
int i = y * resolution + xStart;
b = voxels[i];
for (int x = xStart; x <= xEnd; x++, i++)
{
a = b;
b = voxels[i + 1];
stencil.SetHorizontalCrossing(a, b);
stencil.SetVerticalCrossing(a, voxels[i + resolution]);
}
stencil.SetVerticalCrossing(b, voxels[i + resolution]);
if (crossHorizontalGap)
{
dummyX.BecomeXDummyOf(xNeighbor.voxels[y * resolution], gridSize);
stencil.SetHorizontalCrossing(b, dummyX);
}
}
if (lastVerticalRow)
{
int i = voxels.Length - resolution + xStart;
b = voxels[i];
for (int x = xStart; x <= xEnd; x++, i++)
{
a = b;
b = voxels[i + 1];
stencil.SetHorizontalCrossing(a, b);
if (crossVerticalGap)
{
dummyY.BecomeYDummyOf(yNeighbor.voxels[x], gridSize);
stencil.SetVerticalCrossing(a, dummyY);
}
}
if (crossVerticalGap)
{
dummyY.BecomeYDummyOf(yNeighbor.voxels[xEnd + 1], gridSize);
stencil.SetVerticalCrossing(b, dummyY);
}
if (crossHorizontalGap)
{
dummyX.BecomeXDummyOf(xNeighbor.voxels[voxels.Length - resolution], gridSize);
stencil.SetHorizontalCrossing(b, dummyX);
}
}
}
