static void diffuse(DenseGrid2f grid, float t, Func<int, int, bool> skipF)
{
int ni = grid.ni, nj = grid.nj;
DenseGrid2f dilated = new DenseGrid2f(grid);
for (int j = 1; j < nj - 1; ++j) {
for (int i = 1; i < ni - 1; ++i) {
if (skipF != null && skipF(i, j))
continue;
if (grid[i, j] < 0) {
foreach (Vector2i o in gIndices.GridOffsets8) {
float df = (o.LengthSquared > 1) ? -1f : -0.707f;
df *= t;
dilated[i + o.x, j + o.y] = Math.Min(dilated[i + o.x, j + o.y], df);
//dilated[i + o.x, j + o.y] += df;
}
}
}
}
grid.swap(dilated);
}
void process_version2(DenseGrid3f supportGrid, DenseGridTrilinearImplicit distanceField)
{
int ni = supportGrid.ni, nj = supportGrid.nj, nk = supportGrid.nk;
float dx = (float)CellSize;
Vector3f origin = this.GridOrigin;
// sweep values down layer by layer
DenseGrid2f prev = supportGrid.get_slice(nj - 1, 1);
DenseGrid2f tmp = new DenseGrid2f(prev);
Bitmap3 bmp = new Bitmap3(new Vector3i(ni, nj, nk));
for (int j = nj - 2; j >= 0; j--) {
// skeletonize prev layer
DenseGrid2i prev_skel = binarize(prev, 0.0f);
skeletonize(prev_skel, null, 2);
//dilate_loners(prev_skel, null, 2);
if (j == 0) {
dilate(prev_skel, null, true);
dilate(prev_skel, null, true);
}
for (int k = 1; k < nk - 1; ++k) {
for (int i = 1; i < ni - 1; ++i)
bmp[new Vector3i(i,j,k)] = (prev_skel[i, k] == 1) ? true : false;
}
smooth(prev, tmp, 0.5f, 5);
DenseGrid2f cur = supportGrid.get_slice(j, 1);
cur.set_min(prev);
for (int k = 1; k < nk - 1; ++k) {
for (int i = 1; i < ni - 1; ++i) {
float skelf = prev_skel[i, k] > 0 ? -1.0f : int.MaxValue;
cur[i, k] = Math.Min(cur[i, k], skelf);
if (cur[i, k] < 0) {
Vector3d cell_center = new Vector3f(i * dx, j * dx, k * dx) + origin;
if (distanceField.Value(ref cell_center) < -CellSize)
cur[i, k] = 1;
}
}
}
for (int k = 1; k < nk - 1; ++k) {
for (int i = 1; i < ni - 1; ++i) {
if (is_loner(prev_skel, i, k)) {
foreach (Vector2i d in gIndices.GridOffsets8) {
float f = 1.0f / (float)Math.Sqrt(d.x*d.x + d.y*d.y);
cur[i + d.x, k + d.y] += -0.25f * f;
}
}
}
}
for (int k = 1; k < nk - 1; ++k) {
for (int i = 1; i < ni - 1; ++i) {
supportGrid[i, j, k] = cur[i, k];
}
}
prev.swap(cur);
}
VoxelSurfaceGenerator gen = new VoxelSurfaceGenerator() { Voxels = bmp };
gen.Generate();
Util.WriteDebugMesh(gen.Meshes[0], "c:\\scratch\\binary.obj");
}