static void smooth(DenseGrid3f grid, DenseGrid3f tmp, float alpha, int iters, int min_j = 1)
{
if (tmp == null)
{
tmp = new DenseGrid3f(grid);
}
int ni = grid.ni, nj = grid.nj, nk = grid.nk;
for (int iter = 0; iter < iters; ++iter)
{
for (int j = min_j; j < nj - 1; ++j)
{
for (int k = 1; k < nk - 1; ++k)
{
for (int i = 1; i < ni - 1; ++i)
{
float avg = 0;
foreach (Vector3i o in gIndices.GridOffsets26)
{
int xi = i + o.x, yi = j + o.y, zi = k + o.z;
float f = grid[xi, yi, zi];
avg += f;
}
avg /= 26.0f;
tmp[i, j, k] = (1 - alpha) * grid[i, j, k] + (alpha) * avg;
}
}
}
grid.swap(tmp);
}
}
void process_version1(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, column by column
for (int k = 0; k < nk; ++k)
{
for (int i = 0; i < ni; ++i)
{
bool in_support = false;
for (int j = nj - 1; j >= 0; j--)
{
float fcur = supportGrid[i, j, k];
if (fcur >= 0)
{
Vector3d cell_center = new Vector3f(i * dx, j * dx, k * dx) + origin;
if (in_support)
{
bool is_inside = distanceField.Value(ref cell_center) < 0;
if (is_inside)
{
supportGrid[i, j, k] = -3;
in_support = false;
}
else
{
supportGrid[i, j, k] = -1;
}
}
}
else
{
in_support = true;
}
}
}
}
// skeletonize each layer
// todo: would be nice to skeletonize the 3D volume.. ?
DenseGrid3i binary = new DenseGrid3i(ni, nj, nk, 0);
foreach (Vector3i idx in binary.Indices())
{
binary[idx] = (supportGrid[idx] < 0) ? 1 : 0;
}
for (int j = 0; j < nj; ++j)
{
skeletonize_layer(binary, j);
}
// debug thing
//VoxelSurfaceGenerator voxgen = new VoxelSurfaceGenerator() {
// Voxels = binary.get_bitmap()
//};
//voxgen.Generate();
//Util.WriteDebugMesh(voxgen.makemesh(), "c:\\scratch\\binary.obj");
// for skeleton voxels, we add some power
for (int j = 0; j < nj; ++j)
{
for (int k = 1; k < nk - 1; ++k)
{
for (int i = 1; i < ni - 1; ++i)
{
if (binary[i, j, k] > 0)
{
supportGrid[i, j, k] = -3;
}
//else
// supportGrid[i, j, k] = 1; // clear non-skeleton voxels
}
}
}
// power up the ground-plane voxels
for (int k = 0; k < nk; ++k)
{
for (int i = 0; i < ni; ++i)
{
if (supportGrid[i, 0, k] < 0)
{
supportGrid[i, 0, k] = -5;
}
}
}
#if true
DenseGrid3f smoothed = new DenseGrid3f(supportGrid);
float nbr_weight = 0.5f;
for (int iter = 0; iter < 15; ++iter)
{
// add some mass to skeleton voxels
for (int j = 0; j < nj; ++j)
{
for (int k = 1; k < nk - 1; ++k)
{
for (int i = 1; i < ni - 1; ++i)
{
if (binary[i, j, k] > 0)
{
supportGrid[i, j, k] = supportGrid[i, j, k] - nbr_weight / 25.0f;
}
}
}
}
for (int j = 0; j < nj; ++j)
{
for (int k = 1; k < nk - 1; ++k)
{
for (int i = 1; i < ni - 1; ++i)
{
int neg = 0;
float avg = 0, w = 0;
for (int n = 0; n < 8; ++n)
{
int xi = i + gIndices.GridOffsets8[n].x;
int zi = k + gIndices.GridOffsets8[n].y;
float f = supportGrid[xi, j, zi];
if (f < 0)
{
neg++;
}
avg += nbr_weight * f;
w += nbr_weight;
}
if (neg > -1)
{
avg += supportGrid[i, j, k];
w += 1.0f;
smoothed[i, j, k] = avg / w;
}
else
{
smoothed[i, j, k] = supportGrid[i, j, k];
}
}
}
}
supportGrid.swap(smoothed);
}
#endif
// hard-enforce that skeleton voxels stay inside
//for (int j = 0; j < nj; ++j) {
// for (int k = 1; k < nk - 1; ++k) {
// for (int i = 1; i < ni - 1; ++i) {
// if (binary[i, j, k] > 0)
// supportGrid[i, j, k] = Math.Min(supportGrid[i, j, k], - 1);
// }
// }
//}
}