pf_distance_field.cpp

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#include <distance_field/pf_distance_field.h>
#include <limits>

namespace distance_field
{

PFDistanceField::PFDistanceField(double size_x, double size_y, double size_z, double resolution,
    double origin_x, double origin_y, double origin_z):
  DistanceField<float>(size_x, size_y, size_z, resolution, origin_x, origin_y, origin_z, DT_INF),
  DT_INF(std::numeric_limits<float>::max())
{

}

PFDistanceField::~PFDistanceField()
{
}

void PFDistanceField::addPointsToField(const std::vector<tf::Vector3> points)
{
  int x, y, z;
  float init = 0.0;
  for (unsigned int i=0; i<points.size(); ++i)
  {
    bool valid = worldToGrid(points[i].x(), points[i].y(), points[i].z(), x, y, z);
    if (!valid)
      continue;
    setCell(x,y,z, init);
  }
  computeDT();
}

void PFDistanceField::computeDT()
{

  size_t nx = num_cells_[DIM_X];
  size_t ny = num_cells_[DIM_Y];
  size_t nz = num_cells_[DIM_Z];

    size_t     maxdim = std::max( nx, std::max(ny, nz) );
    FloatArray f(maxdim), ft(maxdim), zz(maxdim+1);
    IntArray   v(maxdim);

    // along z
    for (size_t y=0; y<ny; ++y) {
        for (size_t x=0; x<nx; ++x) {
            for (size_t z=0; z<nz; ++z) {
                f[z] = getCell(x,y,z);
            }
            dt(f, nz, ft, v, zz);
            for (size_t z=0; z<nz; ++z) {
                setCell(x,y,z,ft[z]);
            }
        }
    }

    // along y
    for (size_t z=0; z<nz; ++z) {
        for (size_t x=0; x<nx; ++x) {
            for (size_t y=0; y<ny; ++y) {
                f[y] = getCell(x,y,z);
            }
            dt(f, ny, ft, v, zz);
            for (size_t y=0; y<ny; ++y) {
                setCell(x,y,z,ft[y]);
            }
        }
    }

    // along x
    for (size_t z=0; z<nz; ++z) {
        for (size_t y=0; y<ny; ++y) {
            for (size_t x=0; x<nx; ++x) {
                f[x] = getCell(x,y,z);
            }
            dt(f, nx, ft, v, zz);
            for (size_t x=0; x<nx; ++x) {
                setCell(x,y,z,ft[x]);
            }
        }
    }

}


void PFDistanceField::dt(const FloatArray& f,
        size_t nn,
        FloatArray& ft,
        IntArray& v,
        FloatArray& z) {

/*    assert(f.size() >= nn);
    assert(ft.size() >= nn);
    assert(v.size() >= nn);
    assert(z.size() >= nn+1);
*/
    int n = nn;

    int k = 0;

    v[0] = 0;

    z[0] = -DT_INF;
    z[1] =  DT_INF;

    for (int q=1; q<n; ++q) {
        float s = ((f[q]+sqr(q))-(f[v[k]]+sqr(v[k])))/(2*q-2*v[k]);
        while (s <= z[k]) {
            --k;
            s = ((f[q]+sqr(q))-(f[v[k]]+sqr(v[k])))/(2*q-2*v[k]);
        }
        ++k;
        v[k] = q;
        z[k] = s;
        z[k+1] = DT_INF;
    }

    k = 0;
    for (int q=0; q<n; ++q) {
        while (z[k+1] < q) { ++k; }
        ft[q] = sqr(q-v[k]) + f[v[k]];
    }

}


void PFDistanceField::reset()
{
  VoxelGrid<float>::reset(DT_INF);
}

}