voxel_grid.h

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 * Author: Eitan Marder-Eppstein
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#ifndef VOXEL_GRID_VOXEL_GRID_H
#define VOXEL_GRID_VOXEL_GRID_H

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>
#include <limits.h>
#include <algorithm>
#include <ros/console.h>
#include <ros/assert.h>

namespace voxel_grid
{

enum VoxelStatus {
  FREE = 0,
  UNKNOWN = 1,
  MARKED = 2,
};

class VoxelGrid
{
public:
  VoxelGrid(unsigned int size_x, unsigned int size_y, unsigned int size_z);

  ~VoxelGrid();

  void resize(unsigned int size_x, unsigned int size_y, unsigned int size_z);

  void reset();
  uint32_t* getData() { return data_; }

  inline void markVoxel(unsigned int x, unsigned int y, unsigned int z)
  {
    if (x >= size_x_ || y >= size_y_ || z >= size_z_)
    {
      ROS_DEBUG("Error, voxel out of bounds.\n");
      return;
    }
    uint32_t full_mask = ((uint32_t)1<<z<<16) | (1<<z);
    data_[y * size_x_ + x] |= full_mask; //clear unknown and mark cell
  }

  inline bool markVoxelInMap(unsigned int x, unsigned int y, unsigned int z, unsigned int marked_threshold)
  {
    if (x >= size_x_ || y >= size_y_ || z >= size_z_)
    {
      ROS_DEBUG("Error, voxel out of bounds.\n");
      return false;
    }

    int index = y * size_x_ + x;
    uint32_t* col = &data_[index];
    uint32_t full_mask = ((uint32_t)1<<z<<16) | (1<<z);
    *col |= full_mask; //clear unknown and mark cell

    unsigned int marked_bits = *col>>16;

    //make sure the number of bits in each is below our thesholds
    return !bitsBelowThreshold(marked_bits, marked_threshold);
  }

  inline void clearVoxel(unsigned int x, unsigned int y, unsigned int z)
  {
    if (x >= size_x_ || y >= size_y_ || z >= size_z_)
    {
      ROS_DEBUG("Error, voxel out of bounds.\n");
      return;
    }
    uint32_t full_mask = ((uint32_t)1<<z<<16) | (1<<z);
    data_[y * size_x_ + x] &= ~(full_mask); //clear unknown and clear cell
  }

  inline void clearVoxelColumn(unsigned int index)
  {
    ROS_ASSERT(index < size_x_ * size_y_);
    data_[index] = 0;
  }

  inline void clearVoxelInMap(unsigned int x, unsigned int y, unsigned int z)
  {
    if(x >= size_x_ || y >= size_y_ || z >= size_z_)
    {
      ROS_DEBUG("Error, voxel out of bounds.\n");
      return;
    }
    int index = y * size_x_ + x;
    uint32_t* col = &data_[index];
    uint32_t full_mask = ((uint32_t)1<<z<<16) | (1<<z);
    *col &= ~(full_mask); //clear unknown and clear cell

    unsigned int unknown_bits = uint16_t(*col>>16) ^ uint16_t(*col);
    unsigned int marked_bits = *col>>16;

    //make sure the number of bits in each is below our thesholds
    if (bitsBelowThreshold(unknown_bits, 1) && bitsBelowThreshold(marked_bits, 1))
    {
      costmap[index] = 0;
    }
  }

  inline bool bitsBelowThreshold(unsigned int n, unsigned int bit_threshold)
  {
    unsigned int bit_count;
    for (bit_count = 0; n;)
    {
      ++bit_count;
      if (bit_count > bit_threshold)
      {
        return false;
      }
      n &= n - 1; //clear the least significant bit set
    }
    return true;
  }

  static inline unsigned int numBits(unsigned int n)
  {
    unsigned int bit_count;
    for (bit_count = 0; n; ++bit_count)
    {
      n &= n - 1; //clear the least significant bit set
    }
    return bit_count;
  }

  static VoxelStatus getVoxel(
    unsigned int x, unsigned int y, unsigned int z,
    unsigned int size_x, unsigned int size_y, unsigned int size_z, const uint32_t* data)
  {
    if (x >= size_x || y >= size_y || z >= size_z)
    {
      ROS_DEBUG("Error, voxel out of bounds. (%d, %d, %d)\n", x, y, z);
      return UNKNOWN;
    }
    uint32_t full_mask = ((uint32_t)1<<z<<16) | (1<<z);
    uint32_t result = data[y * size_x + x] & full_mask;
    unsigned int bits = numBits(result);

    // known marked: 11 = 2 bits, unknown: 01 = 1 bit, known free: 00 = 0 bits
    if (bits < 2)
    {
      if (bits < 1)
      {
        return FREE;
      }
      return UNKNOWN;
    }
    return MARKED;
  }

  void markVoxelLine(double x0, double y0, double z0, double x1, double y1, double z1, unsigned int max_length = UINT_MAX);
  void clearVoxelLine(double x0, double y0, double z0, double x1, double y1, double z1, unsigned int max_length = UINT_MAX);
  void clearVoxelLineInMap(double x0, double y0, double z0, double x1, double y1, double z1, unsigned char *map_2d,
                           unsigned int unknown_threshold, unsigned int mark_threshold,
                           unsigned char free_cost = 0, unsigned char unknown_cost = 255, unsigned int max_length = UINT_MAX);

  VoxelStatus getVoxel(unsigned int x, unsigned int y, unsigned int z);

  //Are there any obstacles at that (x, y) location in the grid?
  VoxelStatus getVoxelColumn(unsigned int x, unsigned int y,
                             unsigned int unknown_threshold = 0, unsigned int marked_threshold = 0);

  void printVoxelGrid();
  void printColumnGrid();
  unsigned int sizeX();
  unsigned int sizeY();
  unsigned int sizeZ();

  template <class ActionType>
  inline void raytraceLine(
    ActionType at, double x0, double y0, double z0,
    double x1, double y1, double z1, unsigned int max_length = UINT_MAX)
  {
    int dx = int(x1) - int(x0);
    int dy = int(y1) - int(y0);
    int dz = int(z1) - int(z0);

    unsigned int abs_dx = abs(dx);
    unsigned int abs_dy = abs(dy);
    unsigned int abs_dz = abs(dz);

    int offset_dx = sign(dx);
    int offset_dy = sign(dy) * size_x_;
    int offset_dz = sign(dz);

    unsigned int z_mask = ((1 << 16) | 1) << (unsigned int)z0;
    unsigned int offset = (unsigned int)y0 * size_x_ + (unsigned int)x0;

    GridOffset grid_off(offset);
    ZOffset z_off(z_mask);

    //we need to chose how much to scale our dominant dimension, based on the maximum length of the line
    double dist = sqrt((x0 - x1) * (x0 - x1) + (y0 - y1) * (y0 - y1) + (z0 - z1) * (z0 - z1));
    double scale = std::min(1.0,  max_length / dist);

    //is x dominant
    if (abs_dx >= max(abs_dy, abs_dz))
    {
      int error_y = abs_dx / 2;
      int error_z = abs_dx / 2;

      bresenham3D(at, grid_off, grid_off, z_off, abs_dx, abs_dy, abs_dz, error_y, error_z, offset_dx, offset_dy, offset_dz, offset, z_mask, (unsigned int)(scale * abs_dx));
      return;
    }

    //y is dominant
    if (abs_dy >= abs_dz)
    {
      int error_x = abs_dy / 2;
      int error_z = abs_dy / 2;

      bresenham3D(at, grid_off, grid_off, z_off, abs_dy, abs_dx, abs_dz, error_x, error_z, offset_dy, offset_dx, offset_dz, offset, z_mask, (unsigned int)(scale * abs_dy));
      return;
    }

    //otherwise, z is dominant
    int error_x = abs_dz / 2;
    int error_y = abs_dz / 2;

    bresenham3D(at, z_off, grid_off, grid_off, abs_dz, abs_dx, abs_dy, error_x, error_y, offset_dz, offset_dx, offset_dy, offset, z_mask, (unsigned int)(scale * abs_dz));
  }

private:
  //the real work is done here... 3D bresenham implementation
  template <class ActionType, class OffA, class OffB, class OffC>
  inline void bresenham3D(
    ActionType at, OffA off_a, OffB off_b, OffC off_c,
    unsigned int abs_da, unsigned int abs_db, unsigned int abs_dc,
    int error_b, int error_c, int offset_a, int offset_b, int offset_c, unsigned int &offset,
    unsigned int &z_mask, unsigned int max_length = UINT_MAX)
  {
    unsigned int end = std::min(max_length, abs_da);
    for (unsigned int i = 0; i < end; ++i)
    {
      at(offset, z_mask);
      off_a(offset_a);
      error_b += abs_db;
      error_c += abs_dc;
      if ((unsigned int)error_b >= abs_da)
      {
        off_b(offset_b);
        error_b -= abs_da;
      }
      if ((unsigned int)error_c >= abs_da)
      {
        off_c(offset_c);
        error_c -= abs_da;
      }
    }
    at(offset, z_mask);
  }

  inline int sign(int i)
  {
    return i > 0 ? 1 : -1;
  }

  inline unsigned int max(unsigned int x, unsigned int y)
  {
    return x > y ? x : y;
  }

  unsigned int size_x_, size_y_, size_z_;
  uint32_t *data_;
  unsigned char *costmap;

  //Aren't functors so much fun... used to recreate the Bresenham macro Eric wrote in the original version, but in "proper" c++
  class MarkVoxel
  {
  public:
    MarkVoxel(uint32_t* data): data_(data){}
    inline void operator()(unsigned int offset, unsigned int z_mask)
    {
      data_[offset] |= z_mask; //clear unknown and mark cell
    }
  private:
    uint32_t* data_;
  };

  class ClearVoxel
  {
  public:
    ClearVoxel(uint32_t* data): data_(data){}
    inline void operator()(unsigned int offset, unsigned int z_mask)
    {
      data_[offset] &= ~(z_mask); //clear unknown and clear cell
    }
  private:
    uint32_t* data_;
  };

  class ClearVoxelInMap
  {
  public:
    ClearVoxelInMap(
      uint32_t* data, unsigned char *costmap,
      unsigned int unknown_clear_threshold, unsigned int marked_clear_threshold,
      unsigned char free_cost = 0, unsigned char unknown_cost = 255): data_(data), costmap_(costmap),
      unknown_clear_threshold_(unknown_clear_threshold), marked_clear_threshold_(marked_clear_threshold),
      free_cost_(free_cost), unknown_cost_(unknown_cost)
    {
    }

    inline void operator()(unsigned int offset, unsigned int z_mask)
    {
      uint32_t* col = &data_[offset];
      *col &= ~(z_mask); //clear unknown and clear cell

      unsigned int unknown_bits = uint16_t(*col>>16) ^ uint16_t(*col);
      unsigned int marked_bits = *col>>16;

      //make sure the number of bits in each is below our thesholds
      if (bitsBelowThreshold(marked_bits, marked_clear_threshold_))
      {
        if (bitsBelowThreshold(unknown_bits, unknown_clear_threshold_))
        {
          costmap_[offset] = free_cost_;
        }
        else
        {
          costmap_[offset] = unknown_cost_;
        }
      }
    }
  private:
    inline bool bitsBelowThreshold(unsigned int n, unsigned int bit_threshold)
    {
      unsigned int bit_count;
      for (bit_count = 0; n;)
      {
        ++bit_count;
        if (bit_count > bit_threshold)
        {
          return false;
        }
        n &= n - 1; //clear the least significant bit set
      }
      return true;
    }

    uint32_t* data_;
    unsigned char *costmap_;
    unsigned int unknown_clear_threshold_, marked_clear_threshold_;
    unsigned char free_cost_, unknown_cost_;
  };

  class GridOffset
  {
  public:
    GridOffset(unsigned int &offset) : offset_(offset) {}
    inline void operator()(int offset_val)
    {
      offset_ += offset_val;
    }
  private:
    unsigned int &offset_;
  };

  class ZOffset
  {
  public:
    ZOffset(unsigned int &z_mask) : z_mask_(z_mask) {}
    inline void operator()(int offset_val)
    {
      offset_val > 0 ? z_mask_ <<= 1 : z_mask_ >>= 1;
    }
  private:
    unsigned int & z_mask_;
  };
};

}  // namespace voxel_grid

#endif  // VOXEL_GRID_VOXEL_GRID_H