Gazebo Common

API Reference

5.7.0
gz/common/geospatial/ImageHeightmap.hh
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4  * Licensed under the Apache License, Version 2.0 (the "License");
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17 #ifndef GZ_COMMON_GEOSPATIAL_IMAGEHEIGHTMAPDATA_HH_
18 #define GZ_COMMON_GEOSPATIAL_IMAGEHEIGHTMAPDATA_HH_
19 
20 #include <limits>
21 #include <string>
22 #include <vector>
23 #include <gz/math/Vector3.hh>
24 
25 #include <gz/common/geospatial/Export.hh>
27 #include <gz/common/Image.hh>
28 
29 namespace gz
30 {
31  namespace common
32  {
34  class GZ_COMMON_GEOSPATIAL_VISIBLE ImageHeightmap
36  {
39  public: ImageHeightmap();
40 
44  public: int Load(const std::string &_filename = "");
45 
46  // Documentation inherited.
47  public: void FillHeightMap(int _subSampling, unsigned int _vertSize,
48  const gz::math::Vector3d &_size,
49  const gz::math::Vector3d &_scale, bool _flipY,
50  std::vector<float> &_heights) const;
51 
52  // Documentation inherited.
53  public: std::string Filename() const;
54 
55  // Documentation inherited.
56  public: unsigned int Height() const;
57 
58  // Documentation inherited.
59  public: unsigned int Width() const;
60 
61  // Documentation inherited.
62  public: float MaxElevation() const;
63 
65  private: gz::common::Image img;
66 
77  private: template <typename T>
78  void FillHeights(T *_data, int _imgHeight, int _imgWidth,
79  unsigned int _pitch, int _subSampling, unsigned int _vertSize,
80  const gz::math::Vector3d &_size,
81  const gz::math::Vector3d &_scale,
82  bool _flipY, std::vector<float> &_heights) const
83  {
84  // bytes per pixel
85  const unsigned int bpp = _pitch / _imgWidth;
86  // number of channels in a pixel
87  const unsigned int channels = bpp / sizeof(T);
88  // number of pixels in a row of image
89  const unsigned int pitchInPixels = _pitch / bpp;
90 
91  const double maxPixelValue =
92  static_cast<double>(std::numeric_limits<T>::max());
93 
94  // Iterate over all the vertices
95  for (unsigned int y = 0; y < _vertSize; ++y)
96  {
97  // yf ranges between 0 and 4
98  const double yf = y / static_cast<double>(_subSampling);
99  const int y1 = static_cast<int>(std::floor(yf));
100  int y2 = static_cast<int>(std::ceil(yf));
101  if (y2 >= _imgHeight)
102  y2 = _imgHeight - 1;
103  const double dy = yf - y1;
104 
105  for (unsigned int x = 0; x < _vertSize; ++x)
106  {
107  const double xf = x / static_cast<double>(_subSampling);
108  const int x1 = static_cast<int>(std::floor(xf));
109  int x2 = static_cast<int>(std::ceil(xf));
110  if (x2 >= _imgWidth)
111  x2 = _imgWidth - 1;
112  const double dx = xf - x1;
113 
114  const double px1 = static_cast<int>(
115  _data[(y1 * pitchInPixels + x1) * channels]) / maxPixelValue;
116  const double px2 = static_cast<int>(
117  _data[(y1 * pitchInPixels + x2) * channels]) / maxPixelValue;
118  const float h1 = (px1 - ((px1 - px2) * dx));
119 
120  const double px3 = static_cast<int>(
121  _data[(y2 * pitchInPixels + x1) * channels]) / maxPixelValue;
122  const double px4 = static_cast<int>(
123  _data[(y2 * pitchInPixels + x2) * channels]) / maxPixelValue;
124  const float h2 = (px3 - ((px3 - px4) * dx));
125  float h = (h1 - ((h1 - h2) * dy)) * _scale.Z();
126 
127  // invert pixel definition so 1=ground, 0=full height,
128  // if the terrain size has a negative z component
129  // this is mainly for backward compatibility
130  if (_size.Z() < 0)
131  h = 1.0 - h;
132 
133  // Store the height for future use
134  if (!_flipY)
135  _heights[y * _vertSize + x] = h;
136  else
137  _heights[(_vertSize - y - 1) * _vertSize + x] = h;
138  }
139  }
140  }
141  };
142  }
143 }
144 #endif