teheightmap.h

海量地形数据漫游系统,对于OPENGL开发人员具有一定的参考

//##################################################
//# $Id: TeHeightMap.h 28 2005-08-28 10:37:47Z peciva $

#ifndef TE_HEIGHT_MAP_H
#define TE_HEIGHT_MAP_H

/*****************************************************************************\
 *
 * TeHeightMap.h
 *
 * TeHeightMap - height map class
 *
 * Author: Martin Havl龛ek (xhavli15 AT stud.fit.vutbr.cz)
 * Contributors: PCJohn (peciva AT fit.vutbr.cz)
 *
 * ----------------------------------------------------------------------------
 *
 * THIS SOFTWARE IS NOT COPYRIGHTED
 *
 * This source code is offered for use in the public domain.
 * You may use, modify or distribute it freely.
 *
 * This source code is distributed in the hope that it will be useful but
 * WITHOUT ANY WARRANTY.  ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
 * DISCLAIMED.  This includes but is not limited to warranties of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * If you find the source code useful, authors will kindly welcome
 * if you give them credit and keep their names with their source code.
 *
\*****************************************************************************/

/**
 * TeHeightMap class header file.
 *
 * \file TeHeightMap.h
 * \author Martin Havl龛ek (martyn AT seznam.cz)
 * \author PCJohn (peciva AT fit.vutbr.cz)
 */

#include <Inventor/SbLinear.h>

/**
 * Height map representation.
 *
 * This class provides many methods that cover all relevant operations
 * that can be done with heightmap values.
 *
 * The methods can be devided into several categories:
 * \li Set of constructors - these provide variety of ways how to initialize
 *     the heightmap object.
 * \li Size management - change resolution of the map without loosing values.
 * \li Setting, getting and copying values.
 * \li Statistics gathering - minimal, maximal and average height.
 * \li Vertical shifts.
 * \li Algebraic operations.
 * \li Generating values and their filtering.
 */
class TeHeightMap {

  friend class TeFaultFormation;
  friend class TeLinearFilter;

private:

  /** Heightmap x size. \sa getResolution(), setResolution() */
  int resx;
  /** Heightmap y size. \sa getResolution(), setResolution() */
  int resy;

  /** Array to store heightmap values. \sa getValues(), startEditing() */
  float *values;

  /** Minimal height storage \sa getMinValue(), getStats() */
  float minValue;
  /** Maximal height storage \sa getMaxValue(), getStats() */
  float maxValue;
  /** Average height storage \sa getAverageValue(), getStats() */
  float averageValue;

  /** Bitfield to store flags that indicates which statistics are valid. \sa resetFlags(), minValue, maxValue, averageValue */
  struct {
    unsigned int     minUpdated : 1; // bit 0
    unsigned int     maxUpdated : 1; // bit 1
    unsigned int averageUpdated : 1; // bit 2
    // free                          // ...
    // free                          // bit 31
  } flags;

  void resetFlags();

public:

  // Constructors
  TeHeightMap();
  TeHeightMap(const SbVec2s resolution);
  TeHeightMap(const int resx, const int resy);
  TeHeightMap(const TeHeightMap &hmap);
  TeHeightMap(const TeHeightMap *hmap, const SbVec2s origin, const SbVec2s size);

  // Destructor
  ~TeHeightMap();

  // Operators
  TeHeightMap& operator= (const TeHeightMap &hmap);

  // Heightmap size management
  SbVec2s getResolution() const;
  void getResolution(int &x, int &y) const;
  void setResolution(const SbVec2s &newRes);

  // Setting values
  void setValue(const int x, const int y, const float value);
  void setAllValues(const float value);

  // Getting values
  float getValue(const int x, const int y) const;
  const float* getValues() const;
  const float* operator[] (int i) const;
  float* startEditing();
  void finishEditing();

  // Statistics
  void getStats(float *min, float *max, float *average); // 1 pass
  float getMinValue();
  float getMaxValue();
  float getAverageValue();

  // Shifts
  void shift(const float delta);
  void shiftMinValue(const float value);
  void shiftMinValue(const float value, const float old);
  void shiftMaxValue(const float value);
  void shiftMaxValue(const float value, const float old);
  void shiftAverageValue(const float value);
  void shiftAverageValue(const float value, const float old);

  // Copying
  void copyFrom(const TeHeightMap *hmap);
  void copyFrom(const TeHeightMap *hmap, const SbVec2s &sorigin,
                const SbVec2s &size, const SbVec2s &dorigin = SbVec2s(0,0));

  // Adding (with rate, 1.0==100%)
  void addFrom(const TeHeightMap *hmap, const float rate);
  void addFrom(const TeHeightMap *hmap, const SbVec2s &sorigin,
               const SbVec2s &size, const SbVec2s &dorigin,
               const float rate);
  void addAll(const float value);

  // Subtracting (with rate, 1.0==100%)
  void subtractFrom(const TeHeightMap *hmap, const float rate);
  void subtractFrom(const TeHeightMap *hmap, const SbVec2s &sorigin,
                    const SbVec2s &size, const SbVec2s &dorigin,
                    const float rate);
  void subtractAll(const float value);

  // Multiplying (with rate, 1.0==100%)
  void multiplyFrom(const TeHeightMap *hmap, const float rate);
  void multiplyFrom(const TeHeightMap *hmap, const SbVec2s &sorigin,
                    const SbVec2s &size, const SbVec2s &dorigin,
                    const float rate);
  void multiplyAll(const float value);

  // Filtering
  void filter_Linear(const float coef, const int times);
  // ... more to come ...

  // Generating
  void generate_FaultFormation(const unsigned int seed, const int num_faults,
                               const float min_delta, const float max_delta);
  void generate_4HMOverlap_Mask();
  // ... more to come ...

  // FOR DEBUGGING ONLY
  void dump();

};

#endif /* TE_HEIGHT_MAP_H */