tepatch.cpp

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: TePatch.cpp 28 2005-08-28 10:37:47Z peciva $

/*****************************************************************************\
 *
 * TePatch.cpp
 *
 * TePatch - terrain patch class
 *
 * Author: PCJohn (peciva AT fit.vutbr.cz)
 * Contributors: Martin Havl龛ek (xhavli15 AT stud.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.
 *
\*****************************************************************************/


#include <Inventor/nodes/SoCoordinate3.h>
#include <Inventor/nodes/SoIndexedTriangleStripSet.h>
#include <Inventor/nodes/SoMaterial.h>
#include <Inventor/nodes/SoMaterialBinding.h>
#include <Inventor/nodes/SoNormal.h>
#include <Inventor/nodes/SoNormalBinding.h>
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/nodes/SoTranslation.h>
#include <Inventor/errors/SoDebugError.h>

#include <ctime>

#include "TePatch.h"
#include "TeHeightMap.h"
#include "TeEngine.h"


//-----------------------------------------------------------------------------
/**
 * Simple default constructor.
 *
 * It does not specify the engine that manages this patch and therefore is
 * private and shoul be \b never called. Documented only to explain the
 * reason.
 */
TePatch::TePatch()
{
  assert(0 && "Default constructor of TePatch is private and should be never called.");
}


//-----------------------------------------------------------------------------
/**
 * Constructor.
 *
 * \param aengine Engine in which patch hierarchy this patch belongs.
 */
TePatch::TePatch(TeEngine *aengine) : hmap(NULL), engine(aengine), parent(NULL), graph(NULL)
{
  assert(engine && "Engine parameter can not be NULL.");
  int i;
  for (i=0;i<8;i++)  seamMap[i] = NULL;
  for (i=0;i<4;i++)  buildMap[i] = NULL;
  for (i=0;i<4;i++)  detail[i] = NULL;
  for (i=0;i<8;i++)  neighbour[i] = NULL;
  for (i=0;i<8;i++)  seamGraph[i] = NULL;
}


//-----------------------------------------------------------------------------
/**
 * Destructor.
 *
 * Releases memory.
 *
 * \todo Cancel scheduled tasks at engine. ???
 */
TePatch::~TePatch()
{
  int i;

  // TODO: cancel scheduled tasks at engine

  // delete more detail patches
  for (i=0; i<4; i++)  delete detail[i];

  // delete buildMaps
  if (!neighbour[SOUTH_WEST] && !neighbour[SOUTH] && !neighbour[WEST])  delete buildMap[SOUTH_WEST];
  if (!neighbour[SOUTH_EAST] && !neighbour[SOUTH] && !neighbour[EAST])  delete buildMap[SOUTH_EAST];
  if (!neighbour[NORTH_WEST] && !neighbour[NORTH] && !neighbour[WEST])  delete buildMap[NORTH_WEST];
  if (!neighbour[NORTH_EAST] && !neighbour[NORTH] && !neighbour[EAST])  delete buildMap[NORTH_EAST];

  // release heightmap
  delete hmap;

  // release seam height maps
  for (i=0; i<8; i++)  delete seamMap[i];

  // release scene graphs
  if (graph)  graph->unref();
  for (i=0; i<8; i++)
    if (seamGraph[i])  seamGraph[i]->unref();

  // remove self from neighbours references
  for (i=0; i<8; i++)
    if (neighbour[i]) {
      neighbour[i]->neighbour[getOppositeDirection(i)] = NULL;
    }

  // remove parent reference
  if (parent) { // this is always true if we are not root node
    for (i=0; i<4; i++) {
      if (parent->detail[i] == this) {
        parent->detail[i] = NULL;
        break;
      }
    }
    assert(i<4 && "This patch was not found in the parent patch!");
  }
  else
    if (engine->getRootPatch() == this)
      engine->onRootDestroy();
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \return Const pointer to the patch heightmap.
 *
 * \sa hmap, setHMap()
 */
const TeHeightMap* TePatch::getHMap() const
{
  return hmap;
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \return Pointer to the patch heightmap.
 *
 * \sa hmap, setHMap()
 */
TeHeightMap* TePatch::getHMap()
{
  return hmap;
}


//-----------------------------------------------------------------------------
/**
 * Sets private hmap attribute.
 *
 * This function checks if the resolution of the heightmap \a hmap is the same
 * as the one set in the engine. If it is not so, nothing happens and the
 * warning is post. If there is already some heightmap set, it is deleted.
 *
 * \param hmap Pointer to the heightmap.
 *
 * \todo When the heightmap is being deleted, we probably should unref all
 *       scene graphs and delete the seam maps too.
 *
 * \sa hmap, getHMap()
 */
void TePatch::setHMap(TeHeightMap *hmap)
{
  if (hmap->getResolution() != engine->getHMapResolution()) {
    SoDebugError::post("TePatch:setHMap",
                       "HMap resolution must be the same as the one set in TeEngine constructor,\n"
                       "that usually defaults to 65x65. The problem is handled by ignoring of this call.");
    return;
  }

  if (this->hmap)
    delete this->hmap;

  this->hmap = hmap;
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \param which Seam map selector.
 * \return Const pointer to the specified seam map.
 *
 * \sa seamMap, setSeamMap()
 */
const TeHeightMap* TePatch::getSeamMap(const Direction which) const
{
  assert(which>=0 && which<8 && "Wrong which parameter.");
  return seamMap[which];
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \param which Seam map selector.
 * \return Pointer to the specified seam map.
 *
 * \sa seamMap, setSeamMap()
 */
TeHeightMap* TePatch::getSeamMap(const Direction which)
{
  assert(which>=0 && which<8 && "Wrong which parameter.");
  return seamMap[which];
}


//-----------------------------------------------------------------------------
/**
 * Sets private seam map attribute.
 *
 * This function checks if the resolution of the heightmap \a map corresponds
 * with the one set in the engine and the selected seam. If it is not so,
 * nothing happens and the warning is post.
 *
 * \param which Seam map selector.
 * \param map Pointer to the heightmap.
 *
 * \sa seamMap, getSeamMap()
 *
 * \todo If there is already some seam map set, it should be deleted. It is
 *       similar to the TePatch::setHMap() function.
 */
void TePatch::setSeamMap(const Direction which, TeHeightMap *map)
{
  assert(which>=0 && which<8 && "Wrong which parameter.");

  int rx,ry;
  map->getResolution(rx,ry);
  if (which < 4) {
    if (rx != 5 || ry != 5)  goto bad_res;
  }
  else {
    const SbVec2s &res = engine->getHMapResolution();
    if (which == WEST || which == EAST) {
      if (rx != 5 || ry != res[1])  goto bad_res;
    } else {
      if (ry != 5 || rx != res[0])  goto bad_res;
    }
  }


  seamMap[which] = map;
  return;

bad_res:
  SoDebugError::post("TePatch:setSeamMap",
                     "Wrong seam height maps resolution. It must be [5,TeEngine::\n"
                     "getHMapResolution()[1], or [TeEngine::getHMapResolution()[0],5],\n"
                     "or [5,5], depending of which parameter. Setting of the height map is ignored.");
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \return Pointer to the attached engine.
 *
 * \sa engine, setEngine()
 */
TeEngine* TePatch::getEngine() const
{
  return engine;
}


//-----------------------------------------------------------------------------
/**
 * Should set the private engine attribute.
 *
 * This function is not implemented yet, it looks like we don't need it...
 *
 * \sa engine, getEngine()
 *
 * \todo Not implemented yet. Consider removing it completely, because its
 *       work is done in constructor and changing attached engines at
 *       run-time will be strange hack.
 */
void TePatch::setEngine()
{
  assert(0 && "Not implemented yet.");
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \return Rectangle area occupied by the scene graph.
 *
 * \sa area
 */
const SbBox2f& TePatch::getArea() const
{
  return area;
}


//-----------------------------------------------------------------------------
/**
 * Gets level of the patch in the hierarchy.
 *
 * \return Patch level in the hierarchy.
 *
 * \todo More detailed documentation.
 */
int TePatch::getLevel() const
{
  if (parent)
    return parent->getLevel() - 1;
  else
    if (engine->getRootPatch() == this)  return engine->getRootLevel();
    else {
      SoDebugError::post("TePatch::getLevel",
                         "It is forbidden to call getLevel() until TePatch is made part of the\n"
                         "TePatch hierarchy headed by an TeEngine.");
      return 0;
    }
}


//-----------------------------------------------------------------------------
/**
 * Private attribute accessor.
 *
 * \return Parent patch in the hierarchy.
 *
 * \sa parent
 *
 * \todo More detailed documentation.
 */
TePatch* TePatch::getParent() const
{
  return parent;
}


//-----------------------------------------------------------------------------
/**
 * Documentation not available.
 *
 * \todo More detailed documentation.
 */
TePatch* TePatch::getPatchHierarch(const SbVec2f &pos, const int level, PatchMissedPolicy policy)
{
  return getPatchHierarchRelative(pos, level - this->getLevel(), policy);
}


//-----------------------------------------------------------------------------
/**
 * Documentation not available.
 *
 * \todo More detailed documentation.
 */
TePatch* TePatch::getPatchHierarchRelative(const SbVec2f &pos, const int relativeLevel, PatchMissedPolicy policy)
{
  // policy works like this:
  //   - DONT_CREATE  - return NULL
  //   - CREATE       - create all necesary patches
  //   - LOWER_DETAIL - return patch matching pos, but possible with lower detail
  //                    than specified. If pos falls outside the current patch root,
  //                    new nodes are appended to the top of patch tree to match pos.


  // handle requests for higher level
  if (relativeLevel > 0)
    if (parent)  return parent->getPatchHierarchRelative(pos, relativeLevel-1, policy);
    else {
      if (!engine) {
        SoDebugError::post("TePatch::getPatchHierarchRelative",
                           "The patch must be appended to the TePatch tree\n"
                           "before the call of this function.");
        return NULL;