2019년 4월 13일 토요일

# A* 길찾기 알고리즘 ( C++ )

매우 심플하게 만든 A* 알고리즘. 이전에 C#으로 만든걸 C++ 로 옴겨서 테스트용으로 작성했다. 
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#pragma once

#include "PathNode.h"
#include <vector>
#include <stack>
using namespace std;

#define MAP_SIZE_X 10
#define MAP_SIZE_Y 10

class CustomAStar
{
public:
 CustomAStar();
 ~CustomAStar();
 
 void SetGoalNode(int x, int y);
 //길찾기를 시작합니다. ( 시작 노드 위치를 인자로 설정.)
 stack<PathNode*>* PathFinding(int x, int y);
 // 장애물을 지정합니다.
 void SetObstacle(int x, int y);
private:
 PathNode* pathMap[MAP_SIZE_X][MAP_SIZE_Y];
 vector<PathNode*> openList;
 vector<PathNode*> closedList;
 vector<Vector2> fourDir;
 stack<PathNode*> navigatePath;
 PathNode* curNode;
 PathNode* goalNode;

 void InitMap();
 void InitPathFinding();
 void CurNodeToClosedList();
 bool IsInClosedList(int searchPosX, int searchPosY);
 bool IsInOpenList(int searchPosX, int searchPosY);
 bool IsGoalInOpenList();
 void SetOpenList();
 void SearchAdjacentNodes(PathNode* selectNode);
 void ExtractNavigatePath();
 void SetStartNode(int x, int y);
 
 PathNode* SelectLowCostPath();
};

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#include "CustomAStar.h"



CustomAStar::CustomAStar()
{
 fourDir.push_back(Vector2(0, 1));
 fourDir.push_back(Vector2(0, -1));
 fourDir.push_back(Vector2(-1, 0));
 fourDir.push_back(Vector2(1, 0));

 InitMap();
}


CustomAStar::~CustomAStar()
{
}
void CustomAStar::SetStartNode(int x, int y)
{
 curNode = pathMap[x][y];
 curNode->SetParentNode(nullptr);
 curNode->CalcHValue(goalNode);
 openList.push_back(curNode);
}
void CustomAStar::SetGoalNode(int x, int y)
{
 goalNode = pathMap[x][y];
 goalNode->isGoalNode = true;
}
stack<PathNode*>* CustomAStar::PathFinding(int x, int y)
{
 InitPathFinding();
 SetStartNode(x, y);
 while ((openList.size() != 0) && (!IsGoalInOpenList()))
 {
  SetOpenList();
  PathNode* selectNode = SelectLowCostPath();
  if (selectNode != nullptr) SearchAdjacentNodes(selectNode);
 }
 ExtractNavigatePath();
 return &navigatePath;
}
void CustomAStar::SetObstacle(int x, int y)
{
 closedList.push_back(pathMap[x][y]);
}
// pathMap을 초기화 합니다.
void CustomAStar::InitMap()
{
 for(int x = 0; x < MAP_SIZE_X; x++)
  for (int y = 0; y < MAP_SIZE_Y; y++) {
   PathNode* node = new PathNode();
   node->SetPosition(x, y);
   pathMap[x][y] = node;
   pathMap[x][y]->isGoalNode = false;
  }
}
// 길찾기 전에 호출되어 초기화를 진행합니다.
void CustomAStar::InitPathFinding()
{
 openList.clear();
 closedList.clear();
}

void CustomAStar::CurNodeToClosedList()
{
 closedList.push_back(curNode);

 vector<PathNode*>::iterator it = openList.begin();
 while (it != openList.end()) {
  if ((*it)->GetPosition() == curNode->GetPosition()) {
   openList.erase(it);
   break;
  }
  it++;
 }
}

bool CustomAStar::IsInClosedList(int searchPosX, int searchPosY)
{
 bool isFind = false;
 for each (auto node in closedList){
  if ((node->GetPosition().x == searchPosX) &&
   (node->GetPosition().y == searchPosY))
   isFind = true;
 }
 return isFind;
}

bool CustomAStar::IsInOpenList(int searchPosX, int searchPosY)
{
 bool isFind = false;
 for each (auto node in openList){
  if ((node->GetPosition().x == searchPosX) &&
   (node->GetPosition().y == searchPosY))
   isFind = true;
 }
 return isFind;
}

bool CustomAStar::IsGoalInOpenList()
{
 bool isFind = false;
 for each (auto node in openList) {
  if (node->isGoalNode)
   isFind = true;
 }
 return isFind;
}

void CustomAStar::SetOpenList()
{
 for each(Vector2 pos in fourDir){
  int searchPosX = curNode->GetPosition().x + pos.x;
  int searchPosY = curNode->GetPosition().y + pos.y;
  if ((searchPosX >= 0 && searchPosX < MAP_SIZE_X) && (searchPosY >= 0 && searchPosY < MAP_SIZE_Y)){
   if ((!IsInClosedList(searchPosX, searchPosY)) && (!IsInOpenList(searchPosX, searchPosY))){
    pathMap[searchPosX][searchPosY]->SetParentNode(curNode);
    pathMap[searchPosX][searchPosY]->CalcHValue(goalNode);
    pathMap[searchPosX][searchPosY]->CalcGValue();
    openList.push_back(pathMap[searchPosX][searchPosY]);
   }
  }
 }
 CurNodeToClosedList();
}

void CustomAStar::SearchAdjacentNodes(PathNode * selectNode)
{
 for each(Vector2 pos in fourDir){
  int searchPosX = selectNode->GetPosition().x;
  int searchPosY = selectNode->GetPosition().y;
  if ((searchPosX >= 0 && searchPosX < MAP_SIZE_X) && (searchPosY >= 0 && searchPosY < MAP_SIZE_Y)){
   if (!IsInClosedList(searchPosX, searchPosY)){
    if (!IsInOpenList(searchPosX, searchPosY)){
     openList.push_back(pathMap[searchPosX][searchPosY]);
     pathMap[searchPosX][searchPosY]->SetParentNode(curNode);
     pathMap[searchPosX][searchPosY]->CalcHValue(goalNode);
     pathMap[searchPosX][searchPosY]->CalcGValue();
    }
    else{
     if ((pathMap[searchPosX][searchPosY]->GetGValue() < selectNode->GetGValue())){
      selectNode->SetParentNode(pathMap[searchPosX][searchPosY]);
      selectNode->CalcHValue(goalNode);
      selectNode->CalcGValue();
     }
    }
   }

  }
 }
}

void CustomAStar::ExtractNavigatePath()
{
 PathNode* path = goalNode;
 while (path->GetParentNode() != nullptr){
  navigatePath.push(path);
  path = path->GetParentNode();
 }
}

PathNode* CustomAStar::SelectLowCostPath()
{
 int minCost = 0;
 PathNode* lowCostPath = nullptr;
 if (openList.empty()) return nullptr;

 minCost = openList[0]->GetGValue() + openList[0]->GetHValue();
 lowCostPath = openList[0];
 for (int i = 1; i < openList.size(); i++){
  int cost = openList[i]->GetGValue() + openList[i]->GetHValue();
  if (minCost > cost){
   minCost = cost;
   lowCostPath = openList[i];
  }
 }

 vector<PathNode*>::iterator it = openList.begin();
 while (it != openList.end()) {
  if ((*it)->GetPosition() == lowCostPath->GetPosition()) {
   openList.erase(it);
   break;
  }
  it++;
 }
 closedList.push_back(lowCostPath);
 curNode = lowCostPath;
 
 return lowCostPath;
}

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#pragma once
#include <math.h>
struct Vector2
{
public:
 int x;
 int y;
 Vector2(int _x, int _y) {
  x = _x;
  y = _y;
 }
 Vector2() {
  // 디폴트.
 }
 bool operator ==(const Vector2& vec) const {
  if ((x == vec.x) && (y == vec.y)) return true;
  else return false;
 }
};

class PathNode
{
public:
 PathNode();
 ~PathNode();
 
 void CalcGValue();
 void CalcHValue(PathNode* goal);
 Vector2 GetPosition();
 void SetPosition(int x, int y);
 void SetPosition(Vector2 pos);
 PathNode* GetParentNode();
 int GetGValue();
 int GetHValue();
 void SetParentNode(PathNode* node);

 bool isGoalNode;
private:
 PathNode* parentNode = nullptr;
 int gValue = 0;
 int hValue = 0;
 Vector2 position;

};

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#include "PathNode.h"



PathNode::PathNode()
{
}


PathNode::~PathNode()
{
}

void PathNode::CalcGValue()
{
 if (parentNode == nullptr) {
  gValue = 0;
  return;
 }
 int diffX = position.x - parentNode->GetPosition().x;
 int diffY = position.y - parentNode->GetPosition().y;
 if (((diffX == -1) && (diffY == 1))
  || ((diffX == 1) && (diffY == 1))
  || ((diffX == -1) && (diffY == -1))
  || ((diffX == 1) && (diffY == -1))){
  gValue = (abs(diffX) + abs(diffY)) * 14 + parentNode->GetGValue();
 }
 else{
  gValue = (abs(diffX) + abs(diffY)) * 10 + parentNode->GetGValue();
 }
}

void PathNode::CalcHValue(PathNode* goal)
{
 int diffX = goal->GetPosition().x - position.x;
 int diffY = goal->GetPosition().y - position.y;
 
 hValue = (abs(diffX) + abs(diffY)) * 10;
}

Vector2 PathNode::GetPosition()
{
 return position;
}

void PathNode::SetPosition(int x, int y)
{
 position.x = x;
 position.y = y;
}

void PathNode::SetPosition(Vector2 pos)
{
 position = pos;
}

PathNode* PathNode::GetParentNode()
{
 return parentNode;
}

int PathNode::GetGValue()
{
 return gValue;
}

int PathNode::GetHValue()
{
 return hValue;
}

void PathNode::SetParentNode(PathNode * node)
{
 parentNode = node;
}
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