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A star

Pelayo M · 2013-01-27T18:09:52

I have this A* code, but I am desperate, it keeps giving me errors and I have no idea about what is going on. The code is quite big, but I can post the build errors so you guys can spot where the problems are; I'm not sure if anyone can help, as to help, one needs to be an ace at this. Build errors: In function 'std::string pathFind(const int&, const int&, const int&, const int&)':| |156|error: reference to 'map' is ambiguous| |16|error: candidates are: int map [60][60]| c:\program files (x86)\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.4.1\include\c++\bits\stl_map.h|86|error: template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map| |156|error: reference to 'map' is ambiguous| |16|error: candidates are: int map [60][60]| c:\program files (x86)\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.4.1\include\c++\bits\stl_map.h|86|error: template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map| |93|warning: unused variable 'xdx'| |93|warning: unused variable 'ydy'| ||=== Build finished: 6 errors, 2 warnings ===| #include <iostream> #include <iomanip> #include <queue> #include <string> #include <math.h> #include <ctime> #include "include.h" using namespace std; const int n=60; // horizontal size of the map const int m=60; // vertical size size of the map int map[n][m]; static int closed_nodes_map[n][m]; // map of closed (tried-out) nodes static int open_nodes_map[n][m]; // map of open (not-yet-tried) nodes static int dir_map[n][m]; // map of directions const int dir=8; // number of possible directions to go at any position // if dir==4 //static int dx[dir]={1, 0, -1, 0}; //static int dy[dir]={0, 1, 0, -1}; // if dir==8 static int dx[dir]={1, 1, 0, -1, -1, -1, 0, 1}; static int dy[dir]={0, 1, 1, 1, 0, -1, -1, -1}; class node { // current position int xPos; int yPos; // total distance already travelled to reach the node int level; // priority=level+remaining distance estimate int priority; // smaller: higher priority public: node(int xp, int yp, int d, int p) {xPos=xp; yPos=yp; level=d; priority=p;} int getxPos() const {return xPos;} int getyPos() const {return yPos;} int getLevel() const {return level;} int getPriority() const {return priority;} void updatePriority(const int & xDest, const int & yDest) { priority=level+estimate(xDest, yDest)*10; //A* } // give better priority to going strait instead of diagonally void nextLevel(const int & i) // i: direction { level+=(dir==8?(i%2==0?10:14):10); } // Estimation function for the remaining distance to the goal. const int & estimate(const int & xDest, const int & yDest) const { static int xd, yd, d; xd=xDest-xPos; yd=yDest-yPos; // Euclidian Distance d=static_cast<int>(sqrt(xd*xd+yd*yd)); // Manhattan distance //d=abs(xd)+abs(yd); // Chebyshev distance //d=max(abs(xd), abs(yd)); return(d); } }; // Determine priority (in the priority queue) bool operator<(const node & a, const node & b) { return a.getPriority() > b.getPriority(); } // A-star algorithm. // The route returned is a string of direction digits. string pathFind( const int & xStart, const int & yStart, const int & xFinish, const int & yFinish ) { static priority_queue<node> pq[2]; // list of open (not-yet-tried) nodes static int pqi; // pq index static node* n0; static node* m0; static int i, j, x, y, xdx, ydy; static char c; pqi=0; // reset the node maps for(y=0;y<m;y++) { for(x=0;x<n;x++) { closed_nodes_map[x][y]=0; open_nodes_map[x][y]=0; } } // create the start node and push into list of open nodes n0=new node(xStart, yStart, 0, 0); n0->updatePriority(xFinish, yFinish); pq[pqi].push(*n0); open_nodes_map[x][y]=n0->getPriority(); // mark it on the open nodes map // A* search while(!pq[pqi].empty()) { // get the current node w/ the highest priority // from the list of open nodes n0=new node( pq[pqi].top().getxPos(), pq[pqi].top().getyPos(), pq[pqi].top().getLevel(), pq[pqi].top().getPriority()); x=n0->getxPos(); y=n0->getyPos(); pq[pqi].pop(); // remove the node from the open list open_nodes_map[x][y]=0; // mark it on the closed nodes map closed_nodes_map[x][y]=1; // quit searching when the goal state is reached //if((*n0).estimate(xFinish, yFinish) == 0) if(x==xFinish && y==yFinish) { // generate the path from finish to start // by following the directions string path=""; while(!(x==xStart && y==yStart)) { j=dir_map[x][y]; c='0'+(j+dir/2)%dir; path=c+path; x+=dx[j]; y+=dy[j]; } // garbage collection delete n0; // empty the leftover nodes while(!pq[pqi].empty()) pq[pqi].pop(); return path; } // generate moves (child nodes) in all possible directions for(i=0;i<dir;i++) { int xdx = x+dx[i]; int ydy=y+dy[i]; if(!(xdx<0 || xdx>n-1 || ydy<0 || ydy>m-1 || map[xdx][ydy]==1 || closed_nodes_map[xdx][ydy]== 1)) { // generate a child node m0=new node( xdx, ydy, n0->getLevel(), n0->getPriority()); m0->nextLevel(i); m0->updatePriority(xFinish, yFinish); // if it is not in the open list then add into that if(open_nodes_map[xdx][ydy]==0) { open_nodes_map[xdx][ydy]=m0->getPriority(); pq[pqi].push(*m0); // mark its parent node direction dir_map[xdx][ydy]=(i+dir/2)%dir; } else if(open_nodes_map[xdx][ydy]>m0->getPriority()) { // update the priority info open_nodes_map[xdx][ydy]=m0->getPriority(); // update the parent direction info dir_map[xdx][ydy]=(i+dir/2)%dir; // replace the node // by emptying one pq to the other one // except the node to be replaced will be ignored // and the new node will be pushed in instead while(!(pq[pqi].top().getxPos()==xdx && pq[pqi].top().getyPos()==ydy)) { pq[1-pqi].push(pq[pqi].top()); pq[pqi].pop(); } pq[pqi].pop(); // remove the wanted node // empty the larger size pq to the smaller one if(pq[pqi].size()>pq[1-pqi].size()) pqi=1-pqi; while(!pq[pqi].empty()) { pq[1-pqi].push(pq[pqi].top()); pq[pqi].pop(); } pqi=1-pqi; pq[pqi].push(*m0); // add the better node instead } else delete m0; // garbage collection } } delete n0; // garbage collection } return ""; // no route found }

General and Gameplay Programming Programming

Started by mypel16000 January 22, 2013 09:38 PM

20 comments, last by Chad Smith 11 years, 2 months ago

Trienco

2,555

January 27, 2013 04:05 PM

I can pretty much promise you that the problem is with your code

Well, considering his new thread about this very issue ( http://www.gamedev.net/topic/637918-a-star-tutorials-sfml/ ), I don't think the problem is in "his" code, because apparently all he did so far is copy/paste some seriously awful code from the internet, include the .cpp in another .cpp, be confused about it not working and then asking for someone to do all the programming for him.

Okay, technically it still is in his code, considering that "include <Astar.cpp>" was most certainly not in the original code. Still, this looks like yet another case of wanting to write a game without first learning the absolute basics of the chosen language.

f@dzhttp://festini.device-zero.de

Chad Smith

1,344

January 27, 2013 06:09 PM

I/we can get your previous code to compile just fine using the exact instructions that had been given previously. I even went out of my way to download and install Code::Blocks to test it out so I can show you that it is not a Code::Blocks issue.

Your biggest issue though is that you're just not ready for this. I am pretty sure every programmer at some point has been there before. Bit off more then they can chew. I have done it multiple times and it hurt me. Just take your time learning the language. Every single feature you learn in the language make some VERY simple projects using those features to test it out. The more you code on your own the more you will understand what exactly the code is doing before you even run it. When you need help understanding something we will gladly help you and give you some ideas. We aren't going to write your code for you and you telling us "I just want a premade solution that I can just plug into my code" will get you people that don't want to help you.

The fact you copied and pasted this code and expected it to work is a red flag to us. You can't do that. Could you tell us what what your code is doing actually right now? You don't need it to compile for you to get a good idea on what will happen. Just follow your code line by line.

We do want to help you as this is what this community is for. Though we aren't just going to give you all the answers to your program and write all your code for you. Again we see you tried to include a .cpp file, that was a huge red flag for us even more to see that you aren't ready for this.

here is a quick lesson in working with multiple files.

Lets say you have the following class:


class Foo
{
public:
     Foo();
     
     int GetX();

private:
     int x;
};

What should we do with this class? We should put it in a header file. Though if we just did that and started including it with no include guards then we would be in trouble. We would be getting compiler errors galore! So what do we do to stop that? We use include guards

Foo.h


// The first thing you need to do in header files is use include guards
#ifndef FOO_H_ // It's just common to name it like this.  it doesn't HAVE to be like that
#define FOO_H_ // make sure you do use the same name though for no own.

class Foo
{
public:
     Foo();
     
     int GetX();

private:
     int x;
};

// Ok, now after your class and code that belongs in a header file you need a #endif
#endif //Your header file now has include guards  Include this header file when you need to use it.

Lets say you want to write the implementation details for the Foo Class. You need to do that in it's separate .cpp file (also called source files). First is first, you include the Foo.h header file then implement your class. You do not use include guards .cpp files. Only in header files.

Now you're ready to use this anywhere. When ever you need to use the Foo class you would just include Foo.h. That easy.

Just slow down what you want to do and start from the basics to learn the language. Sadly we can't go out and make the next biggest game without knowing how to use the language.

Again, we want to help you, but we can't just give your all your code nor can you expect to just find your code online and use it that way.

A star

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A star

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