Issue with the SDL IMG_Load() function

[freakypanda]

Hello!
First of all, thanks to everyone who's reading my post and wants to help.
As the title says, I have a problem with the SDL IMG_Load() function.

In my code, I'm using the GetOpenFileName() function to get the absolute path of a file that is containing the path of an image that I will apply to a SDL_Surface with the IMG_Load() function. But it fails and I don't know why...

I tried to load the image directly by giving the relative (and absolute) path of the image and it works fine.

I also tried to directly open a file by giving the path of the file, get the path of the image and apply it to the SDL_Surface and it works fine too.

It only fails when I get the file path with the GetOpenFileName() function...

Here is the different functions I use to try to load the image :

bool CApp::OpenF(){
    FILE* FileHandle;
    char* FileName;

    //Useful stuff to correctly load the GetOpenFileName() function
    OPENFILENAME ofn;
    char szFile[260];
    HWND hwnd = NULL;
    ZeroMemory(&ofn, sizeof(ofn));
    ofn.lStructSize = sizeof(ofn);
    ofn.hwndOwner = hwnd;
    ofn.lpstrFile = szFile;
    ofn.lpstrFile[0] = '\0';
    ofn.nMaxFile = sizeof(szFile);
    ofn.lpstrFilter = "All\0*.*\0Text\0*.TXT\0";
    ofn.nFilterIndex = 1;
    ofn.lpstrFileTitle = NULL;
    ofn.nMaxFileTitle = 0;
    ofn.lpstrInitialDir = NULL;
    ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
    if(!GetOpenFileName( &ofn )){ //Check if there is no error while getting the file
        return false;
    }
    FileName = ofn.lpstrFile;
    MessageBox ( NULL , FileName , "File Name" , MB_OK); //check if the filename is correct
	
    if(CArea::AreaControl.OnLoad(FileName) == false) { //Give the file name to try to open it then load the image
        return false;
    }
    return true;
}

bool CArea::OnLoad(char* File) {
    char TilesetFile[260];
    char MapFile[255];
    char DecorFile[255];
    FILE* FileHandle = fopen(File, "r"); //open the file
    if(FileHandle == NULL) {
        return false;
    }
    fscanf(FileHandle, "%s\n", TilesetFile); //Image file path

    if((Surf_Tileset = CSurface::OnLoad(TilesetFile))==NULL){//Try to load the image to a SDL Surface
        return false; //Fails here
    }
    //Not important stuff concerning my problem
    fscanf(FileHandle, "%dx%d,%d\n", &Map_Rows, &Map_Cols,&Tile_Size);
    CTilePicker::CTilePickerControl.OnLoad(Surf_Tileset,Tile_Size);
    fscanf(FileHandle, "%s ", MapFile);
    fscanf(FileHandle, "%s\n", DecorFile);
    fclose(FileHandle);
    FILE* MapFileHandle = fopen(MapFile, "r");
    FILE* DecorFileHandle = fopen(DecorFile, "r");
    if(MapFileHandle == NULL || DecorFileHandle == NULL) {
        return false;
    }
    for(int X = 0;X < Map_Rows;X++) {
        for(int Y = 0;Y < Map_Cols;Y++) {
            fscanf(MapFileHandle, "%d:%d ", &Map_Tiles_ID[X][Y], &Map_Tiles_Type[X][Y]);
            fscanf(DecorFileHandle, "%d:%d ", &Decor_Tiles_ID[X][Y], &Decor_Tiles_Type[X][Y]);
        }
        fscanf(MapFileHandle, "\n");
        fscanf(DecorFileHandle, "\n");
    }
    fclose(MapFileHandle);
    fclose(DecorFileHandle);
    return true;
}

SDL_Surface* CSurface::OnLoad(char* File) {
    SDL_Surface* Surf_Temp = NULL;
    SDL_Surface* Surf_Return = NULL;
    
    if((Surf_Temp = IMG_Load(File)) == NULL) { //Fails here
        return NULL;
    }
    Surf_Return = SDL_DisplayFormatAlpha(Surf_Temp);
    SDL_FreeSurface(Surf_Temp);

    return Surf_Return;
}

If you need some more details, just ask.

Thank you again!

[Peter87]

After you have called fscanf, are you sure that TilesetFile contains the path correctly? Maybe you should print TilesetFile to see if it's correct. You could also print SDL_GetError() after IMG_Load has failed to see what error message SDL is giving.

[freakypanda]

I already did several tests to know what was containing TilesetFile and the path is correct, it's the one that I give in the file. And when I don't use the GetOpenFileName function to get the file name it works correctly...

SDL_GetError() tells me that it couldn't open the file.

So I took a second to think about that and as TilesetFile path was relative to my .exe file I tried to give the absolute path.
It was still not working because there were some spaces in the path so fscanf returned me only the first part of the line.
I could use fgets but I wanted to try to give the relative path of the TilesetFile but, this time, relative to the location of the file that I open to get the path. And guess what? It's working now!
So apparently, as I am opening a file with the absolute path that I got with GetOpenFileName I have to give to IMG_Load the path relative to the file location, not relative to the .exe file.

I hope you understood what I said ^^

Thank you Peter for your help!

[Peter87]

Ah so GetOpenFileName changes the working directory of the program.

[freakypanda]

So, I checked and by default it does change the working directory. But you can add the flag OFN_NOCHANGEDIR to avoid that.
Good to know :)

But I am going to change the fscanf function to fgets and always write absolute path with the flag OFN_NOCHANGEDIR, maybe it will be easier to manage everything.