Method buildTileDistance

source/gamemap/TileContainer.cpp:645–719

}

void TileContainer::buildTileDistance(int distance)
{
    if(mTileDistanceComputed >= distance)
        return;

    // We want to be able to fill a vector of tiles sorted beginning with the closest tile. If we look a grid (each letter
    // represents a tile at the same distance from the center: a):
    // jihghij
    // ifedefi
    // hecbceh
    // gdbabdg
    // hecbceh
    // ifedefi
    // jihghij
    // We can see that there are 3 kind of tiles:
    // - Vertical/Horizontal tiles (abdg): at each distance, there are 4 of them
    // - Diagonal tiles (acfj): at each distance, there are 4 of them
    // - Other tiles (ehi...): at each distance, there are 8 of them
    // Moreover, we can see a symmetry. We can compute all tiles by computing only 1/8 tiles:
    //    j
    //   fi
    //  ceh
    // abdg

    // If we compute only the minimum tiles needed, we have no vertical tiles (since each of them can be deduced from the horizontal)
    // To compute tiles easily, we will compute the 1/8 tiles until distance. Then, we will sort the tiles to begin with
    // closest distance until farthest
    mTileDistance.clear();
    for(int y = 0; y <= distance; ++y)
    {
        for(int x = y; x <= distance; ++x)
        {
            TileDistance::TileDistanceType type;
            if(y == 0)
            {
                type = TileDistance::TileDistanceType::Horizontal;
            }
            else if(x == y)
            {
                type = TileDistance::TileDistanceType::Diagonal;
            }
            else
            {
                type = TileDistance::TileDistanceType::Other;
            }
            int distSquared = x * x + y * y;
            mTileDistance.push_back(TileDistance(x, y, type, distSquared));
        }
    }

    std::sort(mTileDistance.begin(), mTileDistance.end(), sortByDistSquared);

    // We have filled the tile distance vector. Now, we fill how each tile hides the
    // other ones when they mask vision to help calculate visible tiles
    for(TileDistance& tileDistance : mTileDistance)
    {
        // We don't process the first tile
        if(tileDistance.getDiffX() == 0 && tileDistance.getDiffY() == 0)