void MazeGen::generate_maze()

in procgen/src/mazegen.cpp [112:187]

• 61 lines of code
• 16 McCabe index (conditional complexity)

void MazeGen::generate_maze() {
    for (int i = 0; i < array_dim; i++) {
        for (int j = 0; j < array_dim; j++) {
            grid.set(i, j, WALL_OBJ);
        }
    }

    grid.set(MAZE_OFFSET, MAZE_OFFSET, 0);

    std::vector<Wall> walls;

    num_free_cells = 0;
    free_cell_set.clear();

    std::set<int> *s0 = &cell_sets[0];
    s0->clear();
    s0->insert(0);
    cell_sets_idxs[0] = 0;

    for (int i = 1; i < maze_dim * maze_dim; i++) {
        std::set<int> *s1 = &cell_sets[i];
        s1->clear();
        s1->insert(i);
        cell_sets_idxs[i] = i;
    }

    for (int i = 1; i < maze_dim; i += 2) {
        for (int j = 0; j < maze_dim; j += 2) {
            if (i > 0 && i < maze_dim - 1) {
                walls.push_back(Wall({i - 1, j, i + 1, j}));
            }
        }
    }

    for (int i = 0; i < maze_dim; i += 2) {
        for (int j = 1; j < maze_dim; j += 2) {
            if (j > 0 && j < maze_dim - 1) {
                walls.push_back(Wall({i, j - 1, i, j + 1}));
            }
        }
    }

    while (walls.size() > 0) {
        int n = rand_gen->randn((int)(walls.size()));
        Wall wall = walls[n];

        int s0_idx = lookup(wall.x1, wall.y1);
        s0 = &cell_sets[s0_idx];
        int s1_idx = lookup(wall.x2, wall.y2);
        std::set<int> *s1 = &cell_sets[s1_idx];

        int x0 = (wall.x1 + wall.x2) / 2;
        int y0 = (wall.y1 + wall.y2) / 2;
        int center = maze_dim * y0 + x0;

        bool can_remove =
            (grid.get(x0 + MAZE_OFFSET, y0 + MAZE_OFFSET) == WALL_OBJ) &&
            (s0_idx != s1_idx);

        if (can_remove) {
            set_free_cell(wall.x1, wall.y1);
            set_free_cell(x0, y0);
            set_free_cell(wall.x2, wall.y2);

            s1->insert(s0->begin(), s0->end());
            s1->insert(center);

            std::set<int>::iterator it;
            for (it = s1->begin(); it != s1->end(); ++it) {
                cell_sets_idxs[*it] = s1_idx;
            }
        }

        walls.erase(walls.begin() + n);
    }
}