Spiral animation in Terminal, a bit dirty

spiral.cpp

#include <iostream>
#include <vector>
#include <string>
#include <unistd.h>

using namespace std;

const string CSI{"\x1b["};
const string CYAN{CSI + "36m"};
const string RED{CSI + "31m"};
const string GREEN{CSI + "32m"};
const string YELLOW{CSI + "33m"};
const string RESET{CSI + "30m"};

ostream &curpos(int row, int col) {
    return cout << CSI << row << ';' << col << 'H';
}

typedef vector<vector<char>> field;

const char empty = ' ';
char filled = '@';

enum Direction {
    RIGHT,
    DOWN,
    LEFT,
    UP,
    NONE
};

void init(field& f) {
    for(unsigned i = 0; i < 25; ++i) {
        f.emplace_back();
        for(unsigned j = 0; j < 51; ++j)
            f[i].push_back(empty);
    }
}

bool fill(field& f, unsigned x, unsigned y, Direction c) {
    if(y < f.size() && x < f[y].size()) {
        if(f[y][x] == empty) {
            f[y][x] = filled;

            curpos(y+1, x+1);
            string color = c == RIGHT ? RED :
                            c == DOWN ? GREEN :
                            c == LEFT ? YELLOW :
                            c == UP ? CYAN : RESET;

            string color_bg = color;
            color_bg.replace(color_bg.find("3"), 1, "4");

            std::cout << color_bg << color << filled;
            return true;
        }
    }

    return false;
}

Direction c = RIGHT;
bool iterate(field& f, unsigned& x, unsigned& y, Direction& d, int style) {
    if(style == 0) c = d;
    else if(style == 1) c = (Direction) ((c + 1) % 4);
    else if(style == 2) c = (Direction) (rand() % 4);
    else if(style == 4) c = NONE;

    if(fill(f, x, y, c)) return true;

    if(d == RIGHT) {
        if(fill(f, ++x, y, c)) return true;
        --x;
        d = DOWN;
    }
    else if(d == DOWN) {
        if(fill(f, x, ++y, c)) return true;
        --y;
        d = LEFT;
    }
    else if(d == LEFT) {
        if(fill(f, --x, y, c)) return true;
        ++x;
        d = UP;
    }
    else if(d == UP) {
        if(fill(f, x, --y, c)) return true;
        ++y;
        d = RIGHT;
    }

    return false;
}

bool iterateMulti(field& f, unsigned& x, unsigned& y, Direction& d, int style) {
    bool success = false;
    for(int i = 0; i < 5; ++i)
        if(iterate(f, x, y, d, style))
            success = true;

    if(style != 4) usleep(d == UP || d == DOWN ? 18000 : 1050);
    else usleep(10000);

    return success;
}


void run(int style) {
    field f;
    init(f);

    Direction d = RIGHT;
    unsigned x = 0, y = 0;

    while(iterateMulti(f, x, y, d, style)) {}
}

int main() {
    system("CLS");

    run(2);
    run(4);
    run(1);
    run(4);
    run(0);
    run(4);

    curpos(27, 0);
    return 0;
}