ASCII_Snake.cpp

Snake.cpp

#include <iostream>
#include <conio.h>
#include <chrono>
#include <thread>
using namespace std;
//game state
bool gameOver = false;
//MAP BLOCKS
const int width = 20;
const int height = 20;

//head position
int x, y;

//body
int tailX[100], tailY[100];
int nTail = 0;

//fruit position
int fruitX, fruitY;

//scores
int score;

//direction of the snake
enum eDirection { STOP = 0, LEFT, RIGHT, UP, DOWN };
eDirection dir;

//draw speed
long long lastDrawTime = 0;
const long long millisecondsPerFrame = 60;
chrono::duration<long long, ratio<1, 1000>> SleepTime(100);
long long GetMillisecondsTime(){ return chrono::duration_cast<std::chrono::milliseconds>(chrono::system_clock::now().time_since_epoch()).count();}

void PlaceFruit()
{
    fruitX = rand() % width;
    fruitY = rand() % height;
}

void Setup()
{
    gameOver = false;
    dir = STOP;
    //position in the head -> middle of the screen
    x = width/2;
    y = height / 2;
    PlaceFruit();
    score = 0;
    nTail = 0;
    lastDrawTime = GetMillisecondsTime() + millisecondsPerFrame;
}

void DrawLine()
{
    for (int i = 0; i < width + 2; i++)
    {
        cout << "#";
    }
}

void Draw()
{
    const auto time = GetMillisecondsTime();
    if (time > lastDrawTime) lastDrawTime = time + millisecondsPerFrame;
    else return;
    system("cls"); //windows //system("clear"); //Linux
    DrawLine();
    cout << endl;
    for(int i=0; i<height; i++)
    {
        for(int j=0;j<width;j++)
        {
            if (j == 0)
            {
                cout << "#";
            }
            if (i == y && j == x) 
            {
                cout << "O";
            }
            else if (i == fruitY && j == fruitX)
                cout << "X";
            else
            {
                bool printed = false;
                for(int k=0;k<nTail;k++)
                {
                    
                    if(tailX[k]==j && tailY[k]==i)
                    {
                        cout << "o";
                        printed = true;
                    }
                }
                if (!printed)
                    cout << " ";
            }
            //wall
            if (j == width - 1)
            {
                cout << "#";
            }
        }
        cout << endl;
    }
    //bottom
    DrawLine();
    cout << endl << "Score: " << score << endl;
}

void Input()
{
    if(_kbhit()) //async functions to get keyboard pressed keys
    {
        switch(_getch())
        {
        case 'a': if (dir == RIGHT && nTail > 0) gameOver = true; else dir = LEFT; break;
        case 'd':if (dir == LEFT && nTail > 0) gameOver = true; else dir = RIGHT; break;
        case 'w': if (dir == DOWN && nTail > 0) gameOver = true; else dir = UP; break;
        case 's': if (dir == UP && nTail > 0) gameOver = true; else dir = DOWN; break;
        case 'x': gameOver = true;break;
        default: ;
        }
    }
}

void Logic()
{
    int prevX = tailX[0];     //cache tail
    int prevY = tailY[0];
    tailX[0] = x;
    tailY[0] = y;
    for(int i=1;i<nTail; i++) //move the tail
    {   
        int prev2X = tailX[i];
        int prev2Y = tailY[i];
        tailX[i] = prevX;
        tailY[i] = prevY;
        prevX = prev2X;
        prevY = prev2Y;
    }
    switch (dir)
    {
    case STOP: break;
    case LEFT: x--; break;
    case RIGHT: x++;  break;
    case UP: y--;  break;
    case DOWN: y++;  break;
    default: ;
    }
    if (x > width || x<0 || y>height || y < 0)
    {
        gameOver = true;
    }
    else 
    {
        for (int i = 0; i < nTail && !gameOver; i++)
        {
            if(tailX[i]==x && tailY[i]==y)
            {
                gameOver = true;;
            }
        }
        if (!gameOver && x == fruitX && y == fruitY)
        {
            score += 10;
            PlaceFruit();
            nTail++;
        }
    }
}

int main()
{
    Setup();
    while(!gameOver)
    {
        Draw();
        Input();
        Logic();
        this_thread::sleep_for(std::chrono::milliseconds(SleepTime));
    }
    return 0;
}