Question

This is my code for snake. system("cls") is not efficient at all, the console flickers...

#include <iostream>
#include <string>
#include <windows.h>
#include <cstdlib>
#include <ctime>
#include <conio.h>
using namespace std;

bool status = false, win = false;

struct Snake {
    int index_i;
    int index_j;
};

class Game {
private:
    enum eDir { UP, RIGHT, DOWN, LEFT };
    eDir direction;
    const int height = 25, width = 50, max_size = (height - 2)*(width - 2);
    int snake_size = 1, food_x, food_y, snake_x, snake_y, score, speed;
    char snake = '@', food = '*', frame = '#';
    Snake *snake_body = new Snake[max_size];
public:
    Game() {
        snake_x = height / 2;
        snake_y = width / 2;
        snake_body[0].index_i = snake_x;
        snake_body[0].index_j = snake_y;
        PutFood();
    }
    ~Game() {
        delete[] snake_body;
    }
    void DrawTable() {
        system("cls");
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                if (!i || i == height - 1 || !j || j == width - 1) {
                    cout << frame;
                }
                else if (i == food_x && j == food_y) {
                    cout << food;
                }
                else if (Check(i, j)) {
                    cout << snake;
                }
                else {
                    cout << " ";
                }
            }
            cout << endl;
        }
        cout << "Your current score is: " << score;
    }
    void Control() {
        if (_kbhit()) {
            switch (_getch()) {
            case 'w':
                direction = UP;
                break;
            case 'a':
                direction = LEFT;
                break;
            case 's':
                direction = DOWN;
                break;
            case 'd':
                direction = RIGHT;
                break;
            }
        }
    }
    void Process() {
        switch (direction) {
        case UP:
            snake_x--;
            Move();
            break;
        case LEFT:
            snake_y--;
            Move();
            break;
        case DOWN:
            snake_x++;
            Move();
            break;
        case RIGHT:
            snake_y++;
            Move();
            break;
        }
    }
    void Move() {
        /*for (int i = 0; i < snake_size; i++) {   tail collision logic (if you try to reverse your move, you die). Optional.
            if (snake_body[i].index_i == snake_x && snake_body[i].index_j == snake_y) {
                status = true;
                return;
            }
        }*/
        snake_body[snake_size].index_i = snake_x;
        snake_body[snake_size].index_j = snake_y;
        if (!snake_x || snake_x == height - 1 || !snake_y || snake_y == width - 1) { // collision logic
            status = true;
        }
        else if (snake_x == food_x && snake_y == food_y) {
            snake_size++;
            score++;
            if (snake_size == max_size) {
                win = true;
                return;
            }
            PutFood();
        }
        else {
            for (int index = 0; index < snake_size; index++) {
                snake_body[index].index_i = snake_body[index + 1].index_i;
                snake_body[index].index_j = snake_body[index + 1].index_j;
            }
            snake_body[snake_size].index_i = 0;
            snake_body[snake_size].index_j = 0;
        }
        Sleep(speed);
    }
    void PutFood() {
        srand(time(NULL));
        food_x = rand() % (height - 2) + 2;
        food_y = rand() % (width - 2) + 2;
    }
    bool Check(int i, int j) {
        for (int k = 0; k < snake_size; k++) {
            if (i == snake_body[k].index_i && j == snake_body[k].index_j) {
                return true;
            }
        }
        return false;
    }
    int getScore() {
        return score;
    }
    void setSpeed(int s) {
        speed = s;
    }
};

int main() {
    Game snake_game;
    char exit;
    string error = "Invalid choice, please choose 1-3";
    int speed, choice;
    cout << "Contol: WASD" << endl << "Set the difficulty level: " << endl << "1. Easy" << endl << "2. Normal" << endl << "3. Hard" << endl;
label:
    cin >> choice;
    try {
        if (choice < 1 || choice > 3) throw error;
    }
    catch (char *error) {
        cout << error << endl;
        goto label;
    }
    switch (choice) {
    case 1:
        speed = 250;
        break;
    case 2:
        speed = 75;
        break;
    case 3:
        speed = 0;
        break;
    }
    snake_game.setSpeed(speed);
    while (!status && !win) {
        snake_game.DrawTable();
        snake_game.Control();
        snake_game.Process();
    }
    if (status && !win) {
        system("cls");
        cout << "YOU LOST! Your score is: " << snake_game.getScore() << endl;
    }
    if (win) {
        system("cls");
        cout << "Congratulations! You won the game!" << endl << "Your score is: " << snake_game.getScore() << endl;
    }
    cin >> exit;
    return 0;
}

Answer 1

system（“ cls”）速度很慢。另外，您无需刷新整个屏幕，因为大多数屏幕不会更改每一帧。我看到您已经包含windows.h，所以我猜您只需要在Windows上运行即可。因此，我建议使用Windows API中的函数。

这是一个例子

   SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), {10, 10});
   std::cout << ' ';

此代码会将光标位置更改为坐标（10，10），并输出一个空格。您可以为每个帧要更改的每个“像素”执行此操作。

Answer 2

在Unix系统上， curses 是实现像您这样的基于文本的程序的经典方法：

使用诅咒，程序员能够编写基于文本的应用程序无需直接编写任何特定的终端类型。诅咒执行系统上的库发送正确的控制字符根据终端类型。它提供一个或多个的抽象映射到终端屏幕的窗口。每个窗口都代表通过字符矩阵。程序员设置所需的外观，然后告诉curses程序包更新屏幕。该库确定了所需的最少更改集更新显示，然后使用终端的具体功能和控制顺序。 [维基百科]

很显然，正在开发一个名为PDCurses的Windows端口。您可以查看它是否满足您的需求。

Answer 3

system("cls")实际上是运行整个Windows程序（cmd.exe）来清除控制台。这当然不是很有效。取而代之的是，我们只需要执行相同的操作，即 cmd.exe 中的 cls 命令。为了获得清晰的屏幕，我们可以使用ScrollConsoleScreenBuffer-将控制台屏幕缓冲区的内容替换为空格

BOOL cls()
{
    HANDLE hConsoleOutput = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    if (GetConsoleScreenBufferInfo(hConsoleOutput, &csbi))
    {
        CHAR_INFO fi = { ' ', csbi.wAttributes };
        csbi.srWindow.Left = 0;
        csbi.srWindow.Top = 0;
        csbi.srWindow.Right = csbi.dwSize.X - 1;
        csbi.srWindow.Bottom = csbi.dwSize.Y - 1;
        return ScrollConsoleScreenBufferW(hConsoleOutput, &csbi.srWindow, 0, csbi.dwSize, &fi);
    }
    return FALSE;
}

Answer 4

system("cls")的效率太低。这是清理屏幕的类似方法：

    //First get the console handle and its info.
    HANDLE hConsoleOut = GetStdHandle(STD_OUTPUT_HANDLE);
    GetConsoleScreenBufferInfo(hConsoleOut, &csbiInfo);

    //Fill with ' ' in the whole console(number = X*Y).
    FillConsoleOutputCharacter(hConsoleOut, ' ', csbiInfo.dwSize.X * csbiInfo.dwSize.Y, home, &dummy);
    csbiInfo.dwCursorPosition.X = 0;
    csbiInfo.dwCursorPosition.Y = 0;

    //Set the Cursor Position to the Beginning.
    SetConsoleCursorPosition(hConsoleOut, csbiInfo.dwCursorPosition);

Answer 5

As you are using conio.h, you can use gotoxy(x, y) to go to the coordinate, which you want to delete and just perform a printf(" ") with a whitespace.

How can I refresh the console in the most efficient way? (snake game c++)

5 个答案: