如何在Windows上的C ++中访问低级硬件I/O功能? [英] How can I access a low-level hardware I/O functions in C++ on Windows?

问题描述

我正在用C ++编写游戏，我需要检测用户何时按下键.通常，我会使用std::cin，但是我有一个使用graphics.h的图形窗口，该窗口最初是古老的Borland Turbo C ++编译器提供的标头，但可以在网上找到等效的标头.因此，我将使用函数inportb();以及类似这样的函数定义:

I am writing a game in C++, and I need to detect when the user presses a key. Usually, I would use std::cin, but I have a graphical window, using graphics.h, a header that was originally provided with the ancient Borland Turbo C++ compiler, but an equivalent is available online. So, I would use the function inportb();, with a function definition like this:

inline unsigned char inportb(unsigned int port) {
    unsigned char ret;
    asm volatile ("inb %%dx,%%al":"=a"(ret):"d"(port));
    return ret;
}

来源: inportb .

但是在Windows中，像这样的直接低级硬件I/O受保护，并且，如果尝试这样做，该程序将被杀死.因此，我需要通过高级函数或API来访问该函数.

But in Windows, direct low-level hardware I/O like that is protected, and, if it is attempted, the program will be killed. So I need to access that function via a high-level function or API.

我的问题:我该怎么做?

My question: How can I do this?

推荐答案

如果尝试在游戏循环中间检测特定键的状态，则

If you are attempting to detect the state of a specific key in the middle of your game loop, the GetAsyncKeyState will determine the specific state at that moment.

if (GetAsyncKeyState(VK_LEFT) & 0x8000) != 0u)
{
    // ...
}

此功能需要虚拟键代码(在这种情况下为左箭头键)，获取状态，然后按位进行与"操作，确定键是否按下，然后关闭.

This function takes a virtual key code (in this case the left arrow key), get the state and after a bitwise AND operation to determine if the key is down, then off you go.

这些虚拟密钥代码可以在WinUser.h中找到. GetAsyncKeyState 与 GetKeyState 在该 GetKeyState 不反映中断与硬件相关联的级别状态(这就是为什么我使用 GetAsyncKeyState ).如果您需要给定实例上的所有关键状态(这种情况很少见)，请考虑

These virtual key codes can be found in WinUser.h. GetAsyncKeyState differs from GetKeyState in that GetKeyState does not reflect the interrupt-level state associated with the hardware (which is why I used GetAsyncKeyState above). If you need all of the key states at a given instance (which is rare), consider GetKeybardState.

但是，如果您正在等待按键事件( WM_KEYDOWN ， WM_CHAR ，

However, if you are waiting for a key event (WM_KEYDOWN, WM_CHAR, WM_KEYUP) to occur, you must provide a case in the window procedure to handle that event.

LRESULT WindowProc(UINT const message, WPARAM const wparam, LPARAM const lparam)
{
    switch(message)
    {

    // [ cases like WM_CREATE / WM_PAINT / WM_CLOSE / WM_DESTROY ]

    case WM_KEYDOWN:
        // handle event here
        break;

    case WM_CHAR:
        // handle event here
        break;

    case WM_KEYUP:
        // handle event here
        break;
    }
}

希望这会有所帮助.

这篇关于如何在Windows上的C ++中访问低级硬件I/O功能?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！