GLUT键按下并在CTRL键上按下 [英] GLUT key down and key up on CTRL key

问题描述

我发现了很多有关使用GLUT来检测是否使用GLUT_ACTIVE_CTRL宏按下 Ctrl 键的信息.显然，此宏仅在键盘或鼠标回调函数中有效.我需要知道是否在主循环中的某个点按下了 Ctrl 键，但是GLUT_ACTIVE_CTRL在这种情况下似乎不起作用.

I've found a lot of information about using GLUT to detect whether the Ctrl key is pressed using the GLUT_ACTIVE_CTRL macro. This macro only works, apparently, within a keyboard or mouse callback function. I need to know whether or not the Ctrl key is pressed at a point in my main loop, but GLUT_ACTIVE_CTRL doesn't seem to work in this context.

那么，有没有一种方法可以以平台无关的GLUT式方式检测 Ctrl 键上的键上移和键下事件(无需键入任何其他键)?

So, is there a way to detect key up and key down events on the Ctrl key (without any other keys being typed) in a platform independent GLUT-ish way?

按下 Ctrl 键时，不会触发键盘回调(至少对于默认设置而言).这是一个基本问题，我只能测试按下另一个键时是否按下了 Ctrl 键，从而触发了键盘回调.

The keyboard callback is not fired (at least for a default setup) when the Ctrl key is pressed. This is the basic problem, that I can only test whether the Ctrl key is or isn't pressed when another key is pressed and thus fires the keyboard callback.

我的设置类似于:

// ... in main function:
glutKeyboardFunc(keyboard);

//later in the code: 

void keyboard(unsigned char key, int _x, int _y)
{
    printf("keydown \n");

    if (glutGetModifiers() == GLUT_ACTIVE_CTRL) {
            printf("control key is pressed.\n");
    }
    //etc.

当我按下任何普通字符时，"keydown"将被打印到标准输出.当我按 Ctrl 键时，什么也没发生.如果我按 Ctrl + C ，则按下了键盘控制键."已打印.

When I press any normal character "keydown " is printed to stdout. When I press the Ctrl key, nothing happens. If I press Ctrl+C, "keydown control key is pressed." is printed.

但是，在主循环中我添加了:

However, in my main loop I added:

if (glutGetModifiers() == GLUT_ACTIVE_CTRL) {
    printf("Control key down.\n");
} else {
    printf("Control key up.\n");
}

，并且始终打印"Control key up".不管我是否按下 Ctrl 键.

and it always prints "Control key up." regardless of whether I am pressing the Ctrl key or not.

推荐答案

不使用GLUT GLFW .

Not using GLUT as specced. You may wish to check out GLFW.

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