在GLUT中使用鼠标滚轮 [英] Using the mouse scrollwheel in GLUT

问题描述

我想在OpenGL GLUT程序中使用鼠标滚轮来放大和缩小场景吗?我该怎么办?

I want to use the mouse scrollwheel in my OpenGL GLUT program to zoom in and out of a scene? How do I do that?

推荐答案

请注意，古老的内特·罗宾(Nate Robin) GLUT 库不支持滚轮.但是，像 FreeGLUT 这样的GLUT更高版本可以实现.

Note that venerable Nate Robin's GLUT library doesn't support the scrollwheel. But, later implementations of GLUT like FreeGLUT do.

在FreeGLUT中使用滚轮非常简单.方法如下:

Using the scroll wheel in FreeGLUT is dead simple. Here is how:

声明一个回调函数，每当滚动滚轮滚动时应调用该回调函数.这是原型:

Declare a callback function that shall be called whenever the scroll wheel is scrolled. This is the prototype:

void mouseWheel(int, int, int, int);

使用(免费)GLUT函数 glutMouseWheelFunc()注册回调.

Register the callback with the (Free)GLUT function glutMouseWheelFunc().

glutMouseWheelFunc(mouseWheel);

定义回调函数.第二个参数给出滚动的方向. +1表示正向，-1表示反向.

Define the callback function. The second parameter gives the direction of the scroll. Values of +1 is forward, -1 is backward.

void mouseWheel(int button, int dir, int x, int y)
{
    if (dir > 0)
    {
        // Zoom in
    }
    else
    {
        // Zoom out
    }

    return;
}

就是这样！

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