opengl - 在 GLUT 中使用鼠标滚轮

Question

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

Answer 1

Freeglut 的 glutMouseWheelFunc 回调与版本相关，并且在 X 中不可靠。使用标准鼠标功能并测试按钮 3 和 4。

OpenGlut 关于 glutMouseWheelFunc 状态的注释:

Due to lack of information about the mouse, it is impossible to implement this correctly on X at this time. Use of this function limits the portability of your application. (This feature does work on X, just not reliably.) You are encouraged to use the standard, reliable mouse-button reporting, rather than wheel events.

使用标准的 GLUT 鼠标报告:

#include <GL/glut.h>

<snip...>

void mouse(int button, int state, int x, int y)
{
   // Wheel reports as button 3(scroll up) and button 4(scroll down)
   if ((button == 3) || (button == 4)) // It's a wheel event
   {
       // Each wheel event reports like a button click, GLUT_DOWN then GLUT_UP
       if (state == GLUT_UP) return; // Disregard redundant GLUT_UP events
       printf("Scroll %s At %d %d\n", (button == 3) ? "Up" : "Down", x, y);
   }else{  // normal button event
       printf("Button %s At %d %d\n", (state == GLUT_DOWN) ? "Down" : "Up", x, y);
   }
}

<snip...>

glutMouseFunc(mouse);

正如OP所说，它“非常简单”。他只是错了。