使用glutIdleFunc摆脱glutMainLoop？

Question

我正在写一个程序，打开并打开一个图像的GL窗口，并连接到我的Android设备，用户使用该设备作为一种触控板来平移和放大和缩小。所有工作正常，但程序卡在glutMainLoop中，不会继续接收设备中的数据。显然glutIdleFunc是我的问题的解决方案，但我不能看到如何在我的代码中实现这个没有得到内存错误？有人能告诉我如何将函数放入我的代码中，以便运行连接代码以及opengl的东西吗？

#include <stdlib.h> 
#include <stdio.h> 
#include <signal.h> 
#include <string.h> 
#include <strings.h> 
#include <vrpn_Shared.h> 
#include <vrpn_Analog.h> 
#include <vector> 
#include <GL/freeglut.h> 
#include <imageviewer.h> 

using namespace std; 

int done = 0; 
int accepted = 0;   // Signals that the program should exit 
unsigned tracker_stride = 1; // Every nth report will be printed 


//------------------------------------- 
// This section contains the data structure that holds information on 
// the devices that are created. For each named device, a remote of each 
// type analog is created. 

class device_info { 
    public: 
    char   *name; 

    vrpn_Analog_Remote *ana; 

}; 
const unsigned MAX_DEVICES = 2; 


//------------------------------------- 
// This section contains the data structure that is used to determine how 
// often to print a report for each sensor of each tracker. Each element 
// contains a counter that is used by the callback routine to keep track 
// of how many it has skipped. There is an element for each possible sensor. 
// A new array of elements is created for each new tracker object, and a 
// pointer to it is passed as the userdata pointer to the callback handlers. 


class t_user_callback { 
    public: 
    char   t_name[vrpn_MAX_TEXT_LEN]; 
     vector<unsigned> t_counts ; 
}; 

//Callback handlers 

void VRPN_CALLBACK handle_analog (void *userdata, const vrpn_ANALOGCB a) 
{ 
    int i; 
    const char *name = (const char *)userdata; 

    printf("Input from %s:\n \n  %5.0f", name, a.channel[0]); 
    for (i = 1; i < a.num_channel; i++) { 
    printf(" %5.0f \n", a.channel[1]); 
    } 
    printf(" \n"); 
} 




int main (int argc, char * argv []) 
{ 

    int print_for_tracker = 1; // Print tracker reports? 
    int print_for_button = 1; // Print button reports? 
    int print_for_analog = 1; // Print analog reports? 
    int print_for_dial = 1; // Print dial reports? 
    int print_for_text = 1; // Print warning/error messages? 


    device_info device_list[MAX_DEVICES]; 
    unsigned num_devices = 0; 


    int i; 

    // Parse arguments, creating objects 

    for (i = 1; i < argc; i++) { 
    if (!strcmp(argv[i], "-notracker")) { 
     print_for_tracker = 0; 
    } else if (!strcmp(argv[i], "-nobutton")) { 
     print_for_button = 0; 
    } else if (!strcmp(argv[i], "-noanalog")) { 
     print_for_analog = 0; 
    } else if (!strcmp(argv[i], "-nodial")) { 
     print_for_dial = 0; 
    } else if (!strcmp(argv[i], "-notext")) { 
     print_for_text = 0; 

    } else if (!strcmp(argv[i], "-trackerstride")) { 
     if (tracker_stride <= 0) { 
     fprintf(stderr, "-trackerstride argument must be 1 or greater\n"); 
     return -1; 
     } 
    } else { // Create a device and connect to it. 
    device_info *dev; 



    // Name the device and open it as everything 
    dev = &device_list[num_devices]; 
    dev->name = argv[i]; 

    dev->ana = new vrpn_Analog_Remote(dev->name); 


    if (print_for_analog) { 
     printf(" Analog"); 
     dev->ana->register_change_handler(dev->name, handle_analog); 
    } 
    printf(".\n"); 
    num_devices++; 
    } 

    } 

// main interactive loop 

    printf("Press ^C to exit.\n"); 
    while (! done) { 
     unsigned i; 

     // Let all the devices do their things 
     for (i = 0; i < num_devices; i++) { 

     device_list[i].ana->mainloop(); 

     glutInit(&argc, argv); 
    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); 
    glutInitWindowSize(400,300); 
    glutInitWindowPosition(200,100); 
    glutCreateWindow("ImageViewer"); 


    init(); 
    glutDisplayFunc(display); 
    glutMotionFunc(drag); 
    glutMouseFunc(mouse); 
// glutIdleFunc(IdleFunc); 
    glutMainLoop(); 

     } 
    } 
return 0; 
} 

Answer 1

如果它可以管理所有的输入设备，并且所有设备都由它管理的输入事件驱动，那么过剩就是好事。一旦你有非托管输入设备或非基于事件的处理，你可能想要使用除了过剩以外的东西。你的另一种选择是在单独的进程（或线程）中分叉和运行异步的东西。