几个（7）帧后如何阻止gl挂？

Question

使用OpenGL和X11，我有一个更新X11窗口以创建动画的程序，但动画在几帧后挂起。我该如何解决？

我曾尝试过glClear（GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ACCUM_BUFFER_BIT）和XClearWindow，但无济于事。

完整的代码在这里：https://github.com/alexrockhill/V1Model但这里是与问题相关的部分：

int plot_network(nw)
  struct network nw;
{
  Display               *dpy;
  Window                win;
  Bool                  doubleBuffer = True;
  XVisualInfo           *vi = NULL;
  Colormap              cmap;
  XSetWindowAttributes  swa;
  GLXContext            cx;
  XEvent                event;
  int                   screen_num, t_ind, ori_ind;
  unsigned int          display_width, display_height, size; 
  float                 delta;
  static Bool           displayListInited = False;

  if(!(dpy = XOpenDisplay(NULL)))
    fatalError("could not open display");
  if(!(vi = glXChooseVisual(dpy, DefaultScreen(dpy), dblBuf))) {
    if(!(vi = glXChooseVisual(dpy, DefaultScreen(dpy), sngBuf)))
      fatalError("no RGB visual with depth buffer");
    doubleBuffer = False;
  }
  if(vi->class != TrueColor)
    fatalError("TrueColor visual required for this program");
  if(!(cx = glXCreateContext(dpy, vi, None, True)))
    fatalError("could not create rendering context");
  screen_num = DefaultScreen(dpy);
  display_width = DisplayWidth(dpy, screen_num);
  display_height = DisplayHeight(dpy, screen_num);
  if (display_width < display_height) {
    size = display_width*0.8;
  } else {
    size = display_height*0.8;
  }
  delta = 2.0/nw.dim;
  cmap = XCreateColormap(dpy,RootWindow(dpy,vi->screen),vi->visual,AllocNone);
  swa.colormap = cmap;
  swa.border_pixel = 0;
  swa.event_mask = ExposureMask | ButtonPressMask | StructureNotifyMask;
  win = XCreateWindow(dpy,RootWindow(dpy,vi->screen),0,0,size,size,
    0,vi->depth,InputOutput,vi->visual,
    CWBorderPixel | CWColormap | CWEventMask,
    &swa);
  XSetStandardProperties(dpy,win,"V1 Model","V1 Model",None,None,0,NULL);
  glXMakeCurrent(dpy, win, cx);
  XMapWindow(dpy, win);

  glEnable(GL_DEPTH_TEST);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(0.0,1.0,0.0,0.0,0.0,1.0);

  t_ind = 0;
  while(t_ind < nw.n_steps) {
    XNextEvent(dpy, &event);
    //XClearWindow(dpy, win);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ACCUM_BUFFER_BIT);
    for(int i=0;i<nw.dim;i++){
        for(int j=0;j<nw.dim;j++){
            float v = 0;
            for (int k=0; k < nw.oris; k++) {
                v += nw.cols[i][j].ns[k].v[t_ind];
            }
            v /= (float) nw.oris;
            float x = nw.cols[i][j].ns[0].x*delta-1;
            float y = nw.cols[i][j].ns[0].y*delta-1;
            draw_box(red(v), green(v), blue(v), x, y, delta, delta);
        }
    }
    if(doubleBuffer)
      glXSwapBuffers(dpy, win); 
    else
      glFlush();
    printf("Time: %i\n", t_ind);
    usleep(500000);
    t_ind++;
  }
  XCloseDisplay(dpy);
  return(0);
}

我希望动画能够继续播放n_steps个时间点>> 7，但它只会在几（7）个动画更新后挂起。

Answer 1

问题可能是你使用XNextEvent;例如，如果您生成的事件比渲染速度快，则无法清除事件队列。另一方面，如果事件队列中没有事件，您将在此功能中挂起，直到您执行此操作。

尝试

for(int i = 0; i < XEventsQueued(dpy, QueuedAlready); ++i) {
  XNextEvent(dpy, &event);
  // handle event here
}

代替。免责声明：因为我从未在生活中直接使用过Xlib，所以要带上一粒盐。