gistfile1.cpp

void Pipeline::platformInit() {
  platform = new PipelinePlatform;
  try {
  Display *dpy = platform->dpy = XOpenDisplay(0);
  if(!dpy)
    throw std::runtime_error("Could not open X11 display!");
  try { // display is open. If we get an error from here down we need to close the display

  // Verify our GLX version is the minimum to be doing our fun stuff
  int glx_major, glx_minor;
  if(!glXQueryVersion(dpy, &glx_major, &glx_minor) || ((glx_major == 1 && glx_minor < 3) || glx_major < 1))
    throw std::runtime_error("GLX 1.3 or greater is required!");

  // Query for an FBConfig that matches our requirements
  int fbcount;
  GLXFBConfig *cfgs = glXChooseFBConfig(dpy, DefaultScreen(dpy), visual_attribs, &fbcount);
  if(!cfgs)
    throw std::runtime_error("No framebuffer that meets our requirements was found!");
  GLXFBConfig fbc = cfgs[0];
  XFree(cfgs);

  // Get the visual and set the window attributes
  XVisualInfo *vi = glXGetVisualFromFBConfig(dpy, fbc);
  if(!vi)
    throw std::runtime_error("Could not get a visual from the fbconfig");
  XSetWindowAttributes swa;
  swa.colormap = platform->cmap = XCreateColormap(dpy, RootWindow(dpy, vi->screen), vi->visual, AllocNone);
  swa.background_pixmap = None;
  swa.border_pixel = 0;
  swa.event_mask = StructureNotifyMask; // TODO: Add more event masks as needed

  // Create the window
  Window win = platform->win = XCreateWindow(dpy, RootWindow(dpy, vi->screen), 0, 0, 800, 600, 0, vi->depth, InputOutput, vi->visual, CWBorderPixel|CWColormap|CWEventMask, &swa);
  if(!win)
    throw std::runtime_error("Could not create X11 window");

  try { // everything from here on needs to close the window if there's an error

  XStoreName(dpy, win, "Deferred Renderer Demo");
  XMapWindow(dpy, win);
  // Query if the needed GLX extensions are present
  const char *glx_ext_string = glXQueryExtensionsString(dpy, DefaultScreen(dpy));
  if(!isExtensionSupported(glx_ext_string, "GLX_ARB_create_context"))
    throw std::runtime_error("GLX_ARB_create_context needs to be supported");
  CreateContextAttribs = (PFNGLXCREATECONTEXTATTRIBSARBPROC)glXGetProcAddress((GLubyte*)"glXCreateContextAttribsARB");
  if(!CreateContextAttribs)
    throw std::runtime_error("Could not get context creation entrypoint from GLX");

  GLXContext ctx = platform->ctx = CreateContextAttribs(dpy, fbc, 0, True, context_attribs);
  if(!ctx)
    throw std::runtime_error("Could not create the OpenGL context");
  try {
  if(!glXIsDirect(dpy, ctx))
    throw std::runtime_error("Can only use a direct context");
  glXMakeContextCurrent(dpy, win, win, ctx);
  } catch (std::exception&) {
    glXDestroyContext(dpy, ctx);
    throw;
  }
  } catch (std::exception&) {
    XDestroyWindow(dpy, win);
    throw;
  }
  } catch (std::exception&) {
    XCloseDisplay(dpy);
    throw;
  }
  } catch(std::exception&) {
    delete platform;
    platform = 0;
    throw;
  }
}

void Pipeline::platformFinish() {
  glXMakeContextCurrent(platform->dpy, 0, 0, 0);
  glXDestroyContext(platform->dpy, platform->ctx);
  XDestroyWindow(platform->dpy, platform->win);
  XFreeColormap(platform->dpy, platform->cmap);
  delete platform;
  platform = 0;
}