Attachment 50707 Details for Bug 40423 – Stand-alone version of Mozilla's glxtext, v2

Stand-alone version of Mozilla's glxtext, v2

glxtest.cpp (text/x-c++src), 9.58 KB, created by Benoit Jacob on 2011-08-30 14:00:11 UTC

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Creator: Benoit Jacob

Created: 2011-08-30 14:00:11 UTC

Size: 9.58 KB

patch

obsolete

>/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
> * vim: sw=2 ts=8 et :
> */
>/* ***** BEGIN LICENSE BLOCK *****
> * Version: MPL 1.1/GPL 2.0/LGPL 2.1
> *
> * The contents of this file are subject to the Mozilla Public License Version
> * 1.1 (the "License"); you may not use this file except in compliance with
> * the License. You may obtain a copy of the License at:
> * http://www.mozilla.org/MPL/
> *
> * Software distributed under the License is distributed on an "AS IS" basis,
> * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
> * for the specific language governing rights and limitations under the
> * License.
> *
> * The Original Code is Mozilla Code.
> *
> * The Initial Developer of the Original Code is
> *   The Mozilla Foundation
> * Portions created by the Initial Developer are Copyright (C) 2010
> * the Initial Developer. All Rights Reserved.
> *
> * Contributor(s):
> *
> * Alternatively, the contents of this file may be used under the terms of
> * either the GNU General Public License Version 2 or later (the "GPL"), or
> * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
> * in which case the provisions of the GPL or the LGPL are applicable instead
> * of those above. If you wish to allow use of your version of this file only
> * under the terms of either the GPL or the LGPL, and not to allow others to
> * use your version of this file under the terms of the MPL, indicate your
> * decision by deleting the provisions above and replace them with the notice
> * and other provisions required by the GPL or the LGPL. If you do not delete
> * the provisions above, a recipient may use your version of this file under
> * the terms of any one of the MPL, the GPL or the LGPL.
> *
> * ***** END LICENSE BLOCK ***** */
>
>
>//////////////////////////////////////////////////////////////////////////////
>//
>// Explanation: See bug 639842. Safely getting GL driver info on X11 is hard, because the only way to do
>// that is to create a GL context and call glGetString(), but with bad drivers,
>// just creating a GL context may crash.
>//
>// This file implements the idea to do that in a separate process.
>//
>// The only non-static function here is fire_glxtest_process(). It creates a pipe, publishes its 'read' end as the
>// mozilla::widget::glxtest_pipe global variable, forks, and runs that GLX probe in the child process,
>// which runs the glxtest() static function. This creates a X connection, a GLX context, calls glGetString, and writes that
>// to the 'write' end of the pipe.
>
>#include <cstdio>
>#include <cstdlib>
>#include <unistd.h>
>#include <GL/gl.h>
>#include <GL/glx.h>
>#include <dlfcn.h>
>#include <string.h>
>//#include "nscore.h"
>
>// the write end of the pipe, which we're going to write to
>// XXX replaced by standard output
>static int write_end_of_the_pipe = 0;
>
>// C++ standard collides with C standard in that it doesn't allow casting void* to function pointer types.
>// So the work-around is to convert first to size_t.
>// http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
>template<typename func_ptr_type>
>static func_ptr_type cast(void *ptr)
>{
>  return reinterpret_cast<func_ptr_type>(
>           reinterpret_cast<size_t>(ptr)
>         );
>}
>
>static void fatal_error(const char *str)
>{
>  write(write_end_of_the_pipe, str, strlen(str));
>  write(write_end_of_the_pipe, "\n", 1);
>  exit(EXIT_FAILURE);
>}
>
>static int
>x_error_handler(Display *, XErrorEvent *ev)
>{
>  enum { bufsize = 1024 };
>  char buf[bufsize];
>  int length = snprintf(buf, bufsize,
>                        "X error occurred in GLX probe, error_code=%d, request_code=%d, minor_code=%d\n",
>                        ev->error_code,
>                        ev->request_code,
>                        ev->minor_code);
>  write(write_end_of_the_pipe, buf, length);
>  exit(EXIT_FAILURE);
>  return 0;
>}
>
>static void glxtest()
>{
>  ///// Open libGL and load needed symbols /////
>  void *libgl = dlopen("libGL.so.1", RTLD_LAZY);
>  if (!libgl)
>    fatal_error("Unable to load libGL.so.1");
>
>  typedef GLXFBConfig* (* PFNGLXQUERYEXTENSION) (Display *, int *, int *);
>  PFNGLXQUERYEXTENSION glXQueryExtension = cast<PFNGLXQUERYEXTENSION>(dlsym(libgl, "glXQueryExtension"));
>
>  typedef GLXFBConfig* (* PFNGLXQUERYVERSION) (Display *, int *, int *);
>  PFNGLXQUERYVERSION glXQueryVersion = cast<PFNGLXQUERYVERSION>(dlsym(libgl, "glXQueryVersion"));
>
>  typedef GLXFBConfig* (* PFNGLXCHOOSEFBCONFIG) (Display *, int, const int *, int *);
>  PFNGLXCHOOSEFBCONFIG glXChooseFBConfig = cast<PFNGLXCHOOSEFBCONFIG>(dlsym(libgl, "glXChooseFBConfig"));
>
>  typedef XVisualInfo* (* PFNGLXGETVISUALFROMFBCONFIG) (Display *, GLXFBConfig);
>  PFNGLXGETVISUALFROMFBCONFIG glXGetVisualFromFBConfig = cast<PFNGLXGETVISUALFROMFBCONFIG>(dlsym(libgl, "glXGetVisualFromFBConfig"));
>
>  typedef GLXPixmap (* PFNGLXCREATEPIXMAP) (Display *, GLXFBConfig, Pixmap, const int *);
>  PFNGLXCREATEPIXMAP glXCreatePixmap = cast<PFNGLXCREATEPIXMAP>(dlsym(libgl, "glXCreatePixmap"));
>
>  typedef GLXContext (* PFNGLXCREATENEWCONTEXT) (Display *, GLXFBConfig, int, GLXContext, Bool);
>  PFNGLXCREATENEWCONTEXT glXCreateNewContext = cast<PFNGLXCREATENEWCONTEXT>(dlsym(libgl, "glXCreateNewContext"));
>
>  typedef Bool (* PFNGLXMAKECURRENT) (Display*, GLXDrawable, GLXContext);
>  PFNGLXMAKECURRENT glXMakeCurrent = cast<PFNGLXMAKECURRENT>(dlsym(libgl, "glXMakeCurrent"));
>
>  typedef void (* PFNGLXDESTROYPIXMAP) (Display *, GLXPixmap);
>  PFNGLXDESTROYPIXMAP glXDestroyPixmap = cast<PFNGLXDESTROYPIXMAP>(dlsym(libgl, "glXDestroyPixmap"));
>
>  typedef void (* PFNGLXDESTROYCONTEXT) (Display*, GLXContext);
>  PFNGLXDESTROYCONTEXT glXDestroyContext = cast<PFNGLXDESTROYCONTEXT>(dlsym(libgl, "glXDestroyContext"));
>
>  typedef GLubyte* (* PFNGLGETSTRING) (GLenum);
>  PFNGLGETSTRING glGetString = cast<PFNGLGETSTRING>(dlsym(libgl, "glGetString"));
>
>  typedef void* (* PFNGLXGETPROCADDRESS) (const char *);
>  PFNGLXGETPROCADDRESS glXGetProcAddress = cast<PFNGLXGETPROCADDRESS>(dlsym(libgl, "glXGetProcAddress"));
>
>  if (!glXQueryExtension ||
>      !glXQueryVersion ||
>      !glXChooseFBConfig ||
>      !glXGetVisualFromFBConfig ||
>      !glXCreatePixmap ||
>      !glXCreateNewContext ||
>      !glXMakeCurrent ||
>      !glXDestroyPixmap ||
>      !glXDestroyContext ||
>      !glGetString ||
>      !glXGetProcAddress)
>  {
>    fatal_error("Unable to find required symbols in libGL.so.1");
>  }
>  ///// Open a connection to the X server /////
>  Display *dpy = XOpenDisplay(NULL);
>  if (!dpy)
>    fatal_error("Unable to open a connection to the X server");
>  
>  ///// Check that the GLX extension is present /////
>  if (!glXQueryExtension(dpy, NULL, NULL))
>    fatal_error("GLX extension missing");
>  
>  ///// Check that the GLX version is >= 1.3, needed for glXCreatePixmap, bug 659932 /////
>  int majorVersion, minorVersion;
>  if (!glXQueryVersion(dpy, &majorVersion, &minorVersion))
>    fatal_error("Unable to query GLX version");
>
>  if (majorVersion < 1 || (majorVersion == 1 && minorVersion < 3))
>    fatal_error("GLX version older than the required 1.3");
>
>  XSetErrorHandler(x_error_handler);
>
>  ///// Get a FBConfig and a visual /////
>  int attribs[] = {
>    GLX_DRAWABLE_TYPE, GLX_PIXMAP_BIT,
>    GLX_X_RENDERABLE, True,
>    0
>  };
>  int numReturned;
>  GLXFBConfig *fbConfigs = glXChooseFBConfig(dpy, DefaultScreen(dpy), attribs, &numReturned );
>  if (!fbConfigs)
>    fatal_error("No FBConfigs found");
>  XVisualInfo *vInfo = glXGetVisualFromFBConfig(dpy, fbConfigs[0]);
>  if (!vInfo)
>    fatal_error("No visual found for first FBConfig");
>
>  ///// Get a Pixmap and a GLXPixmap /////
>  Pixmap pixmap = XCreatePixmap(dpy, RootWindow(dpy, vInfo->screen), 4, 4, 32);
>  GLXPixmap glxpixmap = glXCreatePixmap(dpy, fbConfigs[0], pixmap, NULL);
>
>  ///// Get a GL context and make it current //////
>  GLXContext context = glXCreateNewContext(dpy, fbConfigs[0], GLX_RGBA_TYPE, NULL, True);
>  glXMakeCurrent(dpy, glxpixmap, context);
>
>  ///// Look for this symbol to determine texture_from_pixmap support /////
>  void* glXBindTexImageEXT = glXGetProcAddress("glXBindTexImageEXT"); 
>
>  ///// Get GL vendor/renderer/versions strings /////
>  enum { bufsize = 1024 };
>  char buf[bufsize];
>  const GLubyte *vendorString = glGetString(GL_VENDOR);
>  const GLubyte *rendererString = glGetString(GL_RENDERER);
>  const GLubyte *versionString = glGetString(GL_VERSION);
>  
>  if (!vendorString || !rendererString || !versionString)
>    fatal_error("glGetString returned null");
>
>  int length = snprintf(buf, bufsize,
>                        "VENDOR\n%s\nRENDERER\n%s\nVERSION\n%s\nTFP\n%s\n",
>                        vendorString,
>                        rendererString,
>                        versionString,
>                        glXBindTexImageEXT ? "TRUE" : "FALSE");
>  if (length >= bufsize)
>    fatal_error("GL strings length too large for buffer size");
>
>  ///// Check that no X error happened /////
>  // In case of X errors, our X error handler will exit() now.
>  // We really want to make sure that the system is able to create a GL context without generating X errors,
>  // as these would crash the application.
>  XSync(dpy, False);
>  
>  ///// Finally write data to the pipe /////
>  write(write_end_of_the_pipe, buf, length);
>
>  ///// Clean up. Indeed, the parent process might fail to kill us (e.g. if it doesn't need to check GL info)
>  ///// so we might be staying alive for longer than expected, so it's important to consume as little memory as
>  ///// possible. Also we want to check that we're able to do that too without generating X errors.
>  glXMakeCurrent(dpy, None, NULL); // must release the GL context before destroying it
>  glXDestroyContext(dpy, context);
>  glXDestroyPixmap(dpy, glxpixmap);
>  XFreePixmap(dpy, pixmap);
>  XCloseDisplay(dpy);
>  dlclose(libgl);
>}
>
>int main(int argc, char **argv)
>{
>  glxtest();
>  return 0;
>}

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Attachments on bug 40423: 50665 | 50707 | 50724

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