vtk-m/vtkm/interop/testing/UnitTestFancyTransferGLUT.cxx
2019-04-17 10:57:13 -06:00

106 lines
3.5 KiB
C++

//============================================================================
// Copyright (c) Kitware, Inc.
// All rights reserved.
// See LICENSE.txt for details.
//
// This software is distributed WITHOUT ANY WARRANTY; without even
// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE. See the above copyright notice for more information.
//============================================================================
// OpenGL Graphics includes
//glew needs to go before glut
#include <GL/glew.h>
#include <vtkm/interop/internal/OpenGLHeaders.h>
#if defined(__APPLE__)
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#include <vtkm/interop/testing/TestingTransferFancyHandles.h>
#include <vtkm/internal/Configure.h>
#if (defined(VTKM_GCC) || defined(VTKM_CLANG))
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif
#if defined(VTKM_GCC) && defined(VTKM_POSIX) && !defined(__APPLE__)
//
// 1. Some Linux distributions default linker implicitly enables the as-needed
// linking flag. This means that your shared library or executable will only
// link to libraries from which they use symbols. So if you explicitly link to
// pthread but don't use any symbols you won't have a 'DT_NEEDED' entry for
// pthread.
//
// 2. NVidia libGL (driver version 352 ) uses pthread but doesn't have
// a DT_NEEDED entry for the library. When you run ldd or readelf on the library
// you won't detect any reference to the pthread library. Aside this is odd
// since the mesa version does explicitly link to pthread. But if you run the
// following command:
// "strings /usr/lib/nvidia-352/libGL.so.1 | grep pthread | less"
// You will see the following:
// { pthread_create
// pthread_self
// pthread_equal
// pthread_key_crea
// ...
// libpthread.so.0
// libpthread.so
// pthread_create
// }
//
// This is very strong evidence that this library is using pthread.
//
//
// 3. So what does this all mean?
//
// It means that on system that use the linking flag 'as-needed', are using
// the nvidia driver, and don't use pthread will generate binaries that crash
// on launch. The only way to work around this issue is to do either:
//
//
// A: Specify 'no-as-needed' to the linker potentially causing over-linking
// and a slow down in link time.
//
// B: Use a method from pthread, making the linker realize that pthread is
// needed. Note we have to actually call the method so that a linker with
// optimizations enabled doesn't remove the function and pthread requirement.
//
//
// So that is the explanation on why we have the following function which is
// used once, doesn't look to be useful and seems very crazy.
#include <iostream>
#include <pthread.h>
#define VTKM_NVIDIA_PTHREAD_WORKAROUND 1
static int vtkm_force_linking_to_pthread_to_fix_nvidia_libgl_bug()
{
return static_cast<int>(pthread_self());
}
#endif
int UnitTestFancyTransferGLUT(int argc, char* argv[])
{
//get glut to construct a context for us
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowSize(1024, 1024);
glutCreateWindow("GLUT test");
//get glew to bind all the opengl functions
glewInit();
if (!glewIsSupported("GL_VERSION_2_1"))
{
std::cerr << glGetString(GL_RENDERER) << std::endl;
std::cerr << glGetString(GL_VERSION) << std::endl;
return 1;
}
#if defined(VTKM_NVIDIA_PTHREAD_WORKAROUND)
std::cout << ::vtkm_force_linking_to_pthread_to_fix_nvidia_libgl_bug();
#endif
return vtkm::interop::testing::TestingTransferFancyHandles::Run();
}