Subclass GLX (#1722)

application/testing/CMakeLists.txt

@@ -1,7 +1,7 @@
 # F3D Testing
 function(f3d_test)
 
-	cmake_parse_arguments(F3D_TEST "TONE_MAPPING;LONG_TIMEOUT;INTERACTION;INTERACTION_CONFIGURE;NO_BASELINE;NO_RENDER;NO_OUTPUT;WILL_FAIL;NO_DATA_FORCE_RENDER" "NAME;CONFIG;RESOLUTION;THRESHOLD;REGEXP;REGEXP_FAIL;HDRI;RENDERING_BACKEND" "DATA;DEPENDS;ARGS" ${ARGN})
+	cmake_parse_arguments(F3D_TEST "TONE_MAPPING;LONG_TIMEOUT;INTERACTION;INTERACTION_CONFIGURE;NO_BASELINE;NO_RENDER;NO_OUTPUT;WILL_FAIL;NO_DATA_FORCE_RENDER" "NAME;CONFIG;RESOLUTION;THRESHOLD;REGEXP;REGEXP_FAIL;HDRI;RENDERING_BACKEND" "DATA;DEPENDS;ENV;ARGS" ${ARGN})
 
   if(F3D_TEST_CONFIG)
     list(APPEND F3D_TEST_ARGS "--config=${F3D_TEST_CONFIG}")
@@ -118,6 +118,7 @@ function(f3d_test)
     set_tests_properties(f3d::${F3D_TEST_NAME} PROPERTIES FIXTURES_REQUIRED "${_depends_fixtures}")
   endif()
 
+  set(f3d_test_env_vars ${F3D_TEST_ENV})
   list(APPEND f3d_test_env_vars "CTEST_F3D_PROGRESS_BAR=1")
   if (F3D_TEST_NO_DATA_FORCE_RENDER)
     list(APPEND f3d_test_env_vars "CTEST_F3D_NO_DATA_FORCE_RENDER=1")
@@ -1029,7 +1030,9 @@ if(UNIX AND NOT APPLE AND VTK_VERSION VERSION_GREATER_EQUAL 9.3.20240914 AND F3D
 
   if(F3D_TESTING_ENABLE_GLX_TESTS)
     f3d_test(NAME TestRenderingBackendGLX DATA cow.vtp RENDERING_BACKEND glx)
-    f3d_test(NAME TestRenderingBackendGLXCheckClass DATA cow.vtp RENDERING_BACKEND glx ARGS --verbose REGEXP "vtkXOpenGLRenderWindow" NO_BASELINE)
+    f3d_test(NAME TestRenderingBackendGLXNoDisplay DATA cow.vtp RENDERING_BACKEND glx ENV "DISPLAY=:7" REGEXP "Cannot create a window" NO_BASELINE)
+    f3d_test(NAME TestRenderingBackendGLXCheckClass DATA cow.vtp RENDERING_BACKEND glx ARGS --verbose REGEXP "vtkF3DGLXRenderWindow" NO_BASELINE)
+    f3d_test(NAME TestRenderingBackendLinuxAutoCheckClass DATA cow.vtp ARGS --verbose REGEXP "vtkF3DGLXRenderWindow" NO_BASELINE)
   endif()
 
   f3d_test(NAME TestRenderingBackendWGLFailure DATA cow.vtp RENDERING_BACKEND wgl REGEXP "Cannot use a WGL context on this platform" NO_BASELINE)

library/src/context.cxx

@@ -7,10 +7,6 @@
 #include <vtkRenderingOpenGLConfigure.h>
 #include <vtkVersion.h>
 
-#if defined(VTK_USE_X) && VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
-#include <vtkglad/include/glad/glx.h>
-#endif
-
 #if defined(VTK_OPENGL_HAS_EGL) && VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
 #include <vtkglad/include/glad/egl.h>
 #endif
@@ -49,7 +45,6 @@ context::function context::getSymbol(const std::string& lib, const std::string&
 context::function context::glx()
 {
 #if defined(VTK_USE_X) && VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
-  gladLoaderLoadGLX(nullptr, 0); // Load core glx functions.
   return getSymbol("GLX", "glXGetProcAddress");
 #else
   throw loading_exception("Cannot use a GLX context on this platform");

library/src/window_impl.cxx

@@ -25,7 +25,7 @@
 #include <vtksys/SystemTools.hxx>
 
 #ifdef VTK_USE_X
-#include <vtkXOpenGLRenderWindow.h>
+#include <vtkF3DGLXRenderWindow.h>
 #endif
 
 #ifdef _WIN32
@@ -72,7 +72,15 @@ class window_impl::internals
 #ifdef _WIN32
     return vtkSmartPointer<vtkF3DWGLRenderWindow>::New();
 #else
-    // XXX: At the moment, rely on VTK logic for Linux and macOS
+#if defined(VTK_USE_X)
+    // try GLX
+    vtkSmartPointer<vtkRenderWindow> renWin = vtkSmartPointer<vtkF3DGLXRenderWindow>::New();
+    if (renWin)
+    {
+      return renWin;
+    }
+#endif
+    // XXX: At the moment, fallback on VTK logic
     // It will change in the future when other subclasses are implemented
     return vtkSmartPointer<vtkRenderWindow>::New();
 #endif
@@ -119,8 +127,8 @@ window_impl::window_impl(const options& options, const std::optional<Type>& type
   }
   else if (type == Type::GLX)
   {
-#if defined(VTK_USE_X) && VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
-    this->Internals->RenWin = vtkSmartPointer<vtkXOpenGLRenderWindow>::New();
+#if defined(VTK_USE_X)
+    this->Internals->RenWin = vtkSmartPointer<vtkF3DGLXRenderWindow>::New();
 #else
     throw engine::no_window_exception("Window type is GLX but VTK GLX support is not enabled");
 #endif
@@ -136,7 +144,10 @@ window_impl::window_impl(const options& options, const std::optional<Type>& type
     this->Internals->RenWin = internals::AutoBackendWindow();
   }
 
-  assert(this->Internals->RenWin != nullptr);
+  if (this->Internals->RenWin == nullptr)
+  {
+    throw engine::no_window_exception("Cannot create a window");
+  }
 
 #if VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
   vtkOpenGLRenderWindow* oglRenWin = vtkOpenGLRenderWindow::SafeDownCast(this->Internals->RenWin);
@@ -185,7 +196,7 @@ window_impl::Type window_impl::getType()
   }
 
 #ifdef VTK_USE_X
-  if (this->Internals->RenWin->IsA("vtkXOpenGLRenderWindow"))
+  if (this->Internals->RenWin->IsA("vtkF3DGLXRenderWindow"))
   {
     return Type::GLX;
   }

vtkext/private/module/CMakeLists.txt

@@ -66,6 +66,12 @@ if(WIN32)
   list(APPEND classes vtkF3DWin32OutputWindow vtkF3DWGLRenderWindow)
 endif()
 
+# In theory the test should be `if (VTK_USE_X)` but this variable is
+# only exported starting from VTK 9.4
+if(UNIX AND NOT APPLE AND NOT EMSCRIPTEN AND NOT ANDROID)
+  list(APPEND classes vtkF3DGLXRenderWindow)
+endif()
+
 if(ANDROID)
   list(APPEND classes vtkF3DAndroidLogOutputWindow)
 endif()

vtkext/private/module/vtkF3DGLXRenderWindow.cxx

@@ -0,0 +1,38 @@
+#include <vtkObjectFactory.h>
+#include <vtkVersion.h>
+
+#if VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
+#include <vtk_glad.h>
+#include <vtkglad/include/glad/glx.h>
+#else
+#include <vtk_glew.h>
+#endif
+
+#include "vtkF3DGLXRenderWindow.h"
+
+#include <X11/Xlib.h>
+
+//------------------------------------------------------------------------------
+vtkF3DGLXRenderWindow::vtkF3DGLXRenderWindow() = default;
+
+//------------------------------------------------------------------------------
+vtkF3DGLXRenderWindow::~vtkF3DGLXRenderWindow() = default;
+
+//------------------------------------------------------------------------------
+vtkF3DGLXRenderWindow* vtkF3DGLXRenderWindow::New()
+{
+  // Check if the X display is available
+  Display* dpy = XOpenDisplay(nullptr);
+  if (dpy == nullptr)
+  {
+    return nullptr;
+  }
+  XCloseDisplay(dpy);
+
+#if VTK_VERSION_NUMBER >= VTK_VERSION_CHECK(9, 3, 20240914)
+  // Load core glx functions
+  gladLoaderLoadGLX(nullptr, 0);
+#endif
+
+  VTK_STANDARD_NEW_BODY(vtkF3DGLXRenderWindow);
+}

vtkext/private/module/vtkF3DGLXRenderWindow.h

@@ -0,0 +1,25 @@
+/**
+ * @class   vtkF3DGLXRenderWindow
+ * @brief   GLX context render window
+ */
+
+#ifndef vtkF3DGLXRenderWindow_h
+#define vtkF3DGLXRenderWindow_h
+
+#include "vtkXOpenGLRenderWindow.h"
+
+class vtkF3DGLXRenderWindow : public vtkXOpenGLRenderWindow
+{
+public:
+  static vtkF3DGLXRenderWindow* New();
+  vtkTypeMacro(vtkF3DGLXRenderWindow, vtkXOpenGLRenderWindow);
+
+protected:
+  vtkF3DGLXRenderWindow();
+  ~vtkF3DGLXRenderWindow() override;
+
+private:
+  vtkF3DGLXRenderWindow(const vtkF3DGLXRenderWindow&) = delete;
+  void operator=(const vtkF3DGLXRenderWindow&) = delete;
+};
+#endif // vtkF3DGLXRenderWindow_h