CMake: build p3headlessgl display module

panda/metalibs/pandagl/CMakeLists.txt

@@ -17,11 +17,19 @@ elseif(HAVE_COCOA)
   set(PANDAGL_PIPE_TYPE "CocoaGLGraphicsPipe")
   set(PANDAGL_PIPE_INCLUDE "cocoaGLGraphicsPipe.h")
 
+elseif(HAVE_EGL)
+  list(APPEND PANDAGL_LINK_TARGETS p3egldisplay)
+  set(PANDAGL_PIPE_TYPE "eglGraphicsPipe")
+
+  if(HAVE_X11)
+    list(APPEND PANDAGL_LINK_TARGETS p3x11display)
+  endif()
+
 else()
   message("") # Add extra line before error
   message(SEND_ERROR
     "When compiling with OpenGL (HAVE_GL), at least one of:
-  HAVE_WGL, HAVE_COCOA, or HAVE_GLX must be defined.")
+  HAVE_WGL, HAVE_COCOA, HAVE_GLX, or HAVE_EGL must be defined.")
 
 endif()
 
@@ -42,4 +50,21 @@ install(TARGETS pandagl
   DESTINATION ${MODULE_DESTINATION}
   ARCHIVE COMPONENT OpenGLDevel)
 
+if(HAVE_EGL AND HAVE_GLX AND NOT WIN32 AND NOT APPLE)
+  # As a temporary solution for #1086, build this module, which we can use as a
+  # fallback to OpenGL for headless systems.
+  set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME "OpenGLDevel")
+  add_metalib(p3headlessgl ${MODULE_TYPE}
+    INCLUDE "eglGraphicsPipe.h"
+    INIT init_libpandagl pandagl.h
+    EXPORT int get_pipe_type_p3headlessgl "eglGraphicsPipe::get_class_type().get_index()"
+    COMPONENTS p3egldisplay_gl p3glgsg p3glstuff)
+  unset(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME)
+
+  install(TARGETS p3headlessgl
+    EXPORT OpenGL COMPONENT OpenGL
+    DESTINATION ${MODULE_DESTINATION}
+    ARCHIVE COMPONENT OpenGLDevel)
+endif()
+
 export_targets(OpenGL NAMESPACE "Panda3D::OpenGL::" COMPONENT OpenGLDevel)

panda/src/configfiles/CMakeLists.txt

@@ -5,6 +5,11 @@ if(HAVE_GL)
   set(AUX_DISPLAYS "${AUX_DISPLAYS}\naux-display pandagl")
 endif()
 
+if(HAVE_GL AND HAVE_EGL AND HAVE_GLX)
+  # Fallback for headless systems.
+  set(AUX_DISPLAYS "${AUX_DISPLAYS}\naux-display p3headlessgl")
+endif()
+
 if(HAVE_DX9)
   set(AUX_DISPLAYS "${AUX_DISPLAYS}\naux-display pandadx9")
 endif()

panda/src/egldisplay/CMakeLists.txt

@@ -1,8 +1,8 @@
-if(NOT HAVE_EGL OR NOT HAVE_X11)
+if(NOT HAVE_EGL)
   return()
 endif()
 
-if(NOT HAVE_GLES1 AND NOT HAVE_GLES2)
+if(NOT HAVE_GLES1 AND NOT HAVE_GLES2 AND NOT HAVE_GL)
   return()
 endif()
 
@@ -26,7 +26,33 @@ set(P3EGLDISPLAY_SOURCES
 
 composite_sources(p3egldisplay P3EGLDISPLAY_SOURCES)
 
-# We actually build this twice!  Once for GLES1, once for GLES2.
+# We actually build this thrice!  Once for GL, once for GLES1, once for GLES2.
+if(HAVE_GL AND NOT WIN32 AND NOT APPLE)
+  add_component_library(p3egldisplay_gl SYMBOL BUILDING_PANDAGL
+    INIT init_libegldisplay config_egldisplay.h
+    ${P3EGLDISPLAY_HEADERS} ${P3EGLDISPLAY_SOURCES})
+  target_link_libraries(p3egldisplay_gl p3glgsg
+    PKG::EGL PKG::GL)
+
+  if(HAVE_X11 AND NOT HAVE_GLX)
+    target_link_librarise(p3egldisplay_gl p3x11display)
+    target_compile_definitions(p3egldisplay_gl PUBLIC USE_X11)
+  else()
+    target_compile_definitions(p3egldisplay_gl PRIVATE EGL_NO_X11)
+  endif()
+
+  if(NOT BUILD_METALIBS)
+    install(TARGETS p3egldisplay_gl
+      EXPORT OpenGL COMPONENT OpenGL
+      DESTINATION ${CMAKE_INSTALL_LIBDIR}
+      RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+      INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/panda3d
+      ARCHIVE COMPONENT OpenGLDevel)
+  endif()
+
+  install(FILES ${P3EGLDISPLAY_HEADERS} COMPONENT OpenGLDevel DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/panda3d)
+endif()
+
 if(HAVE_GLES1)
   add_component_library(p3egldisplay_gles1 SYMBOL BUILDING_PANDAGLES
     INIT init_libegldisplay config_egldisplay.h