Replace GLX with EGL for X11

cmake/Findepoxy.cmake

@@ -0,0 +1,84 @@
+# SPDX-FileCopyrightText: 2014 Fredrik Höglund <[email protected]>
+# SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <[email protected]>
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+#[=======================================================================[.rst:
+Findepoxy
+---------
+
+Try to find libepoxy on a Unix system.
+
+This will define the following variables:
+
+``epoxy_FOUND``
+    True if (the requested version of) libepoxy is available
+``epoxy_VERSION``
+    The version of libepoxy
+``epoxy_LIBRARIES``
+    This should be passed to target_link_libraries() if the target is not
+    used for linking
+``epoxy_INCLUDE_DIRS``
+    This should be passed to target_include_directories() if the target is not
+    used for linking
+``epoxy_DEFINITIONS``
+    This should be passed to target_compile_options() if the target is not
+    used for linking
+``epoxy_HAS_GLX``
+    True if GLX support is available
+
+If ``epoxy_FOUND`` is TRUE, it will also define the following imported target:
+
+``epoxy::epoxy``
+    The epoxy library
+
+In general we recommend using the imported target, as it is easier to use.
+Bear in mind, however, that if the target is in the link interface of an
+exported library, it must be made available by the package config file.
+#]=======================================================================]
+
+find_package(PkgConfig QUIET)
+pkg_check_modules(PKG_epoxy QUIET epoxy)
+
+set(epoxy_VERSION ${PKG_epoxy_VERSION})
+set(epoxy_DEFINITIONS ${PKG_epoxy_CFLAGS})
+
+find_path(epoxy_INCLUDE_DIRS
+    NAMES epoxy/gl.h
+    HINTS ${PKG_epoxy_INCLUDEDIR} ${PKG_epoxy_INCLUDE_DIRS}
+)
+find_library(epoxy_LIBRARIES
+    NAMES epoxy
+    HINTS ${PKG_epoxy_LIBDIR} ${PKG_epoxy_LIBRARY_DIRS}
+)
+find_file(epoxy_GLX_HEADER NAMES epoxy/glx.h HINTS ${epoxy_INCLUDE_DIR})
+
+if (epoxy_GLX_HEADER STREQUAL "epoxy_GLX_HEADER-NOTFOUND")
+    set(epoxy_HAS_GLX FALSE CACHE BOOL "whether glx is available")
+else ()
+    set(epoxy_HAS_GLX TRUE CACHE BOOL "whether glx is available")
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(epoxy
+    FOUND_VAR epoxy_FOUND
+    REQUIRED_VARS epoxy_LIBRARIES epoxy_INCLUDE_DIRS
+    VERSION_VAR epoxy_VERSION
+)
+
+if (epoxy_FOUND AND NOT TARGET epoxy::epoxy)
+    add_library(epoxy::epoxy UNKNOWN IMPORTED)
+    set_target_properties(epoxy::epoxy PROPERTIES
+        IMPORTED_LOCATION "${epoxy_LIBRARIES}"
+        INTERFACE_COMPILE_OPTIONS "${epoxy_DEFINITIONS}"
+        INTERFACE_INCLUDE_DIRECTORIES "${epoxy_INCLUDE_DIRS}"
+    )
+endif()
+
+mark_as_advanced(
+    epoxy_DEFINITIONS
+    epoxy_HAS_GLX
+    epoxy_INCLUDE_DIRS
+    epoxy_LIBRARIES
+    epoxy_VERSION
+)

components/pango_display/src/display.cpp

@@ -152,7 +152,9 @@ WindowInterface& CreateWindowAndBind(std::string window_title, int w, int h, con
     }
 
     context->MakeCurrent();
+#ifdef HAVE_GLEW
     glewInit();
+#endif
 
     // And finally process pending window events (such as resize) now that we've setup our callbacks.
     context->window->ProcessEvents();

components/pango_opengl/CMakeLists.txt

@@ -24,7 +24,7 @@ PRIVATE
 
 find_package(Eigen3 REQUIRED NO_MODULE)
 message(STATUS "Found Eigen: '${EIGEN3_INCLUDE_DIRS}'")
-target_compile_definitions(${COMPONENT} PUBLIC HAVE_EIGEN HAVE_GLEW)
+target_compile_definitions(${COMPONENT} PUBLIC HAVE_EIGEN)
 
 set_target_properties(
     ${COMPONENT} PROPERTIES VERSION ${PANGOLIN_VERSION} SOVERSION ${PANGOLIN_VERSION_MAJOR}
@@ -40,19 +40,25 @@ install(DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/include"
 )
 
 if(EMSCRIPTEN)
-    target_compile_definitions(${COMPONENT} PUBLIC HAVE_GLES HAVE_GLES_2)
+    target_compile_definitions(${COMPONENT} PUBLIC HAVE_GLES HAVE_GLES_2 HAVE_GLEW)
     target_sources( ${COMPONENT} PRIVATE ${CMAKE_CURRENT_LIST_DIR}/src/compat/gl2engine.cpp)
 else()
     if(_LINUX_)
+        # EGL specific
         set(OpenGL_GL_PREFERENCE "GLVND")
+        find_package(OpenGL REQUIRED COMPONENTS OpenGL EGL)
+        find_package(epoxy REQUIRED)
+        target_link_libraries(${COMPONENT} PUBLIC epoxy::epoxy OpenGL::EGL)
+        target_include_directories(${COMPONENT} PUBLIC $<BUILD_INTERFACE:${OPENGL_EGL_INCLUDE_DIRS}>)
+        target_compile_definitions(${COMPONENT} PUBLIC HAVE_EPOXY)
+    else()
+        # OpenGL defaults
+        find_package(OpenGL REQUIRED)
+        find_package(GLEW REQUIRED)
+        target_include_directories(${COMPONENT} PUBLIC $<BUILD_INTERFACE:${GLEW_INCLUDE_DIR}>)
+        target_link_libraries(${COMPONENT} PUBLIC ${GLEW_LIBRARY})
+        target_link_libraries(${COMPONENT} PUBLIC ${OPENGL_LIBRARIES})
+        target_include_directories(${COMPONENT} PUBLIC $<BUILD_INTERFACE:${OPENGL_INCLUDE_DIR}>)
+        target_compile_definitions(${COMPONENT} PUBLIC HAVE_GLEW)
     endif()
-    find_package(OpenGL REQUIRED QUIET)
-    find_package(GLEW REQUIRED QUIET)
-    target_include_directories( ${COMPONENT} PUBLIC
-        $<BUILD_INTERFACE:${OPENGL_INCLUDE_DIR}>
-        $<BUILD_INTERFACE:${GLEW_INCLUDE_DIR}>
-    )
-    target_link_libraries( ${COMPONENT} PUBLIC
-        ${GLEW_LIBRARY} ${OPENGL_LIBRARIES}
-    )
 endif()

components/pango_opengl/include/pangolin/gl/glplatform.h

@@ -55,8 +55,10 @@
     #undef ERROR
 #endif
 
-#ifdef HAVE_GLEW
+#if defined(HAVE_GLEW)
     #include <GL/glew.h>
+#elif defined(HAVE_EPOXY)
+    #include <epoxy/gl.h>
 #endif
 
 #ifdef HAVE_GLES

components/pango_windowing/CMakeLists.txt

@@ -24,10 +24,12 @@ elseif(EMSCRIPTEN)
     PangolinRegisterFactory(WindowInterface EmscriptenWindow)
 else()
     find_package(X11 QUIET)
-    if(X11_FOUND)
+    find_package(OpenGL QUIET COMPONENTS EGL)
+    if(X11_FOUND AND OpenGL_EGL_FOUND)
         target_sources( ${COMPONENT} PRIVATE ${CMAKE_CURRENT_LIST_DIR}/src/display_x11.cpp )
         target_link_libraries(${COMPONENT} PRIVATE ${X11_LIBRARIES} )
         target_include_directories(${COMPONENT} PRIVATE ${X11_INCLUDE_DIR} )
+        target_link_libraries(${COMPONENT} PRIVATE OpenGL::EGL)
         PangolinRegisterFactory(WindowInterface X11Window)
     endif()
 

components/pango_windowing/include/pangolin/windowing/X11Window.h

@@ -34,7 +34,7 @@
 #include <string>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
-#include <GL/glx.h>
+#include <EGL/egl.h>
 
 namespace pangolin
 {
@@ -59,22 +59,23 @@ struct X11Display
 
 struct X11GlContext : public GlContextInterface
 {
-    X11GlContext(std::shared_ptr<X11Display> &d, ::GLXFBConfig chosenFbc, std::shared_ptr<X11GlContext> shared_context = std::shared_ptr<X11GlContext>() );
+    X11GlContext(std::shared_ptr<X11Display> &d);
     ~X11GlContext();
 
     std::shared_ptr<X11Display> display;
 
-    std::shared_ptr<X11GlContext> shared_context;
-
     // Owns the OpenGl Context
-    ::GLXContext glcontext;
+    EGLContext egl_context;
+    EGLDisplay egl_display;
+    EGLConfig egl_config;
+    EGLSurface egl_surface;
 };
 
 struct X11Window : public WindowInterface
 {
     X11Window(
         const std::string& title, int width, int height,
-        std::shared_ptr<X11Display>& display, ::GLXFBConfig chosenFbc
+        std::shared_ptr<X11Display>& display, std::shared_ptr<X11GlContext> newglcontext
     );
 
     ~X11Window();
@@ -85,7 +86,7 @@ struct X11Window : public WindowInterface
 
     void Resize(unsigned int w, unsigned int h) override;
 
-    void MakeCurrent(GLXContext ctx);
+    void MakeCurrent(EGLContext ctx);
 
     void MakeCurrent() override;
 

components/pango_windowing/src/display_wayland.cpp

@@ -853,8 +853,6 @@ static const struct wl_registry_listener wregistry_listener = {
 };
 
 WaylandDisplay::WaylandDisplay() {
-    xkb_context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
-
     wdisplay = wl_display_connect(nullptr);
     if (wdisplay == nullptr) {
         throw std::runtime_error("Cannot connect to Wayland compositor!");
@@ -865,6 +863,8 @@ WaylandDisplay::WaylandDisplay() {
 
     wl_display_roundtrip(wdisplay);
 
+    xkb_context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
+
     egl_display = eglGetDisplay((EGLNativeDisplayType)wdisplay);
     if(!egl_display) {
         std::cerr << "Failed to open EGL display" << std::endl;