Added TARGET_HEADLESS option.

Toggles between using CGL/GLX/WGL (requiring running graphical desktop
environment) or EGL (without display attachment) for command-line
utilities and GL tests. Also exposed to the user through
MAGNUM_TARGET_HEADLESS CMake and preprocessor variables.

CMakeLists.txt

@@ -52,6 +52,7 @@ endif()
 
 cmake_dependent_option(TARGET_GLES2 "Build for OpenGL ES 2 / WebGL 1.0" ON "TARGET_GLES" OFF)
 cmake_dependent_option(TARGET_DESKTOP_GLES "Build for OpenGL ES on desktop" OFF "TARGET_GLES" OFF)
+option(TARGET_HEADLESS "Build command-line utilities for use on a headless machines" OFF)
 
 # Magnum Info (currently only using GLX, CGL, WGL/EGL on Windows or on NaCl)
 if(CORRADE_TARGET_UNIX OR CORRADE_TARGET_NACL OR CORRADE_TARGET_WINDOWS)
@@ -194,9 +195,15 @@ endif()
 if(TARGET_DESKTOP_GLES)
     set(MAGNUM_TARGET_DESKTOP_GLES 1)
 endif()
+if(TARGET_HEADLESS)
+    set(MAGNUM_TARGET_HEADLESS 1)
+endif()
 
 if(BUILD_GL_TESTS)
-    if(CORRADE_TARGET_APPLE)
+    if(MAGNUM_TARGET_HEADLESS)
+        set(WITH_WINDOWLESSEGLAPPLICATION ON)
+        set(GL_TEST_LIBRARIES Magnum MagnumWindowlessEglApplication)
+    elseif(CORRADE_TARGET_APPLE)
         set(WITH_WINDOWLESSCGLAPPLICATION ON)
         set(GL_TEST_LIBRARIES Magnum MagnumWindowlessCglApplication)
     elseif(CORRADE_TARGET_UNIX AND (NOT MAGNUM_TARGET_GLES OR MAGNUM_TARGET_DESKTOP_GLES))

doc/building.dox

@@ -167,6 +167,11 @@ available for desktop OpenGL only, see @ref requires-gl.
     `TARGET_GLES` is set.
 -   `TARGET_DESKTOP_GLES` -- Target OpenGL ES on desktop, i.e. use OpenGL ES
     emulation in desktop OpenGL library. Might not be supported in all drivers.
+-   `TARGET_HEADLESS` -- Build command-line utilities for use on a headless
+    machine. Basically it means that EGL with no display attachment is being
+    used everywhere instead of platform-specific toolkits like CGL, GLX or WGL.
+    Supported mainly on OpenGL ES drivers, for desktop OpenGL the only driver
+    that supports this configuration is NVidia >= 355.
 
 The features used can be conveniently detected in depending projects both in
 CMake and C++ sources, see @ref cmake and @ref Magnum/Magnum.h for more

doc/cmake.dox

@@ -183,7 +183,9 @@ are also available as preprocessor variables if including
 -   `MAGNUM_TARGET_GLES3` -- Defined if compiled for OpenGL ES 3.0
 -   `MAGNUM_TARGET_DESKTOP_GLES` -- Defined if compiled with OpenGL ES
     emulation on desktop OpenGL
--   `MAGNUM_TARGET_WEBGL` --- Defined if compiled for WebGL
+-   `MAGNUM_TARGET_WEBGL` -- Defined if compiled for WebGL
+-   `MAGNUM_TARGET_HEADLESS` -- Defined if compiled for headless machines. See
+    @ref MAGNUM_TARGET_HEADLESS documentation for more information.
 
 Workflows without imported targets are deprecated and the following variables
 are included just for backwards compatibility and only if

modules/FindMagnum.cmake

@@ -109,6 +109,7 @@
 #  MAGNUM_TARGET_DESKTOP_GLES   - Defined if compiled with OpenGL ES
 #   emulation on desktop OpenGL
 #  MAGNUM_TARGET_WEBGL          - Defined if compiled for WebGL
+#  MAGNUM_TARGET_HEADLESS       - Defined if compiled for headless machines
 #
 # Additionally these variables are defined for internal usage:
 #
@@ -207,7 +208,8 @@ set(_magnumFlags
     TARGET_GLES2
     TARGET_GLES3
     TARGET_DESKTOP_GLES
-    TARGET_WEBGL)
+    TARGET_WEBGL
+    TARGET_HEADLESS)
 foreach(_magnumFlag ${_magnumFlags})
     string(FIND "${_magnumConfigure}" "#define MAGNUM_${_magnumFlag}" _magnum_${_magnumFlag})
     if(NOT _magnum_${_magnumFlag} EQUAL -1)

src/Magnum/Magnum.h

@@ -143,6 +143,18 @@ which you might want to be aware of. Implies also @ref MAGNUM_TARGET_GLES and
 */
 #define MAGNUM_TARGET_WEBGL
 #undef MAGNUM_TARGET_WEBGL
+
+/**
+@brief Headless target
+
+Defined if the engine is built for use on a headless machine (without any
+graphical desktop environment). Basically it means that EGL with no display
+attachment is being used everywhere instead of platform-specific toolkits like
+CGL, GLX or WGL. Note that this might not be supported on all platforms, see
+@ref Platform::WindowlessEglApplication for more information.
+*/
+#define MAGNUM_TARGET_HEADLESS
+#undef MAGNUM_TARGET_HEADLESS
 #endif
 
 /** @{ @name Basic type definitions

src/Magnum/Platform/CMakeLists.txt

@@ -657,7 +657,9 @@ endif()
 if(WITH_MAGNUMINFO)
     add_executable(magnum-info magnum-info.cpp)
     target_link_libraries(magnum-info Magnum)
-    if(CORRADE_TARGET_APPLE)
+    if(MAGNUM_TARGET_HEADLESS)
+        target_link_libraries(magnum-info MagnumWindowlessEglApplication)
+    elseif(CORRADE_TARGET_APPLE)
         target_link_libraries(magnum-info MagnumWindowlessCglApplication)
     elseif(CORRADE_TARGET_NACL)
         target_link_libraries(magnum-info MagnumWindowlessNaClApplication)

src/Magnum/Platform/magnum-info.cpp

@@ -56,7 +56,9 @@
 #include "Magnum/TransformFeedback.h"
 #endif
 
-#ifdef CORRADE_TARGET_NACL
+#ifdef MAGNUM_TARGET_HEADLESS
+#include "Magnum/Platform/WindowlessEglApplication.h"
+#elif defined(CORRADE_TARGET_NACL)
 #include "Magnum/Platform/WindowlessNaClApplication.h"
 #elif defined(CORRADE_TARGET_APPLE)
 #include "Magnum/Platform/WindowlessCglApplication.h"
@@ -168,7 +170,9 @@ MagnumInfo::MagnumInfo(const Arguments& arguments): Platform::WindowlessApplicat
     Debug() << "  +---------------------------------------------------------+";
     Debug() << "";
 
-    #ifdef MAGNUM_WINDOWLESSNACLAPPLICATION_MAIN
+    #ifdef MAGNUM_WINDOWLESSEGLAPPLICATION_MAIN
+    Debug() << "Used application: Platform::WindowlessEglApplication";
+    #elif defined(MAGNUM_WINDOWLESSNACLAPPLICATION_MAIN)
     Debug() << "Used application: Platform::WindowlessNaClApplication";
     #elif defined(MAGNUM_WINDOWLESSCGLAPPLICATION_MAIN)
     Debug() << "Used application: Platform::WindowlessCglApplication";
@@ -245,6 +249,9 @@ MagnumInfo::MagnumInfo(const Arguments& arguments): Platform::WindowlessApplicat
     #ifdef MAGNUM_TARGET_WEBGL
     Debug() << "    MAGNUM_TARGET_WEBGL";
     #endif
+    #ifdef MAGNUM_TARGET_HEADLESS
+    Debug() << "    MAGNUM_TARGET_HEADLESS";
+    #endif
     Debug() << "";
 
     /* Create context here, so the context creation info is displayed at proper

src/Magnum/Test/AbstractOpenGLTester.h

@@ -32,7 +32,9 @@
 #include "Magnum/DebugOutput.h"
 #include "Magnum/Renderer.h"
 
-#if defined(CORRADE_TARGET_APPLE)
+#ifdef MAGNUM_TARGET_HEADLESS
+#include "Magnum/Platform/WindowlessEglApplication.h"
+#elif defined(CORRADE_TARGET_APPLE)
 #include "Magnum/Platform/WindowlessCglApplication.h"
 #elif defined(CORRADE_TARGET_UNIX) && (!defined(MAGNUM_TARGET_GLES) || defined(MAGNUM_TARGET_DESKTOP_GLES))
 #include "Magnum/Platform/WindowlessGlxApplication.h"

src/Magnum/Text/CMakeLists.txt

@@ -63,7 +63,9 @@ if(WITH_FONTCONVERTER)
     add_executable(magnum-fontconverter fontconverter.cpp)
     target_include_directories(magnum-fontconverter PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
     target_link_libraries(magnum-fontconverter Magnum MagnumText)
-    if(CORRADE_TARGET_APPLE)
+    if(MAGNUM_TARGET_HEADLESS)
+        target_link_libraries(magnum-fontconverter MagnumWindowlessEglApplication)
+    elseif(CORRADE_TARGET_APPLE)
         target_link_libraries(magnum-fontconverter MagnumWindowlessCglApplication)
     elseif(CORRADE_TARGET_UNIX AND NOT TARGET_GLES)
         target_link_libraries(magnum-fontconverter MagnumWindowlessGlxApplication)

src/Magnum/Text/fontconverter.cpp

@@ -32,7 +32,9 @@
 #include "Magnum/Text/DistanceFieldGlyphCache.h"
 #include "Magnum/Trade/AbstractImageConverter.h"
 
-#ifdef CORRADE_TARGET_APPLE
+#ifdef MAGNUM_TARGET_HEADLESS
+#include "Magnum/Platform/WindowlessEglApplication.h"
+#elif defined(CORRADE_TARGET_APPLE)
 #include "Magnum/Platform/WindowlessCglApplication.h"
 #elif defined(CORRADE_TARGET_UNIX)
 #include "Magnum/Platform/WindowlessGlxApplication.h"

src/Magnum/TextureTools/CMakeLists.txt

@@ -53,7 +53,9 @@ if(WITH_DISTANCEFIELDCONVERTER)
     add_executable(magnum-distancefieldconverter distancefieldconverter.cpp)
     target_include_directories(magnum-distancefieldconverter PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
     target_link_libraries(magnum-distancefieldconverter Magnum MagnumTextureTools)
-    if(CORRADE_TARGET_APPLE)
+    if(MAGNUM_TARGET_HEADLESS)
+        target_link_libraries(magnum-distancefieldconverter MagnumWindowlessEglApplication)
+    elseif(CORRADE_TARGET_APPLE)
         target_link_libraries(magnum-distancefieldconverter MagnumWindowlessCglApplication)
     elseif(CORRADE_TARGET_UNIX AND NOT TARGET_GLES)
         target_link_libraries(magnum-distancefieldconverter MagnumWindowlessGlxApplication)

src/Magnum/TextureTools/distancefieldconverter.cpp

@@ -38,7 +38,9 @@
 #include "Magnum/Trade/AbstractImageConverter.h"
 #include "Magnum/Trade/ImageData.h"
 
-#ifdef CORRADE_TARGET_APPLE
+#ifdef MAGNUM_TARGET_HEADLESS
+#include "Magnum/Platform/WindowlessEglApplication.h"
+#elif defined(CORRADE_TARGET_APPLE)
 #include "Magnum/Platform/WindowlessCglApplication.h"
 #elif defined(CORRADE_TARGET_UNIX)
 #include "Magnum/Platform/WindowlessGlxApplication.h"

src/Magnum/configure.h.cmake

@@ -30,3 +30,4 @@
 #cmakedefine MAGNUM_TARGET_GLES3
 #cmakedefine MAGNUM_TARGET_DESKTOP_GLES
 #cmakedefine MAGNUM_TARGET_WEBGL
+#cmakedefine MAGNUM_TARGET_HEADLESS