Platform: add Sdl2Application::Configuration::WindowFlag::{OpenGL,Vulkan}.

doc/changelog.dox

@@ -298,6 +298,10 @@ See also:
     in @ref Platform::GlfwApplication and @ref Platform::EmscriptenApplication)
     for changing window title at runtime as opposed to setting them on
     application startup
+-   Added @ref Platform::Sdl2Application::Configuration::WindowFlag::OpenGL and
+    @ref Platform::Sdl2Application::Configuration::WindowFlag::Vulkan "WindowFlag::Vulkan",
+    meant to be used together with @ref Platform::Sdl2Application::Configuration::WindowFlag::Contextless for
+    manual creation of OpenGL contexts and Vulkan instances
 -   @ref Platform::WindowlessEglApplication now uses the
     @m_class{m-doc-external} [EGL_EXT_device_enumeration](https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_device_enumeration.txt),
     @m_class{m-doc-external} [EGL_EXT_platform_base](https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_platform_base.txt) and

src/Magnum/Platform/Sdl2Application.cpp

@@ -295,7 +295,7 @@ bool Sdl2Application::tryCreate(const Configuration& configuration) {
         #endif
         SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
         scaledWindowSize.x(), scaledWindowSize.y(),
-        SDL_WINDOW_ALLOW_HIGHDPI|Uint32(configuration.windowFlags() & ~Configuration::WindowFlag::Contextless))))
+        SDL_WINDOW_ALLOW_HIGHDPI|SDL_WINDOW_OPENGL|Uint32(configuration.windowFlags() & ~Configuration::WindowFlag::Contextless))))
     {
         Error() << "Platform::Sdl2Application::tryCreate(): cannot create window:" << SDL_GetError();
         return false;

src/Magnum/Platform/Sdl2Application.h

@@ -1415,7 +1415,28 @@ class Sdl2Application::Configuration {
              * @ref tryCreate(const Configuration&) to prevent implicit
              * creation of an OpenGL context.
              */
-            Contextless = 1u << 31 /* Hope this won't ever conflict with anything */
+            Contextless = 1u << 31, /* Hope this won't ever conflict with anything */
+
+            /**
+             * Request a window for use with OpenGL. Useful in combination with
+             * @ref WindowFlag::Contextless, otherwise enabled implicitly when
+             * creating an OpenGL context using @ref Sdl2Application(const Arguments&),
+             * @ref Sdl2Application(const Arguments, const Configuration&, const GLConfiguration&),
+             * @ref create(const Configuration&, const GLConfiguration&) or
+             * @ref tryCreate(const Configuration&, const GLConfiguration&).
+             */
+            OpenGL = SDL_WINDOW_OPENGL,
+
+            #if !defined(CORRADE_TARGET_EMSCRIPTEN) && (SDL_MAJOR_VERSION*1000 + SDL_MINOR_VERSION*100 + SDL_PATCHLEVEL >= 2006 || defined(DOXYGEN_GENERATING_OUTPUT))
+            /**
+             * Request a window for use with Vulkan. Useful in combination with
+             * @ref WindowFlag::Contextless.
+             *
+             * @note Available since SDL 2.0.6, not available on
+             *      @ref CORRADE_TARGET_EMSCRIPTEN "Emscripten".
+             */
+            Vulkan = SDL_WINDOW_VULKAN
+            #endif
         };
 
         /**
@@ -1429,7 +1450,10 @@ class Sdl2Application::Configuration {
             SDL_WINDOW_FULLSCREEN|SDL_WINDOW_BORDERLESS|SDL_WINDOW_HIDDEN|
             SDL_WINDOW_MAXIMIZED|SDL_WINDOW_MINIMIZED|SDL_WINDOW_INPUT_GRABBED|
             #endif
-            Uint32(WindowFlag::Contextless)
+            Uint32(WindowFlag::Contextless)|SDL_WINDOW_OPENGL
+            #if !defined(CORRADE_TARGET_EMSCRIPTEN) && SDL_MAJOR_VERSION*1000 + SDL_MINOR_VERSION*100 + SDL_PATCHLEVEL >= 2006
+            |SDL_WINDOW_VULKAN
+            #endif
             > WindowFlags;
         #else
         typedef Containers::EnumSet<WindowFlag> WindowFlags;