Audio: Add Extensions.h

Analog to Magnum::Extensions, but without Version, since OpenAL has only
one Version which is in use (OpenAL 1.1).

Signed-off-by: Squareys <Squareys@googlemail.com>

src/Magnum/Audio/CMakeLists.txt

@@ -40,6 +40,7 @@ set(MagnumAudio_HEADERS
     Audio.h
     Buffer.h
     Context.h
+    Extensions.h
     Renderer.h
     Source.h
 

src/Magnum/Audio/Extensions.h

@@ -0,0 +1,89 @@
+#ifndef Magnum_Audio_Extensions_h
+#define Magnum_Audio_Extensions_h
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015
+              Vladimír Vondruš <mosra@centrum.cz>
+    Copyright © 2015 Jonathan Hale <squareys@googlemail.com>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+/** @file
+ * @brief Namespace @ref Magnum::Audio::Extensions
+ */
+
+#include "MagnumExternal/OpenAL/extensions.h"
+
+namespace Magnum { namespace Audio {
+
+/**
+@brief Compile-time information about OpenAL extensions
+
+Each extension is `struct` named hierarchically by prefix, vendor and
+extension name taken from list at @ref openal-support, for example
+`ALC::SOFTX::HRTF`.
+
+Each struct has the same public methods as @ref Extension class
+(@ref Extension::requiredVersion() "requiredVersion()",
+@ref Extension::coreVersion() "coreVersion()" and @ref Extension::string() "string()"),
+but these structs are better suited for compile-time decisions rather than
+@ref Extension instances. See @ref Context::isExtensionSupported() for example
+usage.
+
+This namespace is not built by default. It is built if `WITH_AUDIO` is
+enabled when building Magnum. To use this library, you need to request
+`Audio` component of `Magnum` package in CMake, add `${MAGNUM_AUDIO_INCLUDE_DIRS}`
+to include path and link to `${MAGNUM_AUDIO_LIBRARIES}`. See @ref building and
+@ref cmake for more information. Additional plugins are enabled separately, see
+particular `*Importer` class documentation, @ref building-plugins,
+@ref cmake-plugins and @ref plugins for more information.
+@see @ref MAGNUM_ASSERT_AUDIO_EXTENSION_SUPPORTED()
+@todo Manual indices for extensions, this has gaps
+*/
+namespace Extensions {
+
+#ifndef DOXYGEN_GENERATING_OUTPUT
+#define _extension(prefix, vendor, extension) \
+    struct extension {                                                      \
+        enum: std::size_t { Index = __LINE__-1 };                                \
+        constexpr static const char* string() { return #prefix "_" #vendor "_" #extension; } \
+    };
+
+/* IMPORTANT: don't forget to add new extensions also in Context.cpp */
+namespace AL {
+    #line 1
+    namespace EXT {
+        _extension(AL,EXT,FLOAT32) // #???
+        _extension(AL,EXT,DOUBLE) // #???
+    }
+} namespace ALC {
+    namespace SOFTX {
+        _extension(ALC,SOFTX,HRTF) // #???
+    }
+}
+#undef _extension
+#endif
+
+}
+
+}}
+
+#endif