Added MAGNUM_ASSERT_{VERSION,EXTENSION}_SUPPORTED() macros.

src/Context.cpp

@@ -35,26 +35,26 @@ namespace Magnum {
 
 Debug operator<<(Debug debug, Version value) {
     switch(value) {
-        #define _c(value) case Version::value: return debug << "Version::" #value;
-        _c(None)
+        #define _c(value, string) case Version::value: return debug << string;
+        _c(None, "None")
         #ifndef MAGNUM_TARGET_GLES
-        _c(GL210)
-        _c(GL300)
-        _c(GL310)
-        _c(GL320)
-        _c(GL330)
-        _c(GL400)
-        _c(GL410)
-        _c(GL420)
-        _c(GL430)
+        _c(GL210, "OpenGL 2.1")
+        _c(GL300, "OpenGL 3.0")
+        _c(GL310, "OpenGL 3.1")
+        _c(GL320, "OpenGL 3.2")
+        _c(GL330, "OpenGL 3.3")
+        _c(GL400, "OpenGL 4.0")
+        _c(GL410, "OpenGL 4.1")
+        _c(GL420, "OpenGL 4.2")
+        _c(GL430, "OpenGL 4.3")
         #else
-        _c(GLES200)
-        _c(GLES300)
+        _c(GLES200, "OpenGL ES 2.0")
+        _c(GLES300, "OpenGL ES 3.0")
         #endif
         #undef _c
     }
 
-    return debug << "Version::(invalid)";
+    return debug << "Invalid";
 }
 
 const std::vector<Extension>& Extension::extensions(Version version) {

src/Context.h

@@ -16,7 +16,7 @@
 */
 
 /** @file
- * @brief Enum Version, class Magnum::Context, Magnum::Extension
+ * @brief Enum Version, class Magnum::Context, Magnum::Extension, macro MAGNUM_ASSERT_VERSION_SUPPORTED(), MAGNUM_ASSERT_EXTENSION_SUPPORTED()
  */
 
 #include <bitset>
@@ -34,7 +34,11 @@ namespace Implementation {
 }
 #endif
 
-/** @brief OpenGL version */
+/**
+@brief OpenGL version
+
+@see Context, MAGNUM_ASSERT_VERSION_SUPPORTED()
+*/
 enum class Version: GLint {
     None = 0xFFFF,                  /**< @brief Unspecified */
     #ifndef MAGNUM_TARGET_GLES
@@ -200,7 +204,7 @@ class MAGNUM_EXPORT Context {
         /**
          * @brief Whether given OpenGL version is supported
          *
-         * @see supportedVersion()
+         * @see supportedVersion(), MAGNUM_ASSERT_VERSION_SUPPORTED()
          */
         inline bool isVersionSupported(Version version) const {
             return _version >= version;
@@ -235,7 +239,8 @@ class MAGNUM_EXPORT Context {
          * }
          * @endcode
          *
-         * @see isExtensionSupported(const Extension&) const
+         * @see isExtensionSupported(const Extension&) const,
+         *      MAGNUM_ASSERT_EXTENSION_SUPPORTED()
          */
         template<class T> inline bool isExtensionSupported() const {
             return isVersionSupported(T::coreVersion()) || (isVersionSupported(T::requiredVersion()) && extensionStatus[T::Index]);
@@ -248,7 +253,8 @@ class MAGNUM_EXPORT Context {
          * hardware, but for general usage prefer isExtensionSupported() const,
          * as it does most operations in compile time.
          *
-         * @see supportedExtensions(), Extension::extensions()
+         * @see supportedExtensions(), Extension::extensions(),
+         *      MAGNUM_ASSERT_EXTENSION_SUPPORTED()
          */
         inline bool isExtensionSupported(const Extension& extension) const {
             return isVersionSupported(extension._coreVersion) || (isVersionSupported(extension._requiredVersion) && extensionStatus[extension._index]);
@@ -271,6 +277,65 @@ class MAGNUM_EXPORT Context {
         Implementation::State* _state;
 };
 
+/** @hideinitializer
+@brief Assert that given OpenGL version is supported
+@param version      Version
+
+Useful for initial checks on availability of required features.
+
+By default, if assertion fails, an message is printed to error output and the
+application exits with value `-3`. If `CORRADE_NO_ASSERT` is defined, this
+macro does nothing. Example usage:
+@code
+MAGNUM_ASSERT_VERSION_SUPPORTED(Version::GL330);
+@endcode
+
+@see @ref Magnum::Context::isVersionSupported() "Context::isVersionSupported()",
+    MAGNUM_ASSERT_EXTENSION_SUPPORTED(), CORRADE_ASSERT(),
+    CORRADE_INTERNAL_ASSERT()
+*/
+#ifdef CORRADE_NO_ASSERT
+#define MAGNUM_ASSERT_VERSION_SUPPORTED(version) do {} while(0)
+#else
+#define MAGNUM_ASSERT_VERSION_SUPPORTED(version)                            \
+    do {                                                                    \
+        if(!Context::current()->isVersionSupported(version)) {    \
+            Corrade::Utility::Error() << "Magnum: required version" << version << "is not supported"; \
+            exit(-3);                                                       \
+        }                                                                   \
+    } while(0)
+#endif
+
+/** @hideinitializer
+@brief Assert that given OpenGL extension is supported
+@param extension    Extension name (from @ref Magnum::Extensions "Extensions"
+    namespace)
+
+Useful for initial checks on availability of required features.
+
+By default, if assertion fails, an message is printed to error output and the
+application exits with value `-3`. If `CORRADE_NO_ASSERT` is defined, this
+macro does nothing. Example usage:
+@code
+MAGNUM_ASSERT_EXTENSION_SUPPORTED(Extensions::GL::ARB::geometry_shader4);
+@endcode
+
+@see @ref Magnum::Context::isExtensionSupported() "Context::isExtensionSupported()",
+    MAGNUM_ASSERT_VERSION_SUPPORTED(), CORRADE_ASSERT(),
+    CORRADE_INTERNAL_ASSERT()
+*/
+#ifdef CORRADE_NO_ASSERT
+#define MAGNUM_ASSERT_EXTENSION_SUPPORTED(extension) do {} while(0)
+#else
+#define MAGNUM_ASSERT_EXTENSION_SUPPORTED(extension)                        \
+    do {                                                                    \
+        if(!Context::current()->isExtensionSupported<extension>()) { \
+            Corrade::Utility::Error() << "Magnum: required extension" << extension::string() << "is not supported"; \
+            exit(-3);                                                       \
+        }                                                                   \
+    } while(0)
+#endif
+
 }
 
 #endif

src/Extensions.h

@@ -33,6 +33,8 @@ and string(), but these structs are better suited for compile-time decisions
 rather than Extension instances. See Context::isExtensionSupported() for
 example usage.
 
+@see MAGNUM_ASSERT_EXTENSION_SUPPORTED()
+
 @todo Manual indices for extensions, this has gaps
 @todo Unhide ES2_compatibility, ES3_compatibility on ES
 @todo Add ES and GL 4.3 extensions