Add is_version_at_least function

Reorder functions in extension.* more logically

diff --git a/source/extension.cpp b/source/extension.cpp
index 9ed1777914b9076c89f8c55ba58f0a6012ca54db..bab160d5196fe71519f8fbeca3e2680f9bbc1032 100644 (file)
--- a/source/extension.cpp
+++ b/source/extension.cpp
@@ -60,6 +60,12 @@ bool is_supported(const string &ext)
        return extensions.count(ext);
 }
 
+void require_extension(const string &ext)
+{
+       if(!is_supported(ext))
+               throw UnsupportedExtension(ext);
+}
+
 const Version &get_gl_version()
 {
        static Version version;
@@ -84,16 +90,15 @@ const Version &get_gl_version()
        return version;
 }
 
-void require_extension(const string &ext)
+bool is_version_at_least(unsigned a, unsigned b)
 {
-       if(!is_supported(ext))
-               throw UnsupportedExtension(ext);
+       const Version &ver = get_gl_version();
+       return (ver.major>a || (ver.major==a && ver.minor>=b));
 }
 
 void require_version(unsigned a, unsigned b)
 {
-       const Version &ver = get_gl_version();
-       if(ver.major<a || (ver.major==a && ver.minor<b))
+       if(!is_version_at_least(a, b))
                throw UnsupportedExtension(format("OpenGL %d.%d", a, b));
 }
 

diff --git a/source/extension.h b/source/extension.h
index 4410cc3c316e244ec7ecd934e4668befffb6126d..ed2530a922fdf5c7ae3de64a29d4de3e693d0d62 100644 (file)
--- a/source/extension.h
+++ b/source/extension.h
@@ -1,7 +1,7 @@
 /* $Id$
 
 This file is part of libmspgl
-Copyright © 2007  Mikko Rasa, Mikkosoft Productions
+Copyright © 2007-2008, 2010  Mikko Rasa, Mikkosoft Productions
 Distributed under the LGPL
 */
 
@@ -27,12 +27,6 @@ functions of that extension are safe to use.
 */
 bool is_supported(const std::string &);
 
-/**
-Returns the OpenGL version number, as reported by the implementation.
-Functions up to the returned version are safe to use.
-*/
-const Version &get_gl_version();
-
 /**
 Checks that an extension is supported and throws if it isn't.
 */
@@ -46,6 +40,17 @@ struct RequireExtension
        RequireExtension(const std::string &e) { require_extension(e); }
 };
 
+/**
+Returns the OpenGL version number, as reported by the implementation.
+Functions up to the returned version are safe to use.
+*/
+const Version &get_gl_version();
+
+/**
+Indicates whether the OpenGL version is at least a.b.
+*/
+bool is_version_at_least(unsigned a, unsigned b);
+
 /**
 Checks that the OpenGL version is at least a.b and throws if it isn't.
 */
@@ -60,7 +65,7 @@ struct RequireVersion
 };
 
 /**
-Returns the address of an extension function.
+Returns the address of an extension function.  Only indended for internal use.
 */
 ExtFunc *get_proc_address(const std::string &);