More clean up for synch with 0.8.42

src/osg/GLExtensions.cpp

@@ -0,0 +1,74 @@
+#ifdef _WIN32
+#include <windows.h>
+#elif !defined macintosh
+#include <dlfcn.h>
+#endif
+
+#include "osg/GL"
+#include "osg/GLExtensions"
+#include "osg/Notify"
+
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <string>
+#include <vector>
+#include <set>
+
+const bool osg::isGLExtensionSupported(const char *extension)
+{
+    typedef std::set<std::string>  ExtensionSet;
+    static ExtensionSet s_extensionSet;
+    static const char* s_extensions = NULL;
+    if (s_extensions==NULL)
+    {
+        // get the extension list from OpenGL.
+        s_extensions = (const char*)glGetString(GL_EXTENSIONS);
+        if (s_extensions==NULL) return false;
+
+        // insert the ' ' delimiated extensions words into the extensionSet.
+        const char *startOfWord = s_extensions;
+        const char *endOfWord;
+        while ((endOfWord = strchr(startOfWord,' '))!=NULL)
+        {
+            s_extensionSet.insert(std::string(startOfWord,endOfWord));
+            startOfWord = endOfWord+1;
+        }
+        if (*startOfWord!=0) s_extensionSet.insert(std::string(startOfWord));
+        
+        osg::notify(INFO)<<"OpenGL extensions supported by installed OpenGL drivers are:"<<endl;
+        for(ExtensionSet::iterator itr=s_extensionSet.begin();
+            itr!=s_extensionSet.end();
+            ++itr)
+        {
+            osg::notify(INFO)<<"    "<<*itr<<endl;
+        }
+            
+    }
+
+    // true if extension found in extensionSet.
+    bool result = s_extensionSet.find(extension)!=s_extensionSet.end();
+
+    if (result) osg::notify(INFO)<<"OpenGL extension '"<<extension<<"' is supported."<<endl;
+    else osg::notify(INFO)<<"OpenGL extension '"<<extension<<"' is not supported."<<endl;
+
+    return result;
+}
+
+
+void* osg::getGLExtensionFuncPtr(const char *funcName)
+{
+#if defined(_WIN32)
+   return wglGetProcAddress(funcName);
+#elif defined(macintosh)
+   return NULL;
+#else
+   static void *lib = dlopen("libGL.so", RTLD_LAZY);
+   if (lib)
+      return dlsym(lib, funcName);
+   else
+      return NULL;
+#endif
+}