MSVC and Apple OS X fixes

simgear/screen/extensions.cxx

@@ -26,9 +26,11 @@
 
 #ifndef WIN32
 #include <dlfcn.h>
+#else
+#include <windows.h>
 #endif
 
-#include <extensions.hxx>
+#include "extensions.hxx"
 
 bool SGSearchExtensionsString(char *extString, char *extName) {
     // Returns GL_TRUE if the *extName string appears in the *extString string,
@@ -64,3 +66,37 @@ bool SGIsOpenGLExtensionSupported(char *extName) {
 extName);
 }
 
+#ifdef __APPLE__
+
+#include <CoreFoundation/CoreFoundation.h>
+
+void* macosxGetGLProcAddress(const char *func) {
+
+  /* We may want to cache the bundleRef at some point */
+  static CFBundleRef bundle = 0;
+
+  if (!bundle) {
+
+    CFURLRef bundleURL = CFURLCreateWithFileSystemPath (kCFAllocatorDefault,
+							CFSTR("/System/Library/Frameworks/OpenGL.framework"), kCFURLPOSIXPathStyle, true);
+
+    bundle = CFBundleCreate (kCFAllocatorDefault, bundleURL);
+    CFRelease (bundleURL);
+  }
+
+  if (!bundle)
+    return 0;
+
+  CFStringRef functionName = CFStringCreateWithCString
+    (kCFAllocatorDefault, func, kCFStringEncodingASCII);
+  
+  void *function;
+  
+  function = CFBundleGetFunctionPointerForName (bundle, functionName);
+
+  CFRelease (functionName);
+
+  return function;
+}
+
+#endif

simgear/screen/extensions.hxx

@@ -37,11 +37,18 @@ extern "C" {
 static bool SGSearchExtensionsString(char *extString, char *extName);
 bool SGIsOpenGLExtensionSupported(char *extName);
 
+#ifdef __APPLE__
+  // don't use an inline function for symbol lookup, since it is too big
+  void* macosxGetGLProcAddress(const char *func);
+#endif
+
 inline void (*SGLookupFunction(const char *func))() {
 
 #if defined( WIN32 )
         return (void (*)()) wglGetProcAddress(func);
 
+#elif defined( __APPLE__ )
+	return (void (*)()) macosxGetGLProcAddress(func);
 #else
 
   // If the target system s UNIX and the ARB_get_proc_address
@@ -63,6 +70,9 @@ inline void (*SGLookupFunction(const char *func))() {
 
 
 /* OpenGL extension declarations */
+#define GL_POINT_SIZE_MIN_EXT                                   0x8126
+#define GL_DISTANCE_ATTENUATION_EXT                             0x8129
+
 typedef void (APIENTRY * glPointParameterfProc)(GLenum pname, GLfloat param);
 typedef void (APIENTRY * glPointParameterfvProc)(GLenum pname, const GLfloat *params);