added glad generator and a glad runtime

tools/glad-0.1.14a0/glad/lang/volt/loader/__init__.py

@@ -0,0 +1,64 @@
+
+LOAD_OPENGL_DLL = '''
+private global Library libGL;
+extern(System) private alias gladGetProcAddressPtrType = void* function(const(char)*);
+private global gladGetProcAddressPtrType gladGetProcAddressPtr;
+
+%(pre)s
+bool %(init)s() {
+    version(Windows) {
+        libGL = Library.load("opengl32.dll");
+    } else version(OSX) {
+        libGL = Library.loads([
+            "../Frameworks/OpenGL.framework/OpenGL",
+            "/Library/Frameworks/OpenGL.framework/OpenGL",
+            "/System/Library/Frameworks/OpenGL.framework/OpenGL",
+            "/System/Library/Frameworks/OpenGL.framework/Versions/Current/OpenGL"
+        ]);
+    } else {
+        libGL = Library.loads(["libGL.so.1", "libGL.so"]);
+    }
+
+    if(libGL !is null) {
+        version(Windows) {
+            string sym = "wglGetProcAddress";
+        } else {
+            string sym = "glXGetProcAddressARB";
+        }
+        // returns null on OSX, but that's fine
+        gladGetProcAddressPtr = cast(typeof(gladGetProcAddressPtr))libGL.symbol(sym);
+        return true;
+    }
+
+    return false;
+}
+
+private struct StructToDg {
+    void* instance;
+    void* func;
+}
+
+%(pre)s
+void* %(proc)s(string name) {
+    if(libGL is null) return null;
+    void* result;
+
+    if(gladGetProcAddressPtr !is null) {
+        // TODO: name.ptr
+        result = gladGetProcAddressPtr(name.ptr);
+    }
+    if(result is null) {
+        result = libGL.symbol(name);
+    }
+
+    return result;
+}
+
+%(pre)s
+void %(terminate)s() {
+    if(libGL !is null) {
+        libGL.free();
+    }
+    return;
+}
+'''