add glad to load OpenGL extensions

src/main.cpp

@@ -707,6 +707,22 @@ BOOL UnadjustWindowRectEx(LPRECT prc, DWORD dwStyle, BOOL fMenu, DWORD dwExStyle
     return fRc;
 }
 
+void _pre_call_callback(const char* name, void* funcptr, int len_args, ...)
+{
+    assert(App::I.is_render_thread());
+}
+
+void _post_call_callback(const char* name, void* funcptr, int len_args, ...)
+{
+    GLenum error_code;
+    error_code = glad_glGetError();
+
+    if (error_code != GL_NO_ERROR)
+    {
+        LOG("ERROR %d in %s\n", error_code, name);
+    }
+}
+
 int main(int argc, char** argv)
 {
     WNDCLASS wc;
@@ -814,8 +830,16 @@ int main(int argc, char** argv)
     wglMakeCurrent(hDC, hRC);
 
     // Initialize extensions
-    if (glewInit() != GLEW_OK)
+    if (!gladLoadGL())
+    {
+        LOG("gladLoadGL() failed");
         return 0;
+    }
+    if (!gladLoadWGL(hDC))
+    {
+        LOG("gladLoadWGL() failed");
+        return 0;
+    }
 
     LOG("GL version: %s", glGetString(GL_VERSION));
     LOG("GL vendor: %s", glGetString(GL_VENDOR));
@@ -825,13 +849,13 @@ int main(int argc, char** argv)
     swprintf_s(window_title, L"PanoPainter %s (%s)", g_version_number_w, 
         str2wstr((char*)glGetString(GL_RENDERER)).c_str());
 
-    // If supported create a 3.1 context
-    if (wglewIsSupported("WGL_ARB_create_context"))
+    // If supported create a 3.3 context
+    if (GLAD_WGL_ARB_create_context)
     {
         int contex_attribs[] =
         {
             WGL_CONTEXT_MAJOR_VERSION_ARB, 3,
-            WGL_CONTEXT_MINOR_VERSION_ARB, 1,
+            WGL_CONTEXT_MINOR_VERSION_ARB, 3,
             WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
             WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB,
             0
@@ -904,6 +928,11 @@ int main(int argc, char** argv)
     App::I.render_thread_start();
     App::I.ui_thread_start();
 
+#ifdef _DEBUG
+    glad_set_pre_callback(_pre_call_callback);
+    glad_set_post_callback(_post_call_callback);
+#endif
+
     LOG("init app");
     App::I.init();