NewFrame(): using literal strings in the most-frequently firing IM_ASSERT expression to increase the odd of programmers seeing them (especially those who don't use a debugger).

imgui.cpp

@@ -2204,12 +2204,13 @@ void ImGui::NewFrame()
     ImGuiContext& g = *GImGui;
 
     // Check user data
-    IM_ASSERT(g.IO.DeltaTime >= 0.0f);               // Need a positive DeltaTime (zero is tolerated but will cause some timing issues)
-    IM_ASSERT(g.IO.DisplaySize.x >= 0.0f && g.IO.DisplaySize.y >= 0.0f);
-    IM_ASSERT(g.IO.Fonts->Fonts.Size > 0);           // Font Atlas not created. Did you call io.Fonts->GetTexDataAsRGBA32 / GetTexDataAsAlpha8 ?
-    IM_ASSERT(g.IO.Fonts->Fonts[0]->IsLoaded());     // Font Atlas not created. Did you call io.Fonts->GetTexDataAsRGBA32 / GetTexDataAsAlpha8 ?
-    IM_ASSERT(g.Style.CurveTessellationTol > 0.0f);  // Invalid style setting
-    IM_ASSERT(g.Style.Alpha >= 0.0f && g.Style.Alpha <= 1.0f);  // Invalid style setting. Alpha cannot be negative (allows us to avoid a few clamps in color computations)
+    // (We pass an error message in the assert expression as a trick to get it visible to programmers who are not using a debugger, as most assert handlers display their argument)
+    IM_ASSERT(g.IO.DeltaTime >= 0.0f                                    && "Need a positive DeltaTime (zero is tolerated but will cause some timing issues)");
+    IM_ASSERT(g.IO.DisplaySize.x >= 0.0f && g.IO.DisplaySize.y >= 0.0f  && "Invalid DisplaySize value");
+    IM_ASSERT(g.IO.Fonts->Fonts.Size > 0                                && "Font Atlas not created. Did you call io.Fonts->GetTexDataAsRGBA32 / GetTexDataAsAlpha8 ?");
+    IM_ASSERT(g.IO.Fonts->Fonts[0]->IsLoaded()                          && "Font Atlas not created. Did you call io.Fonts->GetTexDataAsRGBA32 / GetTexDataAsAlpha8 ?");
+    IM_ASSERT(g.Style.CurveTessellationTol > 0.0f                       && "Invalid style setting");
+    IM_ASSERT(g.Style.Alpha >= 0.0f && g.Style.Alpha <= 1.0f            && "Invalid style setting. Alpha cannot be negative (allows us to avoid a few clamps in color computations)");
 
     // Initialize on first frame
     if (!g.Initialized)