Updated ImGui.

3rdparty/dear-imgui/imgui.cpp

@@ -3557,7 +3557,10 @@ void ImGui::EndFrame()
     IM_ASSERT(g.Initialized);
     if (g.FrameCountEnded == g.FrameCount)          // Don't process EndFrame() multiple times.
         return;
-    IM_ASSERT(g.FrameScopeActive && "Forgot to call ImGui::NewFrame()");
+    IM_ASSERT(g.FrameScopeActive && "Forgot to call ImGui::NewFrame()?");
+
+    g.FrameScopeActive = false;
+    g.FrameCountEnded = g.FrameCount;
 
     // Notify OS when our Input Method Editor cursor has moved (e.g. CJK inputs using Microsoft IME)
     if (g.IO.ImeSetInputScreenPosFn && ImLengthSqr(g.PlatformImeLastPos - g.PlatformImePos) > 0.0001f)
@@ -3566,8 +3569,23 @@ void ImGui::EndFrame()
         g.PlatformImeLastPos = g.PlatformImePos;
     }
 
-    // Hide implicit "Debug" window if it hasn't been used
-    IM_ASSERT(g.CurrentWindowStack.Size == 1);    // Mismatched Begin()/End() calls, did you forget to call end on g.CurrentWindow->Name?
+    // Report when there is a mismatch of Begin/BeginChild vs End/EndChild calls. Important: Remember that the Begin/BeginChild API requires you
+    // to always call End/EndChild even if Begin/BeginChild returns false! (this is unfortunately inconsistent with most other Begin* API).
+    if (g.CurrentWindowStack.Size != 1)
+    {
+        if (g.CurrentWindowStack.Size > 1)
+        {
+            IM_ASSERT(g.CurrentWindowStack.Size == 1 && "Mismatched Begin/BeginChild vs End/EndChild calls: did you forget to call End/EndChild?");
+            while (g.CurrentWindowStack.Size > 1) // FIXME-ERRORHANDLING
+                End();
+        }
+        else
+        {
+            IM_ASSERT(g.CurrentWindowStack.Size == 1 && "Mismatched Begin/BeginChild vs End/EndChild calls: did you call End/EndChild too much?");
+        }
+    }
+
+    // Hide implicit/fallback "Debug" window if it hasn't been used
     if (g.CurrentWindow && !g.CurrentWindow->WriteAccessed)
         g.CurrentWindow->Active = false;
     End();
@@ -3660,9 +3678,6 @@ void ImGui::EndFrame()
     g.IO.MouseWheel = g.IO.MouseWheelH = 0.0f;
     memset(g.IO.InputCharacters, 0, sizeof(g.IO.InputCharacters));
     memset(g.IO.NavInputs, 0, sizeof(g.IO.NavInputs));
-
-    g.FrameScopeActive = false;
-    g.FrameCountEnded = g.FrameCount;
 }
 
 void ImGui::Render()
@@ -3703,7 +3718,7 @@ void ImGui::Render()
     g.IO.MetricsRenderVertices = g.DrawData.TotalVtxCount;
     g.IO.MetricsRenderIndices = g.DrawData.TotalIdxCount;
 
-    // Render. If user hasn't set a callback then they may retrieve the draw data via GetDrawData()
+    // (Legacy) Call the Render callback function. The current prefer way is to let the user retrieve GetDrawData() and call the render function themselves.
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     if (g.DrawData.CmdListsCount > 0 && g.IO.RenderDrawListsFn != NULL)
         g.IO.RenderDrawListsFn(&g.DrawData);
@@ -5246,6 +5261,13 @@ bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_first_use,
 void ImGui::End()
 {
     ImGuiContext& g = *GImGui;
+
+    if (g.CurrentWindowStack.Size <= 1 && g.FrameScopeActive)
+    {
+        IM_ASSERT(g.CurrentWindowStack.Size > 1 && "Calling End() too many times!");
+        return; // FIXME-ERRORHANDLING
+    }
+
     ImGuiWindow* window = g.CurrentWindow;
 
     if (window->DC.ColumnsSet != NULL)