Viewports: trying to treat GetMainViewport() as const. Reducing unnecessary casts of ImGuiViewportP*

Metrics: readded root Drawlists node in metrics to match master.
The (void*) casts are implying const-casst but currently left GetMainViewport() as returning non-const.

imgui.cpp

@@ -5295,7 +5295,7 @@ ImGuiWindow* ImGui::FindWindowByName(const char* name)
 
 static void ApplyWindowSettings(ImGuiWindow* window, ImGuiWindowSettings* settings)
 {
-    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    const ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     window->ViewportPos = main_viewport->Pos;
     if (settings->ViewportId)
     {
@@ -5321,7 +5321,7 @@ static ImGuiWindow* CreateNewWindow(const char* name, ImGuiWindowFlags flags)
     g.WindowsById.SetVoidPtr(window->ID, window);
 
     // Default/arbitrary window position. Use SetNextWindowPos() with the appropriate condition flag to change the initial position of a window.
-    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    const ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     window->Pos = main_viewport->Pos + ImVec2(60, 60);
     window->ViewportPos = main_viewport->Pos;
 
@@ -6412,7 +6412,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
                 if (window->Viewport->PlatformMonitor == -1)
                 {
                     // Fallback for "lost" window (e.g. a monitor disconnected): we move the window back over the main viewport
-                    ImGuiViewport* main_viewport = GetMainViewport();
+                    const ImGuiViewport* main_viewport = GetMainViewport();
                     SetWindowPos(window, main_viewport->Pos + style.DisplayWindowPadding, ImGuiCond_Always);
                 }
                 else
@@ -8878,8 +8878,8 @@ bool ImGui::BeginPopupModal(const char* name, bool* p_open, ImGuiWindowFlags fla
     // FIXME: Should test for (PosCond & window->SetWindowPosAllowFlags) with the upcoming window.
     if ((g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasPos) == 0)
     {
-        ImGuiViewportP* viewport = window->WasActive ? window->Viewport : (ImGuiViewportP*)GetMainViewport(); // FIXME-VIEWPORT: What may be our reference viewport?
-        SetNextWindowPos(viewport->GetMainRect().GetCenter(), ImGuiCond_FirstUseEver, ImVec2(0.5f, 0.5f));
+        const ImGuiViewport* viewport = window->WasActive ? window->Viewport : GetMainViewport(); // FIXME-VIEWPORT: What may be our reference viewport?
+        SetNextWindowPos(viewport->GetCenter(), ImGuiCond_FirstUseEver, ImVec2(0.5f, 0.5f));
     }
 
     flags |= ImGuiWindowFlags_Popup | ImGuiWindowFlags_Modal | ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoDocking;
@@ -10259,7 +10259,7 @@ void ImGui::NavUpdateWindowingOverlay()
 
     if (g.NavWindowingListWindow == NULL)
         g.NavWindowingListWindow = FindWindowByName("###NavWindowingList");
-    ImGuiViewportP* viewport = /*g.NavWindow ? g.NavWindow->Viewport :*/ (ImGuiViewportP*)GetMainViewport();
+    const ImGuiViewport* viewport = /*g.NavWindow ? g.NavWindow->Viewport :*/ GetMainViewport();
     SetNextWindowSizeConstraints(ImVec2(viewport->Size.x * 0.20f, viewport->Size.y * 0.20f), ImVec2(FLT_MAX, FLT_MAX));
     SetNextWindowPos(viewport->Pos + viewport->Size * 0.5f, ImGuiCond_Always, ImVec2(0.5f, 0.5f));
     PushStyleVar(ImGuiStyleVar_WindowPadding, g.Style.WindowPadding * 2.0f);
@@ -11589,7 +11589,7 @@ static void ImGui::UpdateSelectWindowViewport(ImGuiWindow* window)
     window->ViewportAllowPlatformMonitorExtend = -1;
 
     // Restore main viewport if multi-viewport is not supported by the backend
-    ImGuiViewportP* main_viewport = (ImGuiViewportP*)GetMainViewport();
+    ImGuiViewportP* main_viewport = (ImGuiViewportP*)(void*)GetMainViewport();
     if (!(g.ConfigFlagsCurrFrame & ImGuiConfigFlags_ViewportsEnable))
     {
         SetWindowViewport(window, main_viewport);
@@ -14409,7 +14409,7 @@ void ImGui::DockNodeTreeUpdateSplitter(ImGuiDockNode* node)
 
                 /*
                 // [DEBUG] Render limits
-                ImDrawList* draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList((ImGuiViewportP*)GetMainViewport());
+                ImDrawList* draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList(GetMainViewport());
                 for (int n = 0; n < 2; n++)
                     if (axis == ImGuiAxis_X)
                         draw_list->AddLine(ImVec2(resize_limits[n], node->ChildNodes[n]->Pos.y), ImVec2(resize_limits[n], node->ChildNodes[n]->Pos.y + node->ChildNodes[n]->Size.y), IM_COL32(255, 0, 255, 255), 3.0f);
@@ -14437,7 +14437,7 @@ void ImGui::DockNodeTreeUpdateSplitter(ImGuiDockNode* node)
                         for (int touching_node_n = 0; touching_node_n < touching_nodes[side_n].Size; touching_node_n++)
                         {
                             ImGuiDockNode* touching_node = touching_nodes[side_n][touching_node_n];
-                            //ImDrawList* draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList((ImGuiViewportP*)GetMainViewport());
+                            //ImDrawList* draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList(GetMainViewport());
                             //draw_list->AddRect(touching_node->Pos, touching_node->Pos + touching_node->Size, IM_COL32(255, 128, 0, 255));
                             while (touching_node->ParentNode != node)
                             {
@@ -14653,7 +14653,7 @@ void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags fla
 // The limitation with this call is that your window won't have a menu bar.
 // Even though we could pass window flags, it would also require the user to be able to call BeginMenuBar() somehow meaning we can't Begin/End in a single function.
 // But you can also use BeginMainMenuBar(). If you really want a menu bar inside the same window as the one hosting the dockspace, you will need to copy this code somewhere and tweak it.
-ImGuiID ImGui::DockSpaceOverViewport(ImGuiViewport* viewport, ImGuiDockNodeFlags dockspace_flags, const ImGuiWindowClass* window_class)
+ImGuiID ImGui::DockSpaceOverViewport(const ImGuiViewport* viewport, ImGuiDockNodeFlags dockspace_flags, const ImGuiWindowClass* window_class)
 {
     if (viewport == NULL)
         viewport = GetMainViewport();
@@ -15980,9 +15980,33 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         TreePop();
     }
 
-    // Contents
+    // Windows
     DebugNodeWindowsList(&g.Windows, "Windows");
     //DebugNodeWindowsList(&g.WindowsFocusOrder, "WindowsFocusOrder");
+
+    // Drawlists
+    int drawlist_count = 0;
+    for (int viewport_i = 0; viewport_i < g.Viewports.Size; viewport_i++)
+        drawlist_count += g.Viewports[viewport_i]->DrawDataBuilder.GetDrawListCount();
+    if (TreeNode("DrawLists", "DrawLists (%d)", drawlist_count))
+    {
+        for (int viewport_i = 0; viewport_i < g.Viewports.Size; viewport_i++)
+        {
+            ImGuiViewportP* viewport = g.Viewports[viewport_i];
+            bool viewport_has_drawlist = false;
+            for (int layer_i = 0; layer_i < IM_ARRAYSIZE(viewport->DrawDataBuilder.Layers); layer_i++)
+                for (int draw_list_i = 0; draw_list_i < viewport->DrawDataBuilder.Layers[layer_i].Size; draw_list_i++)
+                {
+                    if (!viewport_has_drawlist)
+                        ImGui::Text("Active DrawLists in Viewport #%d, ID: 0x%08X", viewport->Idx, viewport->ID);
+                    viewport_has_drawlist = true;
+                    DebugNodeDrawList(NULL, viewport, viewport->DrawDataBuilder.Layers[layer_i][draw_list_i], "DrawList");
+                }
+        }
+        TreePop();
+    }
+
+    // Viewports
     if (TreeNode("Viewports", "Viewports (%d)", g.Viewports.Size))
     {
         Indent(GetTreeNodeToLabelSpacing());
@@ -16228,7 +16252,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         char buf[64] = "";
         char* p = buf;
         ImGuiDockNode* node = g.HoveredDockNode;
-        ImDrawList* overlay_draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList((ImGuiViewportP*)GetMainViewport());
+        ImDrawList* overlay_draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList(GetMainViewport());
         p += ImFormatString(p, buf + IM_ARRAYSIZE(buf) - p, "DockId: %X%s\n", node->ID, node->IsCentralNode() ? " *CentralNode*" : "");
         p += ImFormatString(p, buf + IM_ARRAYSIZE(buf) - p, "WindowClass: %08X\n", node->WindowClass.ClassId);
         p += ImFormatString(p, buf + IM_ARRAYSIZE(buf) - p, "Size: (%.0f, %.0f)\n", node->Size.x, node->Size.y);

imgui.h

@@ -756,7 +756,7 @@ namespace ImGui
     // - Use DockSpace() to create an explicit dock node _within_ an existing window. See Docking demo for details.
     // - DockSpace() needs to be submitted _before_ any window they can host. If you use a dockspace, submit it early in your app.
     IMGUI_API void          DockSpace(ImGuiID id, const ImVec2& size = ImVec2(0, 0), ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
-    IMGUI_API ImGuiID       DockSpaceOverViewport(ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
+    IMGUI_API ImGuiID       DockSpaceOverViewport(const ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
     IMGUI_API void          SetNextWindowDockID(ImGuiID dock_id, ImGuiCond cond = 0);           // set next window dock id (FIXME-DOCK)
     IMGUI_API void          SetNextWindowClass(const ImGuiWindowClass* window_class);           // set next window class (rare/advanced uses: provide hints to the platform backend via altered viewport flags and parent/child info)
     IMGUI_API ImGuiID       GetWindowDockID();
@@ -2874,9 +2874,9 @@ struct ImGuiViewport
     ~ImGuiViewport()    { IM_ASSERT(PlatformUserData == NULL && RendererUserData == NULL); }
 
     // Access work-area rectangle with GetWorkXXX functions (see comments above)
-    ImVec2              GetCenter()             { return ImVec2(Pos.x + Size.x * 0.5f, Pos.y + Size.y * 0.5f); }
-    ImVec2              GetWorkPos()            { return ImVec2(Pos.x + WorkOffsetMin.x, Pos.y + WorkOffsetMin.y); }
-    ImVec2              GetWorkSize()           { return ImVec2(Size.x - WorkOffsetMin.x + WorkOffsetMax.x, Size.y - WorkOffsetMin.y + WorkOffsetMax.y); } // This not clamped
+    ImVec2              GetCenter() const       { return ImVec2(Pos.x + Size.x * 0.5f, Pos.y + Size.y * 0.5f); }
+    ImVec2              GetWorkPos() const      { return ImVec2(Pos.x + WorkOffsetMin.x, Pos.y + WorkOffsetMin.y); }
+    ImVec2              GetWorkSize() const     { return ImVec2(Size.x - WorkOffsetMin.x + WorkOffsetMax.x, Size.y - WorkOffsetMin.y + WorkOffsetMax.y); } // This not clamped
 };
 
 //-----------------------------------------------------------------------------

imgui_demo.cpp

@@ -333,7 +333,7 @@ void ImGui::ShowDemoWindow(bool* p_open)
 
     // We specify a default position/size in case there's no data in the .ini file.
     // We only do it to make the demo applications a little more welcoming, but typically this isn't required.
-    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    const ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     ImGui::SetNextWindowPos(ImVec2(main_viewport->GetWorkPos().x + 650, main_viewport->GetWorkPos().y + 20), ImGuiCond_FirstUseEver);
     ImGui::SetNextWindowSize(ImVec2(550, 680), ImGuiCond_FirstUseEver);
 
@@ -7031,7 +7031,7 @@ static void ShowExampleAppSimpleOverlay(bool* p_open)
     if (corner != -1)
     {
         window_flags |= ImGuiWindowFlags_NoMove;
-        ImGuiViewport* viewport = ImGui::GetMainViewport();
+        const ImGuiViewport* viewport = ImGui::GetMainViewport();
         ImVec2 work_area_pos = viewport->GetWorkPos();   // Instead of using viewport->Pos we use GetWorkPos() to avoid menu bars, if any!
         ImVec2 work_area_size = viewport->GetWorkSize();
         ImVec2 window_pos = ImVec2((corner & 1) ? (work_area_pos.x + work_area_size.x - DISTANCE) : (work_area_pos.x + DISTANCE), (corner & 2) ? (work_area_pos.y + work_area_size.y - DISTANCE) : (work_area_pos.y + DISTANCE));
@@ -7368,7 +7368,7 @@ void ShowExampleAppDockSpace(bool* p_open)
     ImGuiWindowFlags window_flags = ImGuiWindowFlags_MenuBar | ImGuiWindowFlags_NoDocking;
     if (opt_fullscreen)
     {
-        ImGuiViewport* viewport = ImGui::GetMainViewport();
+        const ImGuiViewport* viewport = ImGui::GetMainViewport();
         ImGui::SetNextWindowPos(viewport->GetWorkPos());
         ImGui::SetNextWindowSize(viewport->GetWorkSize());
         ImGui::SetNextWindowViewport(viewport->ID);

imgui_internal.h

@@ -664,8 +664,9 @@ struct ImDrawDataBuilder
 {
     ImVector<ImDrawList*>   Layers[2];           // Global layers for: regular, tooltip
 
-    void Clear()            { for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n].resize(0); }
-    void ClearFreeMemory()  { for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n].clear(); }
+    void Clear()                    { for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n].resize(0); }
+    void ClearFreeMemory()          { for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n].clear(); }
+    int  GetDrawListCount() const   { int count = 0; for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) count += Layers[n].Size; return count; }
     IMGUI_API void FlattenIntoSingleLayer();
 };
 

imgui_widgets.cpp

@@ -6575,7 +6575,7 @@ void ImGui::EndMenuBar()
 bool ImGui::BeginMainMenuBar()
 {
     ImGuiContext& g = *GImGui;
-    ImGuiViewportP* viewport = (ImGuiViewportP*)GetMainViewport();
+    ImGuiViewportP* viewport = (ImGuiViewportP*)(void*)GetMainViewport();
     ImGuiWindow* menu_bar_window = FindWindowByName("##MainMenuBar");
 
     // For the main menu bar, which cannot be moved, we honor g.Style.DisplaySafeAreaPadding to ensure text can be visible on a TV set.