ImDrawData: changed CmdLists from raw array to ImVector<> owned by Im…

…DrawData itself. Faclitate user-manipulation of the array (#6406, #4879, #1878) + deep swap. (#6597, #6475, #6167, #5776, #5109, #4763, #3515, #1860) + Metrics: avoid misleadingly iterating all layers of DrawDataBuilder as everything is flattened into Layers[0] at this point. # Conflicts: # imgui.cpp # imgui_internal.h
ocornut · Jul 12, 2023 · c649aca · c649aca
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diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
@@ -39,9 +39,20 @@ Breaking changes:
 - IO: Obsoleted io.ClearInputCharacters() (added in 1.47) as it now ambiguous
   and often incorrect/misleading considering the existence of a higher-level
   input queue. (#4921)
+- ImDrawData: CmdLists[] arra is now owned, changed from 'ImDrawList**' to
+  'ImVector<ImDrawList*>'. Majority of users shouldn't be affected, but you
+  cannot compare to NULL nor reassign manually anymore.
+  Instead use AddDrawList(). (#6406, #4879, #1878)
 
 Other changes:
 
+- ImDrawData: CmdLists[] array is now an ImVector<> owned by ImDrawData rather
+  than a pointer to internal state.
+  - This makes it easier for user to create their own or append to an existing draw data.
+    (#6406, #4879, #1878)
+  - This makes it easier to perform a deep-swap instead of a deep-copy, as array
+    ownership is now clear. (#6597, #6475, #6167, #5776, #5109, #4763, #3515, #1860)
+  - Syntax and allocation count are otherwise identical.
 - Fixed CTRL+Tab dimming background assert when target window has a callback
   in the last ImDrawCmd. (#4857, #5937)
 - InputText: Fixed a case where deactivation frame would write to underlying

diff --git a/imgui.cpp b/imgui.cpp
@@ -399,6 +399,7 @@ CODE
  When you are not sure about an old symbol or function name, try using the Search/Find function of your IDE to look for comments or references in all imgui files.
  You can read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2023/07/12 (1.89.8) - ImDrawData: CmdLists now owned, changed from ImDrawList** to ImVector<ImDrawList*>. Majority of users shouldn't be affected, but you cannot compare to NULL nor reassign manually anymore. Instead use AddDrawList(). (#6406, #4879, #1878)
  - 2023/06/28 (1.89.7) - overlapping items: obsoleted 'SetItemAllowOverlap()' (called after item) in favor of calling 'SetNextItemAllowOverlap()' (called before item). 'SetItemAllowOverlap()' didn't and couldn't work reliably since 1.89 (2022-11-15).
  - 2023/06/28 (1.89.7) - overlapping items: renamed 'ImGuiTreeNodeFlags_AllowItemOverlap' to 'ImGuiTreeNodeFlags_AllowOverlap', 'ImGuiSelectableFlags_AllowItemOverlap' to 'ImGuiSelectableFlags_AllowOverlap'. Kept redirecting enums (will obsolete).
  - 2023/06/28 (1.89.7) - overlapping items: IsItemHovered() now by default return false when querying an item using AllowOverlap mode which is being overlapped. Use ImGuiHoveredFlags_AllowWhenOverlappedByItem to revert to old behavior.
@@ -4823,7 +4824,7 @@ static void AddWindowToDrawData(ImGuiWindow* window, int layer)
     ImGuiContext& g = *GImGui;
     ImGuiViewportP* viewport = g.Viewports[0];
     g.IO.MetricsRenderWindows++;
-    AddDrawListToDrawData(&viewport->DrawDataBuilder.Layers[layer], window->DrawList);
+    AddDrawListToDrawData(viewport->DrawDataBuilder.Layers[layer], window->DrawList);
     for (int i = 0; i < window->DC.ChildWindows.Size; i++)
     {
         ImGuiWindow* child = window->DC.ChildWindows[i];
@@ -4845,36 +4846,36 @@ static inline void AddRootWindowToDrawData(ImGuiWindow* window)
 
 void ImDrawDataBuilder::FlattenIntoSingleLayer()
 {
-    int n = Layers[0].Size;
-    int size = n;
+    int n = Layers[0]->Size;
+    int full_size = n;
     for (int i = 1; i < IM_ARRAYSIZE(Layers); i++)
-        size += Layers[i].Size;
-    Layers[0].resize(size);
+        full_size += Layers[i]->Size;
+    Layers[0]->resize(full_size);
     for (int layer_n = 1; layer_n < IM_ARRAYSIZE(Layers); layer_n++)
     {
-        ImVector<ImDrawList*>& layer = Layers[layer_n];
-        if (layer.empty())
+        ImVector<ImDrawList*>* layer = Layers[layer_n];
+        if (layer->empty())
             continue;
-        memcpy(&Layers[0][n], &layer[0], layer.Size * sizeof(ImDrawList*));
-        n += layer.Size;
-        layer.resize(0);
+        memcpy(Layers[0]->Data + n, layer->Data, layer->Size * sizeof(ImDrawList*));
+        n += layer->Size;
+        layer->resize(0);
     }
 }
 
-static void SetupViewportDrawData(ImGuiViewportP* viewport, ImVector<ImDrawList*>* draw_lists)
+static void SetupViewportDrawData(ImGuiViewportP* viewport)
 {
     ImGuiIO& io = ImGui::GetIO();
     ImDrawData* draw_data = &viewport->DrawDataP;
     draw_data->Valid = true;
-    draw_data->CmdLists = (draw_lists->Size > 0) ? draw_lists->Data : NULL;
-    draw_data->CmdListsCount = draw_lists->Size;
+    draw_data->CmdListsCount = draw_data->CmdLists.Size;
     draw_data->TotalVtxCount = draw_data->TotalIdxCount = 0;
     draw_data->DisplayPos = viewport->Pos;
     draw_data->DisplaySize = viewport->Size;
     draw_data->FramebufferScale = io.DisplayFramebufferScale;
-    for (int n = 0; n < draw_lists->Size; n++)
+    draw_data->OwnerViewport = viewport;
+    for (int n = 0; n < draw_data->CmdLists.Size; n++)
     {
-        ImDrawList* draw_list = draw_lists->Data[n];
+        ImDrawList* draw_list = draw_data->CmdLists[n];
         draw_list->_PopUnusedDrawCmd();
         draw_data->TotalVtxCount += draw_list->VtxBuffer.Size;
         draw_data->TotalIdxCount += draw_list->IdxBuffer.Size;
@@ -5099,9 +5100,9 @@ void ImGui::Render()
     for (int n = 0; n != g.Viewports.Size; n++)
     {
         ImGuiViewportP* viewport = g.Viewports[n];
-        viewport->DrawDataBuilder.Clear();
+        viewport->DrawDataBuilder.Setup(&viewport->DrawDataP);
         if (viewport->DrawLists[0] != NULL)
-            AddDrawListToDrawData(&viewport->DrawDataBuilder.Layers[0], GetBackgroundDrawList(viewport));
+            AddDrawListToDrawData(viewport->DrawDataBuilder.Layers[0], GetBackgroundDrawList(viewport));
     }
 
     // Draw modal/window whitening backgrounds
@@ -5136,9 +5137,9 @@ void ImGui::Render()
 
         // Add foreground ImDrawList (for each active viewport)
         if (viewport->DrawLists[1] != NULL)
-            AddDrawListToDrawData(&viewport->DrawDataBuilder.Layers[0], GetForegroundDrawList(viewport));
+            AddDrawListToDrawData(viewport->DrawDataBuilder.Layers[0], GetForegroundDrawList(viewport));
 
-        SetupViewportDrawData(viewport, &viewport->DrawDataBuilder.Layers[0]);
+        SetupViewportDrawData(viewport);
         ImDrawData* draw_data = &viewport->DrawDataP;
         g.IO.MetricsRenderVertices += draw_data->TotalVtxCount;
         g.IO.MetricsRenderIndices += draw_data->TotalIdxCount;
@@ -13862,17 +13863,16 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     // 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();
+        drawlist_count += g.Viewports[viewport_i]->DrawDataP.CmdLists.Size;
     if (TreeNode("DrawLists", "DrawLists (%d)", drawlist_count))
     {
         Checkbox("Show ImDrawCmd mesh when hovering", &cfg->ShowDrawCmdMesh);
         Checkbox("Show ImDrawCmd bounding boxes when hovering", &cfg->ShowDrawCmdBoundingBoxes);
         for (int viewport_i = 0; viewport_i < g.Viewports.Size; viewport_i++)
         {
             ImGuiViewportP* viewport = g.Viewports[viewport_i];
-            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++)
-                    DebugNodeDrawList(NULL, viewport->DrawDataBuilder.Layers[layer_i][draw_list_i], "DrawList");
+            for (int draw_list_i = 0; draw_list_i < viewport->DrawDataP.CmdLists.Size; draw_list_i++)
+                DebugNodeDrawList(NULL, viewport, viewport->DrawDataP.CmdLists[draw_list_i], "DrawList");
         }
         TreePop();
     }
@@ -14204,9 +14204,10 @@ void ImGui::DebugNodeColumns(ImGuiOldColumns* columns)
 }
 
 // [DEBUG] Display contents of ImDrawList
-void ImGui::DebugNodeDrawList(ImGuiWindow* window, const ImDrawList* draw_list, const char* label)
+void ImGui::DebugNodeDrawList(ImGuiWindow* window, ImGuiViewportP* viewport, const ImDrawList* draw_list, const char* label)
 {
     ImGuiContext& g = *GImGui;
+    IM_UNUSED(viewport); // Used in docking branch
     ImGuiMetricsConfig* cfg = &g.DebugMetricsConfig;
     int cmd_count = draw_list->CmdBuffer.Size;
     if (cmd_count > 0 && draw_list->CmdBuffer.back().ElemCount == 0 && draw_list->CmdBuffer.back().UserCallback == NULL)
@@ -14495,9 +14496,8 @@ void ImGui::DebugNodeViewport(ImGuiViewportP* viewport)
             (flags & ImGuiViewportFlags_IsPlatformWindow)  ? " IsPlatformWindow"  : "",
             (flags & ImGuiViewportFlags_IsPlatformMonitor) ? " IsPlatformMonitor" : "",
             (flags & ImGuiViewportFlags_OwnedByApp)        ? " OwnedByApp"        : "");
-        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++)
-                DebugNodeDrawList(NULL, viewport->DrawDataBuilder.Layers[layer_i][draw_list_i], "DrawList");
+        for (int draw_list_i = 0; draw_list_i < viewport->DrawDataP.CmdLists.Size; draw_list_i++)
+            DebugNodeDrawList(NULL, viewport, viewport->DrawDataP.CmdLists[draw_list_i], "DrawList");
         TreePop();
     }
 }
@@ -14525,7 +14525,7 @@ void ImGui::DebugNodeWindow(ImGuiWindow* window, const char* label)
         TextDisabled("Note: some memory buffers have been compacted/freed.");
 
     ImGuiWindowFlags flags = window->Flags;
-    DebugNodeDrawList(window, window->DrawList, "DrawList");
+    DebugNodeDrawList(window, window->Viewport, window->DrawList, "DrawList");
     BulletText("Pos: (%.1f,%.1f), Size: (%.1f,%.1f), ContentSize (%.1f,%.1f) Ideal (%.1f,%.1f)", window->Pos.x, window->Pos.y, window->Size.x, window->Size.y, window->ContentSize.x, window->ContentSize.y, window->ContentSizeIdeal.x, window->ContentSizeIdeal.y);
     BulletText("Flags: 0x%08X (%s%s%s%s%s%s%s%s%s..)", flags,
         (flags & ImGuiWindowFlags_ChildWindow)  ? "Child " : "",      (flags & ImGuiWindowFlags_Tooltip)     ? "Tooltip "   : "",  (flags & ImGuiWindowFlags_Popup) ? "Popup " : "",

diff --git a/imgui.h b/imgui.h
@@ -25,7 +25,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM >= 12345')
 #define IMGUI_VERSION       "1.89.8 WIP"
-#define IMGUI_VERSION_NUM   18972
+#define IMGUI_VERSION_NUM   18973
 #define IMGUI_HAS_TABLE
 
 /*
@@ -2743,18 +2743,19 @@ struct ImDrawList
 // as this is one of the oldest structure exposed by the library! Basically, ImDrawList == CmdList)
 struct ImDrawData
 {
-    bool            Valid;                  // Only valid after Render() is called and before the next NewFrame() is called.
-    int             CmdListsCount;          // Number of ImDrawList* to render
-    int             TotalIdxCount;          // For convenience, sum of all ImDrawList's IdxBuffer.Size
-    int             TotalVtxCount;          // For convenience, sum of all ImDrawList's VtxBuffer.Size
-    ImDrawList**    CmdLists;               // Array of ImDrawList* to render. The ImDrawList are owned by ImGuiContext and only pointed to from here.
-    ImVec2          DisplayPos;             // Top-left position of the viewport to render (== top-left of the orthogonal projection matrix to use) (== GetMainViewport()->Pos for the main viewport, == (0.0) in most single-viewport applications)
-    ImVec2          DisplaySize;            // Size of the viewport to render (== GetMainViewport()->Size for the main viewport, == io.DisplaySize in most single-viewport applications)
-    ImVec2          FramebufferScale;       // Amount of pixels for each unit of DisplaySize. Based on io.DisplayFramebufferScale. Generally (1,1) on normal display, (2,2) on OSX with Retina display.
+    bool                Valid;              // Only valid after Render() is called and before the next NewFrame() is called.
+    int                 CmdListsCount;      // Number of ImDrawList* to render (should always be == CmdLists.size)
+    int                 TotalIdxCount;      // For convenience, sum of all ImDrawList's IdxBuffer.Size
+    int                 TotalVtxCount;      // For convenience, sum of all ImDrawList's VtxBuffer.Size
+    ImVector<ImDrawList*> CmdLists;         // Array of ImDrawList* to render. The ImDrawLists are owned by ImGuiContext and only pointed to from here.
+    ImVec2              DisplayPos;         // Top-left position of the viewport to render (== top-left of the orthogonal projection matrix to use) (== GetMainViewport()->Pos for the main viewport, == (0.0) in most single-viewport applications)
+    ImVec2              DisplaySize;        // Size of the viewport to render (== GetMainViewport()->Size for the main viewport, == io.DisplaySize in most single-viewport applications)
+    ImVec2              FramebufferScale;   // Amount of pixels for each unit of DisplaySize. Based on io.DisplayFramebufferScale. Generally (1,1) on normal display, (2,2) on OSX with Retina display.
+    ImGuiViewport*      OwnerViewport;      // Viewport carrying the ImDrawData instance, might be of use to the renderer (generally not).
 
     // Functions
     ImDrawData()    { Clear(); }
-    void Clear()    { memset(this, 0, sizeof(*this)); }     // The ImDrawList are owned by ImGuiContext!
+    IMGUI_API void  Clear();
     IMGUI_API void  DeIndexAllBuffers();                    // Helper to convert all buffers from indexed to non-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
     IMGUI_API void  ScaleClipRects(const ImVec2& fb_scale); // Helper to scale the ClipRect field of each ImDrawCmd. Use if your final output buffer is at a different scale than Dear ImGui expects, or if there is a difference between your window resolution and framebuffer resolution.
 };

diff --git a/imgui_draw.cpp b/imgui_draw.cpp
@@ -1808,6 +1808,15 @@ void ImDrawListSplitter::SetCurrentChannel(ImDrawList* draw_list, int idx)
 // [SECTION] ImDrawData
 //-----------------------------------------------------------------------------
 
+void ImDrawData::Clear()
+{
+    Valid = false;
+    CmdListsCount = TotalIdxCount = TotalVtxCount = 0;
+    CmdLists.resize(0); // The ImDrawList are NOT owned by ImDrawData but e.g. by ImGuiContext, so we don't clear them.
+    DisplayPos = DisplaySize = FramebufferScale = ImVec2(0.0f, 0.0f);
+    OwnerViewport = NULL;
+}
+
 // For backward compatibility: convert all buffers from indexed to de-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
 void ImDrawData::DeIndexAllBuffers()
 {

diff --git a/imgui_internal.h b/imgui_internal.h
@@ -772,11 +772,11 @@ struct IMGUI_API ImDrawListSharedData
 
 struct ImDrawDataBuilder
 {
-    ImVector<ImDrawList*>   Layers[2];           // Global layers for: regular, tooltip
+    ImVector<ImDrawList*>*  Layers[2];      // Pointers to global layers for: regular, tooltip. LayersP[0] is owned by DrawData.
+    ImVector<ImDrawList*>   LayerData1;
 
-    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; }
+    ImDrawDataBuilder()                     { memset(this, 0, sizeof(*this)); }
+    void Setup(ImDrawData* draw_data)       { Layers[0] = &draw_data->CmdLists; Layers[1] = &LayerData1; for (int n = 0; n < IM_ARRAYSIZE(Layers); n++) Layers[n]->resize(0); }
     IMGUI_API void FlattenIntoSingleLayer();
 };
 
@@ -1605,8 +1605,7 @@ struct ImGuiViewportP : public ImGuiViewport
     int                 DrawListsLastFrame[2];  // Last frame number the background (0) and foreground (1) draw lists were used
     ImDrawList*         DrawLists[2];           // Convenience background (0) and foreground (1) draw lists. We use them to draw software mouser cursor when io.MouseDrawCursor is set and to draw most debug overlays.
     ImDrawData          DrawDataP;
-    ImDrawDataBuilder   DrawDataBuilder;
-
+    ImDrawDataBuilder   DrawDataBuilder;        // Temporary data while building final ImDrawData
     ImVec2              WorkOffsetMin;          // Work Area: Offset from Pos to top-left corner of Work Area. Generally (0,0) or (0,+main_menu_bar_height). Work Area is Full Area but without menu-bars/status-bars (so WorkArea always fit inside Pos/Size!)
     ImVec2              WorkOffsetMax;          // Work Area: Offset from Pos+Size to bottom-right corner of Work Area. Generally (0,0) or (0,-status_bar_height).
     ImVec2              BuildWorkOffsetMin;     // Work Area: Offset being built during current frame. Generally >= 0.0f.
@@ -3240,7 +3239,7 @@ namespace ImGui
     IMGUI_API void          ShowFontAtlas(ImFontAtlas* atlas);
     IMGUI_API void          DebugHookIdInfo(ImGuiID id, ImGuiDataType data_type, const void* data_id, const void* data_id_end);
     IMGUI_API void          DebugNodeColumns(ImGuiOldColumns* columns);
-    IMGUI_API void          DebugNodeDrawList(ImGuiWindow* window, const ImDrawList* draw_list, const char* label);
+    IMGUI_API void          DebugNodeDrawList(ImGuiWindow* window, ImGuiViewportP* viewport, const ImDrawList* draw_list, const char* label);
     IMGUI_API void          DebugNodeDrawCmdShowMeshAndBoundingBox(ImDrawList* out_draw_list, const ImDrawList* draw_list, const ImDrawCmd* draw_cmd, bool show_mesh, bool show_aabb);
     IMGUI_API void          DebugNodeFont(ImFont* font);
     IMGUI_API void          DebugNodeFontGlyph(ImFont* font, const ImFontGlyph* glyph);