Reduced padding + unused storage in ImDrawList (224->192 bytes) + zero-init ImDrawListSplitter and ImDrawList

+ Readme tweak

docs/README.md

@@ -196,7 +196,7 @@ Ongoing Dear ImGui development is financially supported by users and private spo
 - [Blizzard](https://careers.blizzard.com/en-us/openings/engineering/all/all/all/1), [Google](https://github.com/google/filament), [Nvidia](https://developer.nvidia.com/nvidia-omniverse), [Ubisoft](https://montreal.ubisoft.com/en/ubisoft-sponsors-user-interface-library-for-c-dear-imgui/)
 
 *Double-chocolate and Salty caramel sponsors*
-- [Activision](https://careers.activision.com/c/programmingsoftware-engineering-jobs), [Arkane Studios](https://www.arkane-studios.com), [Dotemu](http://www.dotemu.com), [Framefield](http://framefield.com), [Hexagon](https://hexagonxalt.com/the-technology/xalt-visualization), [Kylotonn](https://www.kylotonn.com), [Media Molecule](http://www.mediamolecule.com), [Mesh Consultants](https://www.meshconsultants.ca), [Mobigame](http://www.mobigame.net), [Nadeo](https://www.nadeo.com), [Next Level Games](https://www.nextlevelgames.com), [RAD Game Tools](http://www.radgametools.com/), [Supercell](http://www.supercell.com), [Remedy Entertainment](https://www.remedygames.com/), [Unit 2 Games](https://unit2games.com/)
+- [Activision](https://careers.activision.com/c/programmingsoftware-engineering-jobs), [Arkane Studios](https://www.arkane-studios.com), [Dotemu](http://www.dotemu.com), [Framefield](http://framefield.com), [Grinding Gear Games](https://www.grindinggear.com), [Hexagon](https://hexagonxalt.com/the-technology/xalt-visualization), [Kylotonn](https://www.kylotonn.com), [Media Molecule](http://www.mediamolecule.com), [Mesh Consultants](https://www.meshconsultants.ca), [Mobigame](http://www.mobigame.net), [Nadeo](https://www.nadeo.com), [Next Level Games](https://www.nextlevelgames.com), [RAD Game Tools](http://www.radgametools.com/), [Supercell](http://www.supercell.com), [Remedy Entertainment](https://www.remedygames.com/), [Unit 2 Games](https://unit2games.com/)
 
 From November 2014 to December 2019, ongoing development has also been financially supported by its users on Patreon and through individual donations. Please see [detailed list of Dear ImGui supporters](https://github.com/ocornut/imgui/wiki/Sponsors).
 

imgui.h

@@ -2006,7 +2006,15 @@ struct ImDrawVert
 IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT;
 #endif
 
-// For use by ImDrawListSplitter.
+// [Internal] For use by ImDrawList
+struct ImDrawCmdHeader
+{
+    ImVec4          ClipRect;
+    ImTextureID     TextureId;
+    unsigned int    VtxOffset;
+};
+
+// [Internal] For use by ImDrawListSplitter
 struct ImDrawChannel
 {
     ImVector<ImDrawCmd>         _CmdBuffer;
@@ -2021,7 +2029,7 @@ struct ImDrawListSplitter
     int                         _Count;      // Number of active channels (1+)
     ImVector<ImDrawChannel>     _Channels;   // Draw channels (not resized down so _Count might be < Channels.Size)
 
-    inline ImDrawListSplitter()  { Clear(); }
+    inline ImDrawListSplitter()  { memset(this, 0, sizeof(*this)); }
     inline ~ImDrawListSplitter() { ClearFreeMemory(); }
     inline void                 Clear() { _Current = 0; _Count = 1; } // Do not clear Channels[] so our allocations are reused next frame
     IMGUI_API void              ClearFreeMemory();
@@ -2072,19 +2080,19 @@ struct ImDrawList
     ImDrawListFlags         Flags;              // Flags, you may poke into these to adjust anti-aliasing settings per-primitive.
 
     // [Internal, used while building lists]
+    unsigned int            _VtxCurrentIdx;     // [Internal] generally == VtxBuffer.Size unless we are past 64K vertices, in which case this gets reset to 0.
     const ImDrawListSharedData* _Data;          // Pointer to shared draw data (you can use ImGui::GetDrawListSharedData() to get the one from current ImGui context)
     const char*             _OwnerName;         // Pointer to owner window's name for debugging
-    unsigned int            _VtxCurrentIdx;     // [Internal] Generally == VtxBuffer.Size unless we are past 64K vertices, in which case this gets reset to 0.
     ImDrawVert*             _VtxWritePtr;       // [Internal] point within VtxBuffer.Data after each add command (to avoid using the ImVector<> operators too much)
     ImDrawIdx*              _IdxWritePtr;       // [Internal] point within IdxBuffer.Data after each add command (to avoid using the ImVector<> operators too much)
     ImVector<ImVec4>        _ClipRectStack;     // [Internal]
     ImVector<ImTextureID>   _TextureIdStack;    // [Internal]
     ImVector<ImVec2>        _Path;              // [Internal] current path building
-    ImDrawCmd               _CmdHeader;         // [Internal] Template of active commands. Fields should match those of CmdBuffer.back().
+    ImDrawCmdHeader         _CmdHeader;         // [Internal] template of active commands. Fields should match those of CmdBuffer.back().
     ImDrawListSplitter      _Splitter;          // [Internal] for channels api (note: prefer using your own persistent instance of ImDrawListSplitter!)
 
     // If you want to create ImDrawList instances, pass them ImGui::GetDrawListSharedData() or create and use your own ImDrawListSharedData (so you can use ImDrawList without ImGui)
-    ImDrawList(const ImDrawListSharedData* shared_data) { _Data = shared_data; Flags = ImDrawListFlags_None; _VtxCurrentIdx = 0; _VtxWritePtr = NULL; _IdxWritePtr = NULL; _OwnerName = NULL; }
+    ImDrawList(const ImDrawListSharedData* shared_data) { memset(this, 0, sizeof(*this)); _Data = shared_data; }
 
     ~ImDrawList() { _ClearFreeMemory(); }
     IMGUI_API void  PushClipRect(ImVec2 clip_rect_min, ImVec2 clip_rect_max, bool intersect_with_current_clip_rect = false);  // Render-level scissoring. This is passed down to your render function but not used for CPU-side coarse clipping. Prefer using higher-level ImGui::PushClipRect() to affect logic (hit-testing and widget culling)

imgui_internal.h

@@ -1692,9 +1692,9 @@ struct IMGUI_API ImGuiWindow
     ImGuiID                 NavLastIds[ImGuiNavLayer_COUNT];    // Last known NavId for this window, per layer (0/1)
     ImRect                  NavRectRel[ImGuiNavLayer_COUNT];    // Reference rectangle, in window relative space
 
-    bool                    MemoryCompacted;                    // Set when window extraneous data have been garbage collected
     int                     MemoryDrawListIdxCapacity;          // Backup of last idx/vtx count, so when waking up the window we can preallocate and avoid iterative alloc/copy
     int                     MemoryDrawListVtxCapacity;
+    bool                    MemoryCompacted;                    // Set when window extraneous data have been garbage collected
 
 public:
     ImGuiWindow(ImGuiContext* context, const char* name);