Drag and Drop: prev/curr storage for DragDropAcceptFlags. ImGuiDragDropFlags_AcceptNoPreviewTooltip test uses DragDropAcceptFlagsPrev for consistency. (#143)

I don't think this would have materialized as a visible bug.

Author: ocornut

imgui.cpp

@@ -4190,7 +4190,7 @@ ImGuiContext::ImGuiContext(ImFontAtlas* shared_font_atlas)
     DragDropMouseButton = -1;
     DragDropTargetId = 0;
     DragDropTargetFullViewport = 0;
-    DragDropAcceptFlags = ImGuiDragDropFlags_None;
+    DragDropAcceptFlagsCurr = DragDropAcceptFlagsPrev = ImGuiDragDropFlags_None;
     DragDropAcceptIdCurrRectSurface = 0.0f;
     DragDropAcceptIdPrev = DragDropAcceptIdCurr = 0;
     DragDropAcceptFrameCount = -1;
@@ -5528,6 +5528,8 @@ void ImGui::NewFrame()
     // Drag and drop
     g.DragDropAcceptIdPrev = g.DragDropAcceptIdCurr;
     g.DragDropAcceptIdCurr = 0;
+    g.DragDropAcceptFlagsPrev = g.DragDropAcceptFlagsCurr;
+    g.DragDropAcceptFlagsCurr = ImGuiDragDropFlags_None;
     g.DragDropAcceptIdCurrRectSurface = FLT_MAX;
     g.DragDropWithinSource = false;
     g.DragDropWithinTarget = false;
@@ -14552,7 +14554,7 @@ void ImGui::ClearDragDrop()
         IMGUI_DEBUG_LOG_ACTIVEID("[dragdrop] ClearDragDrop()\n");
     g.DragDropActive = false;
     g.DragDropPayload.Clear();
-    g.DragDropAcceptFlags = ImGuiDragDropFlags_None;
+    g.DragDropAcceptFlagsCurr = ImGuiDragDropFlags_None;
     g.DragDropAcceptIdCurr = g.DragDropAcceptIdPrev = 0;
     g.DragDropAcceptIdCurrRectSurface = FLT_MAX;
     g.DragDropAcceptFrameCount = -1;
@@ -14681,7 +14683,7 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
         // Target can request the Source to not display its tooltip (we use a dedicated flag to make this request explicit)
         // We unfortunately can't just modify the source flags and skip the call to BeginTooltip, as caller may be emitting contents.
         bool ret;
-        if (g.DragDropAcceptIdPrev && (g.DragDropAcceptFlags & ImGuiDragDropFlags_AcceptNoPreviewTooltip))
+        if (g.DragDropAcceptIdPrev && (g.DragDropAcceptFlagsPrev & ImGuiDragDropFlags_AcceptNoPreviewTooltip))
             ret = BeginTooltipHidden();
         else
             ret = BeginTooltip();
@@ -14862,7 +14864,7 @@ const ImGuiPayload* ImGui::AcceptDragDropPayload(const char* type, ImGuiDragDrop
     if (r_surface > g.DragDropAcceptIdCurrRectSurface)
         return NULL;
 
-    g.DragDropAcceptFlags = flags;
+    g.DragDropAcceptFlagsCurr = flags;
     g.DragDropAcceptIdCurr = g.DragDropTargetId;
     g.DragDropAcceptIdCurrRectSurface = r_surface;
     //IMGUI_DEBUG_LOG("AcceptDragDropPayload(): %08X: accept\n", g.DragDropTargetId);

imgui_internal.h

@@ -2380,7 +2380,8 @@ struct ImGuiContext
     ImRect                  DragDropTargetClipRect;             // Store ClipRect at the time of item's drawing
     ImGuiID                 DragDropTargetId;
     ImGuiID                 DragDropTargetFullViewport;
-    ImGuiDragDropFlags      DragDropAcceptFlags;
+    ImGuiDragDropFlags      DragDropAcceptFlagsCurr;
+    ImGuiDragDropFlags      DragDropAcceptFlagsPrev;
     float                   DragDropAcceptIdCurrRectSurface;    // Target item surface (we resolve overlapping targets by prioritizing the smaller surface)
     ImGuiID                 DragDropAcceptIdCurr;               // Target item id (set at the time of accepting the payload)
     ImGuiID                 DragDropAcceptIdPrev;               // Target item id from previous frame (we need to store this to allow for overlapping drag and drop targets)