ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where changing channels with different TextureId, VtxOffset would incorrectly apply new settings to draw channels. (#3129, #3163)

docs/CHANGELOG.txt

@@ -59,6 +59,9 @@ Other Changes:
 - ImDrawList: Fixed an issue where draw command merging or primitive unreserve while crossing the 
   VtxOffset boundary would lead to draw commands with wrong VtxOffset. (#3129, #3163, #3232, #2591)
   [@thedmd, @Shironekoben, @sergeyn, @ocornut]
+- ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where changing channels with different
+  TextureId, VtxOffset would incorrectly apply new settings to draw channels. (#3129, #3163)
+  [@ocornut, @thedmd, @Shironekoben]
 - ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where starting a split when current 
   VtxOffset was not zero would lead to draw commands with wrong VtxOffset. (#2591)
 - ImDrawList, ImDrawListSplitter, Columns: Fixed an issue where starting a split right after

imgui_draw.cpp

@@ -1435,8 +1435,13 @@ void ImDrawListSplitter::Merge(ImDrawList* draw_list)
     if (draw_list->CmdBuffer.Size == 0 || draw_list->CmdBuffer.back().UserCallback != NULL)
         draw_list->AddDrawCmd();
 
-    draw_list->_OnChangedClipRect(); // We call this instead of AddDrawCmd(), so that empty channels won't produce an extra draw call.
-    draw_list->_OnChangedTextureID();
+    // If current command is used with different settings we need to add a new command
+    ImDrawCmd* curr_cmd = &draw_list->CmdBuffer.Data[draw_list->CmdBuffer.Size - 1];
+    if (curr_cmd->ElemCount == 0)
+        ImDrawCmd_HeaderCopy(curr_cmd, &draw_list->_CmdHeader); // Copy ClipRect, TextureId, VtxOffset
+    else if (ImDrawCmd_HeaderCompare(curr_cmd, &draw_list->_CmdHeader) != 0)
+        draw_list->AddDrawCmd();
+
     _Count = 1;
 }
 
@@ -1453,6 +1458,13 @@ void ImDrawListSplitter::SetCurrentChannel(ImDrawList* draw_list, int idx)
     memcpy(&draw_list->CmdBuffer, &_Channels.Data[idx]._CmdBuffer, sizeof(draw_list->CmdBuffer));
     memcpy(&draw_list->IdxBuffer, &_Channels.Data[idx]._IdxBuffer, sizeof(draw_list->IdxBuffer));
     draw_list->_IdxWritePtr = draw_list->IdxBuffer.Data + draw_list->IdxBuffer.Size;
+
+    // If current command is used with different settings we need to add a new command
+    ImDrawCmd* curr_cmd = &draw_list->CmdBuffer.Data[draw_list->CmdBuffer.Size - 1];
+    if (curr_cmd->ElemCount == 0)
+        ImDrawCmd_HeaderCopy(curr_cmd, &draw_list->_CmdHeader); // Copy ClipRect, TextureId, VtxOffset
+    else if (ImDrawCmd_HeaderCompare(curr_cmd, &draw_list->_CmdHeader) != 0)
+        draw_list->AddDrawCmd();
 }
 
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