Docking+Viewports: Fixed extraneous viewport+platform-window recreation. Part 3.
Part 3: DockNodeRemoveWindow() clears viewports so it doesn't get bounced back and forth.
Note that in case of called from e.g. dock builder this can happen mid-frame. Clearing Viewport here isn't well exercised yet. If window doesn't get a Begin() in same-frame it'll be hidden.
Refer to "viewport_owner_change_1" and "viewport_owner_change_2" in ImGuiTestSuite.
Amend 6b77668171
diff --git a/imgui.cpp b/imgui.cpp
index 38a83da..30cba58 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -4407,14 +4407,14 @@
ImGuiWindow* moving_window = g.MovingWindow->RootWindowDockTree;
// When a window stop being submitted while being dragged, it may will its viewport until next Begin()
- const bool window_disappared = ((!moving_window->WasActive && !moving_window->Active) || moving_window->Viewport == NULL);
+ const bool window_disappared = (!moving_window->WasActive && !moving_window->Active);
if (g.IO.MouseDown[0] && IsMousePosValid(&g.IO.MousePos) && !window_disappared)
{
ImVec2 pos = g.IO.MousePos - g.ActiveIdClickOffset;
if (moving_window->Pos.x != pos.x || moving_window->Pos.y != pos.y)
{
SetWindowPos(moving_window, pos, ImGuiCond_Always);
- if (moving_window->ViewportOwned) // Synchronize viewport immediately because some overlays may relies on clipping rectangle before we Begin() into the window.
+ if (moving_window->Viewport && moving_window->ViewportOwned) // Synchronize viewport immediately because some overlays may relies on clipping rectangle before we Begin() into the window.
{
moving_window->Viewport->Pos = pos;
moving_window->Viewport->UpdateWorkRect();
@@ -4432,11 +4432,12 @@
UpdateTryMergeWindowIntoHostViewport(moving_window, g.MouseViewport);
// Restore the mouse viewport so that we don't hover the viewport _under_ the moved window during the frame we released the mouse button.
- if (!IsDragDropPayloadBeingAccepted())
+ if (moving_window->Viewport && !IsDragDropPayloadBeingAccepted())
g.MouseViewport = moving_window->Viewport;
// Clear the NoInput window flag set by the Viewport system
- moving_window->Viewport->Flags &= ~ImGuiViewportFlags_NoInputs; // FIXME-VIEWPORT: Test engine managed to crash here because Viewport was NULL.
+ if (moving_window->Viewport)
+ moving_window->Viewport->Flags &= ~ImGuiViewportFlags_NoInputs;
}
g.MovingWindow = NULL;
@@ -4971,6 +4972,7 @@
{
ImGuiContext& g = *GImGui;
ImGuiViewportP* viewport = window->Viewport;
+ IM_ASSERT(viewport != NULL);
g.IO.MetricsRenderWindows++;
if (window->Flags & ImGuiWindowFlags_DockNodeHost)
window->DrawList->ChannelsMerge();
@@ -15890,6 +15892,16 @@
window->ParentWindow->DC.ChildWindows.find_erase(window);
UpdateWindowParentAndRootLinks(window, window->Flags, NULL); // Update immediately
+ if (node->HostWindow && node->HostWindow->ViewportOwned)
+ {
+ // When undocking from a user interaction this will always run in NewFrame() and have not much effect.
+ // But mid-frame, if we clear viewport we need to mark window as hidden as well.
+ window->Viewport = NULL;
+ window->ViewportId = 0;
+ window->ViewportOwned = false;
+ window->Hidden = true;
+ }
+
// Remove window
bool erased = false;
for (int n = 0; n < node->Windows.Size; n++)
