From a716b4aa28e1c2ca619677f3b507865ea80d2306 Mon Sep 17 00:00:00 2001
From: Ted John <ted@brambles.org>
Date: Sat, 16 Jun 2018 00:04:52 +0100
Subject: [PATCH] Remove use of window list in Viewport.cpp

---
 src/openrct2-ui/WindowManager.cpp      | 12 ++++++++++++
 src/openrct2/interface/Viewport.cpp    | 16 ++++++++++------
 src/openrct2/ui/DummyWindowManager.cpp |  1 +
 src/openrct2/ui/WindowManager.h        |  1 +
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/openrct2-ui/WindowManager.cpp b/src/openrct2-ui/WindowManager.cpp
index b1adeb7e0e..6ca8fb032d 100644
--- a/src/openrct2-ui/WindowManager.cpp
+++ b/src/openrct2-ui/WindowManager.cpp
@@ -502,6 +502,18 @@ public:
     {
         window_all_wheel_input();
     }
+
+    rct_window* GetOwner(const rct_viewport* viewport) override
+    {
+        for (auto w = g_window_list; w < gWindowNextSlot; w++)
+        {
+            if (w->viewport == viewport)
+            {
+                return w;
+            }
+        }
+        return nullptr;
+    }
 };
 
 IWindowManager * OpenRCT2::Ui::CreateWindowManager()
diff --git a/src/openrct2/interface/Viewport.cpp b/src/openrct2/interface/Viewport.cpp
index 9ed18a5248..e271c3bb0c 100644
--- a/src/openrct2/interface/Viewport.cpp
+++ b/src/openrct2/interface/Viewport.cpp
@@ -24,11 +24,15 @@
 #include "../world/Climate.h"
 #include "../world/Map.h"
 #include "../world/Sprite.h"
+#include "../ui/UiContext.h"
+#include "../ui/WindowManager.h"
 #include "Colour.h"
 #include "Viewport.h"
 #include "Window.h"
 #include "Window_internal.h"
 
+using namespace OpenRCT2;
+
 //#define DEBUG_SHOW_DIRTY_BOX
 uint8 gShowGridLinesRefCount;
 uint8 gShowLandRightsRefCount;
@@ -1538,14 +1542,14 @@ void viewport_invalidate(rct_viewport *viewport, sint32 left, sint32 top, sint32
     // if unknown viewport visibility, use the containing window to discover the status
     if (viewport->visibility == VC_UNKNOWN)
     {
-        for (rct_window *w = g_window_list; w < gWindowNextSlot; w++)
+        auto windowManager = GetContext()->GetUiContext()->GetWindowManager();
+        auto owner = windowManager->GetOwner(viewport);
+        if (owner != nullptr && owner->classification != WC_MAIN_WINDOW)
         {
-            if (w->classification != WC_MAIN_WINDOW && w->viewport != nullptr && w->viewport == viewport)
+            // note, window_is_visible will update viewport->visibility, so this should have a low hit count
+            if (!window_is_visible(owner))
             {
-                // note, window_is_visible will update viewport->visibility, so this should have a low hit count
-                if (!window_is_visible(w)) {
-                    return;
-                }
+                return;
             }
         }
     }
diff --git a/src/openrct2/ui/DummyWindowManager.cpp b/src/openrct2/ui/DummyWindowManager.cpp
index 870bbbb4e7..e11946d89b 100644
--- a/src/openrct2/ui/DummyWindowManager.cpp
+++ b/src/openrct2/ui/DummyWindowManager.cpp
@@ -27,6 +27,7 @@ namespace OpenRCT2::Ui
         std::string GetKeyboardShortcutString(sint32 /*shortcut*/) override { return std::string(); }
         void SetMainView(sint32 x, sint32 y, sint32 zoom, sint32 rotation) override { }
         void UpdateMouseWheel() override { }
+        rct_window* GetOwner(const rct_viewport* viewport) override { return nullptr; }
     };
 
     IWindowManager * CreateDummyWindowManager()
diff --git a/src/openrct2/ui/WindowManager.h b/src/openrct2/ui/WindowManager.h
index 61a5cd52d5..567f6d02e3 100644
--- a/src/openrct2/ui/WindowManager.h
+++ b/src/openrct2/ui/WindowManager.h
@@ -37,6 +37,7 @@ namespace OpenRCT2::Ui
         virtual std::string GetKeyboardShortcutString(sint32 shortcut) abstract;
         virtual void SetMainView(sint32 x, sint32 y, sint32 zoom, sint32 rotation) abstract;
         virtual void UpdateMouseWheel() abstract;
+        virtual rct_window* GetOwner(const rct_viewport* viewport) abstract;
     };
 
     IWindowManager * CreateDummyWindowManager();