Add ViewportGetMain

src/openrct2/interface/Viewport.cpp

@@ -229,6 +229,16 @@ void ViewportRemove(Viewport* viewport)
     _viewports.erase(it);
 }
 
+Viewport* ViewportGetMain()
+{
+    auto mainWindow = WindowGetMain();
+    if (mainWindow == nullptr)
+    {
+        return nullptr;
+    }
+    return mainWindow->viewport;
+}
+
 void ViewportsInvalidate(const ScreenRect& screenRect, ZoomLevel maxZoom)
 {
     for (auto& vp : _viewports)

src/openrct2/interface/Viewport.h

@@ -129,6 +129,7 @@ void ViewportInitAll();
 std::optional<ScreenCoordsXY> centre_2d_coordinates(const CoordsXYZ& loc, Viewport* viewport);
 void ViewportCreate(WindowBase* w, const ScreenCoordsXY& screenCoords, int32_t width, int32_t height, const Focus& focus);
 void ViewportRemove(Viewport* viewport);
+Viewport* ViewportGetMain();
 void ViewportsInvalidate(const ScreenRect& screenRect, ZoomLevel maxZoom = ZoomLevel{ -1 });
 void ViewportUpdatePosition(WindowBase* window);
 void ViewportUpdateFollowSprite(WindowBase* window);