From e2d9a44a5dfd84e89bce210d4be230f794563124 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=CE=B6eh=20Matt?= <5415177+ZehMatt@users.noreply.github.com>
Date: Fri, 25 Apr 2025 17:46:30 +0300
Subject: [PATCH] Fix stray pixels showing up when panning and moving a windows

---
 .../drawing/engines/opengl/OpenGLDrawingEngine.cpp          | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp b/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp
index 73ea92a35e..48c99a424d 100644
--- a/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp
+++ b/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp
@@ -361,16 +361,20 @@ public:
     void PaintWindows() override
     {
         WindowResetVisibilities();
-        WindowUpdateAllViewports();
 
         if (ClimateIsRaining() || ClimateIsSnowing() || ClimateIsSnowingHeavily())
         {
+            WindowUpdateAllViewports();
             // OpenGL doesn't support restoring pixels, always redraw.
             // TODO: Render the weather to a texture and use that instead.
             WindowDrawAll(_bitsDPI, 0, 0, static_cast<int32_t>(_width), static_cast<int32_t>(_height));
         }
         else
         {
+            // Redraw dirty regions before updating the viewports, otherwise
+            // when viewports get panned, they copy dirty pixels
+            DrawAllDirtyBlocks();
+            WindowUpdateAllViewports();
             DrawAllDirtyBlocks();
         }
     }