From ac06d9940811e802ab428d753ae0d8cbfe6824f3 Mon Sep 17 00:00:00 2001
From: Aaron van Geffen <aaron@aaronweb.net>
Date: Sat, 1 Mar 2025 16:10:06 +0100
Subject: [PATCH] Fix snow transitions using rain animations

---
 src/openrct2/drawing/Weather.cpp | 39 ++++++++++++++++----------------
 src/openrct2/world/Climate.cpp   |  6 +++++
 src/openrct2/world/Climate.h     |  1 +
 3 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/src/openrct2/drawing/Weather.cpp b/src/openrct2/drawing/Weather.cpp
index 340b7d76dd..4e1dedbd74 100644
--- a/src/openrct2/drawing/Weather.cpp
+++ b/src/openrct2/drawing/Weather.cpp
@@ -53,27 +53,28 @@ const DrawWeatherFunc DrawSnowFunctions[] = {
  */
 void DrawWeather(DrawPixelInfo& dpi, IWeatherDrawer* weatherDrawer)
 {
-    if (Config::Get().general.RenderWeatherEffects)
+    if (!Config::Get().general.RenderWeatherEffects)
+        return;
+
+    uint32_t viewFlags = 0;
+
+    const auto* viewport = WindowGetViewport(WindowGetMain());
+    if (viewport != nullptr)
+        viewFlags = viewport->flags;
+
+    auto weatherLevel = GetGameState().WeatherCurrent.level;
+    if (weatherLevel == WeatherLevel::None || gTrackDesignSaveMode || (viewFlags & VIEWPORT_FLAG_HIGHLIGHT_PATH_ISSUES))
+        return;
+
+    // Get weather draw function and draw weather
+    auto drawFunc = DrawRainFunctions[EnumValue(weatherLevel)];
+    if (ClimateIsSnowing() || ClimateTransitioningToSnow())
     {
-        uint32_t viewFlags = 0;
-
-        const auto* viewport = WindowGetViewport(WindowGetMain());
-        if (viewport != nullptr)
-            viewFlags = viewport->flags;
-
-        // Get weather draw function and draw weather
-        auto weatherLevel = GetGameState().WeatherCurrent.level;
-        if (weatherLevel != WeatherLevel::None && !gTrackDesignSaveMode && !(viewFlags & VIEWPORT_FLAG_HIGHLIGHT_PATH_ISSUES))
-        {
-            auto drawFunc = DrawRainFunctions[EnumValue(weatherLevel)];
-            if (ClimateIsSnowing())
-            {
-                drawFunc = DrawSnowFunctions[EnumValue(weatherLevel)];
-            }
-            auto uiContext = GetContext()->GetUiContext();
-            uiContext->DrawWeatherAnimation(weatherDrawer, dpi, drawFunc);
-        }
+        drawFunc = DrawSnowFunctions[EnumValue(weatherLevel)];
     }
+
+    auto uiContext = GetContext()->GetUiContext();
+    uiContext->DrawWeatherAnimation(weatherDrawer, dpi, drawFunc);
 }
 
 /**
diff --git a/src/openrct2/world/Climate.cpp b/src/openrct2/world/Climate.cpp
index 00c19e2d7e..f580bf291a 100644
--- a/src/openrct2/world/Climate.cpp
+++ b/src/openrct2/world/Climate.cpp
@@ -256,6 +256,12 @@ bool ClimateIsSnowing()
     return weather == WeatherType::Snow || weather == WeatherType::HeavySnow || weather == WeatherType::Blizzard;
 }
 
+bool ClimateTransitioningToSnow()
+{
+    auto& weather = GetGameState().WeatherNext.weatherType;
+    return weather == WeatherType::Snow || weather == WeatherType::HeavySnow || weather == WeatherType::Blizzard;
+}
+
 bool ClimateIsSnowingHeavily()
 {
     auto& weather = GetGameState().WeatherCurrent.weatherType;
diff --git a/src/openrct2/world/Climate.h b/src/openrct2/world/Climate.h
index ec1cbb5116..1bf2794e13 100644
--- a/src/openrct2/world/Climate.h
+++ b/src/openrct2/world/Climate.h
@@ -88,6 +88,7 @@ void ClimateForceWeather(WeatherType weather);
 enum class FilterPaletteID : int32_t;
 
 bool ClimateIsRaining();
+bool ClimateTransitioningToSnow();
 bool ClimateIsSnowing();
 bool ClimateIsSnowingHeavily();
 bool WeatherIsDry(WeatherType);