From f9a0901e8cd8e644cbf360e0192e1fd24df6cbb9 Mon Sep 17 00:00:00 2001
From: Ian Curtis <i.curtis@gmail.com>
Date: Thu, 9 Nov 2023 18:41:57 +0000
Subject: [PATCH] Fix regression Scroll attenuation seems to disable ambient
 fog. If scroll attenuation is enabled it's telling the h/w to draw the real3d
 spot light on fog for the scroll fog layer. This should fix a regression
 where the background disappears on sega rally.

---
 Src/Graphics/New3D/New3D.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Src/Graphics/New3D/New3D.cpp b/Src/Graphics/New3D/New3D.cpp
index 826fe23..55cba60 100644
--- a/Src/Graphics/New3D/New3D.cpp
+++ b/Src/Graphics/New3D/New3D.cpp
@@ -236,6 +236,10 @@ void CNew3D::DrawAmbientFog()
 			continue;
 		}
 
+		if (n.viewport.scrollAtt > 0.0f) {
+			continue;		// scroll attenuation indicates scroll fog layer
+		}
+
 		if (n.viewport.fogParams[6] < fogAmbient) {
 			nodePtr = &n;
 			fogAmbient = n.viewport.fogParams[6];