From d90f6f01cc94d2c41ed2a96e509747be9461ebaa Mon Sep 17 00:00:00 2001
From: frosch <frosch@openttd.org>
Date: Mon, 28 Apr 2025 13:23:19 +0200
Subject: [PATCH] Codechange: CALLBACK_FAILED is an internal constant, do not
 use it as numeric value in VA2 computations.

---
 src/newgrf_spritegroup.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/newgrf_spritegroup.cpp b/src/newgrf_spritegroup.cpp
index ce75956f2b..5ae850f9fe 100644
--- a/src/newgrf_spritegroup.cpp
+++ b/src/newgrf_spritegroup.cpp
@@ -198,9 +198,10 @@ const SpriteGroup *DeterministicSpriteGroup::Resolve(ResolverObject &object) con
 		if (adjust.variable == 0x7E) {
 			const SpriteGroup *subgroup = SpriteGroup::Resolve(adjust.subroutine, object, false);
 			if (subgroup == nullptr) {
-				value = CALLBACK_FAILED;
+				value = UINT16_MAX;
 			} else {
 				value = subgroup->GetCallbackResult();
+				if (value == CALLBACK_FAILED) value = UINT16_MAX;
 			}
 
 			/* Note: 'last_value' and 'reseed' are shared between the main chain and the procedure */