From 37e49422322ddf7c32fcb85722d915e8e2ddedb9 Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Wed, 17 Apr 2024 21:47:41 +0100
Subject: [PATCH] Add: [NewGRF] Vehicle property to copy properties of an
 existing definition.

This simplifies creation of similar variants, but can also be used for distinct types.

Strings and Action 3-2-1 chains are not copied.
---
 src/newgrf.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index 662fc3e38b..910a0cfeff 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -1334,6 +1334,16 @@ static ChangeInfoResult RailVehicleChangeInfo(uint engine, int numinfo, int prop
 				SB(ei->callback_mask, 8, 8, buf->ReadByte());
 				break;
 
+			case 0x80: { // Copy existing train properties
+				uint16_t sourceid = buf->ReadWord();
+				Engine *source = GetNewEngine(_cur.grffile, VEH_TRAIN, sourceid, true);
+				if (source == nullptr) break;
+				*ei = source->info;
+				*rvi = source->u.rail;
+				_gted[e->index] = _gted[source->index];
+				break;
+			}
+
 			default:
 				ret = CommonVehicleChangeInfo(ei, prop, buf);
 				break;
@@ -1540,6 +1550,16 @@ static ChangeInfoResult RoadVehicleChangeInfo(uint engine, int numinfo, int prop
 				SB(ei->callback_mask, 8, 8, buf->ReadByte());
 				break;
 
+			case 0x80: { // Copy existing road vehicle properties
+				uint16_t sourceid = buf->ReadWord();
+				Engine *source = GetNewEngine(_cur.grffile, VEH_ROAD, sourceid, true);
+				if (source == nullptr) break;
+				*ei = source->info;
+				*rvi = source->u.road;
+				_gted[e->index] = _gted[source->index];
+				break;
+			}
+
 			default:
 				ret = CommonVehicleChangeInfo(ei, prop, buf);
 				break;
@@ -1732,6 +1752,16 @@ static ChangeInfoResult ShipVehicleChangeInfo(uint engine, int numinfo, int prop
 				svi->acceleration = std::max<uint8_t>(1, buf->ReadByte());
 				break;
 
+			case 0x80: { // Copy existing ship properties
+				uint16_t sourceid = buf->ReadWord();
+				Engine *source = GetNewEngine(_cur.grffile, VEH_SHIP, sourceid, true);
+				if (source == nullptr) break;
+				*ei = source->info;
+				*svi = source->u.ship;
+				_gted[e->index] = _gted[source->index];
+				break;
+			}
+
 			default:
 				ret = CommonVehicleChangeInfo(ei, prop, buf);
 				break;
@@ -1897,6 +1927,16 @@ static ChangeInfoResult AircraftVehicleChangeInfo(uint engine, int numinfo, int
 				SB(ei->callback_mask, 8, 8, buf->ReadByte());
 				break;
 
+			case 0x80: { // Copy existing aircraft properties
+				uint16_t sourceid = buf->ReadWord();
+				Engine *source = GetNewEngine(_cur.grffile, VEH_AIRCRAFT, sourceid, true);
+				if (source == nullptr) break;
+				*ei = source->info;
+				*avi = source->u.air;
+				_gted[e->index] = _gted[source->index];
+				break;
+			}
+
 			default:
 				ret = CommonVehicleChangeInfo(ei, prop, buf);
 				break;