From 004f1b061ffa48f474b80a71da789dca4da599f0 Mon Sep 17 00:00:00 2001
From: peter1138 <peter1138@openttd.org>
Date: Wed, 17 Jan 2007 22:19:12 +0000
Subject: [PATCH] (svn r8211) -Codechange: (NewGRF) Implement callback 2D,
 explicit vehicle colour map selection.

---
 src/newgrf_callbacks.h |  4 ++++
 src/vehicle.cpp        | 36 ++++++++++++++++++++++++++----------
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/src/newgrf_callbacks.h b/src/newgrf_callbacks.h
index 9d0a7a3dac..edc2ea6bfe 100644
--- a/src/newgrf_callbacks.h
+++ b/src/newgrf_callbacks.h
@@ -48,6 +48,10 @@ enum CallbackID {
 	/* Called when building a station to customize the tile layout */
 	CBID_STATION_TILE_LAYOUT        = 0x24,
 
+	/* Called to determine if a specific colour map should be used for a vehicle
+	 * instead of the default livery */
+	CBID_VEHICLE_COLOUR_MAPPING     = 0x2D,
+
 	/* Called when the player (or AI) tries to start or stop a vehicle. Mainly
 	 * used for preventing a vehicle from leaving the depot. */
 	CBID_VEHICLE_START_STOP_CHECK   = 0x31,
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index 07399e1019..2ebd1e2b2c 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -33,6 +33,7 @@
 #include "network/network.h"
 #include "yapf/yapf.h"
 #include "date.h"
+#include "newgrf_callbacks.h"
 #include "newgrf_engine.h"
 #include "newgrf_sound.h"
 #include "helpers.hpp"
@@ -2813,11 +2814,25 @@ UnitID GetFreeUnitNumber(byte type)
 	return unit;
 }
 
-static SpriteID GetEngineColourMap(EngineID engine_type, PlayerID player, EngineID parent_engine_type, CargoID cargo_type)
+static SpriteID GetEngineColourMap(EngineID engine_type, PlayerID player, EngineID parent_engine_type, const Vehicle *v)
 {
-	SpriteID map;
+	SpriteID map = PAL_NONE;
 	const Player *p = GetPlayer(player);
 	LiveryScheme scheme = LS_DEFAULT;
+	CargoID cargo_type = v == NULL ? (CargoID)CT_INVALID : v->cargo_type;
+
+	/* Check if we should use the colour map callback */
+	if (HASBIT(EngInfo(engine_type)->callbackmask, CBM_COLOUR_REMAP)) {
+		uint16 callback = GetVehicleCallback(CBID_VEHICLE_COLOUR_MAPPING, 0, 0, engine_type, v);
+		/* A return value of 0xC000 is stated to "use the default two-color
+		 * maps" which happens to be the failure action too... */
+		if (callback != CALLBACK_FAILED && callback != 0xC000) {
+			map = GB(callback, 0, 14);
+			/* If bit 14 is set, then the company colours are applied to the
+			 * map else it's returned as-is. */
+			if (!HASBIT(callback, 14)) return map;
+		}
+	}
 
 	/* The default livery is always available for use, but its in_use flag determines
 	 * whether any _other_ liveries are in use. */
@@ -2894,16 +2909,19 @@ static SpriteID GetEngineColourMap(EngineID engine_type, PlayerID player, Engine
 		if (!p->livery[scheme].in_use) scheme = LS_DEFAULT;
 	}
 
-	map = HASBIT(EngInfo(engine_type)->misc_flags, EF_USES_2CC) ?
-		(SPR_2CCMAP_BASE + p->livery[scheme].colour1 + p->livery[scheme].colour2 * 16) :
-		(PALETTE_RECOLOR_START + p->livery[scheme].colour1);
+	bool twocc = HASBIT(EngInfo(engine_type)->misc_flags, EF_USES_2CC);
+
+	if (map == PAL_NONE) map = twocc ? (SpriteID)SPR_2CCMAP_BASE : (SpriteID)PALETTE_RECOLOR_START;
+
+	map += p->livery[scheme].colour1;
+	if (twocc) map += p->livery[scheme].colour2 * 16;
 
 	return map;
 }
 
 SpriteID GetEnginePalette(EngineID engine_type, PlayerID player)
 {
-	return GetEngineColourMap(engine_type, player, INVALID_ENGINE, CT_INVALID);
+	return GetEngineColourMap(engine_type, player, INVALID_ENGINE, NULL);
 }
 
 SpriteID GetVehiclePalette(const Vehicle *v)
@@ -2912,12 +2930,10 @@ SpriteID GetVehiclePalette(const Vehicle *v)
 		return GetEngineColourMap(
 			(v->u.rail.first_engine != INVALID_ENGINE && (IsArticulatedPart(v) || UsesWagonOverride(v))) ?
 				v->u.rail.first_engine : v->engine_type,
-			v->owner,
-			v->u.rail.first_engine,
-			v->cargo_type);
+			v->owner, v->u.rail.first_engine, v);
 	}
 
-	return GetEngineColourMap(v->engine_type, v->owner, INVALID_ENGINE, v->cargo_type);
+	return GetEngineColourMap(v->engine_type, v->owner, INVALID_ENGINE, v);
 }
 
 // Save and load of vehicles