(svn r20505) -Feature [FS#3978]: Allow changing visual effect when changing railtype.

1 files changed, 26 insertions, 5 deletions

diff --git a/src/train_cmd.cpp b/src/train_cmd.cpp
index 442c7d680..70c275925 100644
--- a/src/train_cmd.cpp
+++ b/src/train_cmd.cpp
@@ -130,10 +130,27 @@ void CheckTrainsLengths()
 }
 
 /**
+ * Update visual effect, power and acceleration caches.
+ * Called when a vehicle in the consist enters a different railtype.
+ */
+void Train::RailtypeChanged()
+{
+	for (Train *u = this; u != NULL; u = u->Next()) {
+		/* The wagon-is-powered-state should not change, so the weight does not change. */
+		u->UpdateVisualEffect(false);
+	}
+	this->PowerChanged();
+	if (this->IsFrontEngine()) this->UpdateAcceleration();
+}
+
+/**
  * Update the cached visual effect.
+ * @param allow_power_change true if the wagon-is-powered-state may change.
  */
-void Train::UpdateVisualEffect()
+void Train::UpdateVisualEffect(bool allow_power_change)
 {
+	byte powered_before = this->tcache.cached_vis_effect & 0x80;
+
 	const Engine *e = Engine::Get(this->engine_type);
 	if (e->u.rail.visual_effect != 0) {
 		this->tcache.cached_vis_effect = e->u.rail.visual_effect;
@@ -156,6 +173,11 @@ void Train::UpdateVisualEffect()
 
 		if (callback != CALLBACK_FAILED) this->tcache.cached_vis_effect = GB(callback, 0, 8);
 	}
+
+	if (!allow_power_change && powered_before != (this->tcache.cached_vis_effect & 0x80)) {
+		this->tcache.cached_vis_effect ^= 0x80;
+		ShowNewGrfVehicleError(this->engine_type, STR_NEWGRF_BROKEN, STR_NEWGRF_BROKEN_POWERED_WAGON, GBUG_VEH_POWERED_WAGON, false);
+	}
 }
 
 /**
@@ -215,7 +237,7 @@ void Train::ConsistChanged(bool same_length)
 		u->colourmap = PAL_NONE;
 
 		/* Update powered-wagon-status and visual effect */
-		u->UpdateVisualEffect();
+		u->UpdateVisualEffect(true);
 
 		if (rvi_v->pow_wag_power != 0 && rvi_u->railveh_type == RAILVEH_WAGON &&
 				UsesWagonOverride(u) && !HasBit(u->tcache.cached_vis_effect, 7)) {
@@ -1566,7 +1588,7 @@ static void ReverseTrainSwapVeh(Train *v, int l, int r)
 	}
 
 	/* Update power of the train in case tiles were different rail type. */
-	v->PowerChanged();
+	v->RailtypeChanged();
 }
 
 
@@ -3367,8 +3389,7 @@ static void TrainController(Train *v, Vehicle *nomove)
 					v->tile = gp.new_tile;
 
 					if (GetTileRailType(gp.new_tile) != GetTileRailType(gp.old_tile)) {
-						v->First()->PowerChanged();
-						v->First()->UpdateAcceleration();
+						v->First()->RailtypeChanged();
 					}
 
 					v->track = chosen_track;