From d6a6d3176e8ea9be4224c9f1f059654e3d36ea37 Mon Sep 17 00:00:00 2001
From: Paramat <paramat@users.noreply.github.com>
Date: Thu, 24 May 2018 02:52:35 +0100
Subject: [PATCH] Schematic decorations: Fix placement bug when centred and
 rotated (#7365)

Previously, the centering caused by the 'place center x/z' flags did
not take rotation into account. So schematics with unequal X and Z
dimensions were incorrectly placed. The bug was hidden for schematics
equal in X and Z dimensions.
---
 src/mapgen/mg_decoration.cpp | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/mapgen/mg_decoration.cpp b/src/mapgen/mg_decoration.cpp
index dd621db11..6daa8216e 100644
--- a/src/mapgen/mg_decoration.cpp
+++ b/src/mapgen/mg_decoration.cpp
@@ -360,13 +360,22 @@ size_t DecoSchematic::generate(MMVManip *vm, PcgRandom *pr, v3s16 p, bool ceilin
 	if (p.Y < vm->m_area.MinEdge.Y)
 		return 0;
 
-	if (flags & DECO_PLACE_CENTER_X)
-		p.X -= (schematic->size.X - 1) / 2;
-	if (flags & DECO_PLACE_CENTER_Z)
-		p.Z -= (schematic->size.Z - 1) / 2;
-
 	Rotation rot = (rotation == ROTATE_RAND) ?
 		(Rotation)pr->range(ROTATE_0, ROTATE_270) : rotation;
+
+	if (flags & DECO_PLACE_CENTER_X) {
+		if (rot == ROTATE_0 || rot == ROTATE_180)
+			p.X -= (schematic->size.X - 1) / 2;
+		else
+			p.Z -= (schematic->size.X - 1) / 2;
+	}
+	if (flags & DECO_PLACE_CENTER_Z) {
+		if (rot == ROTATE_0 || rot == ROTATE_180)
+			p.Z -= (schematic->size.Z - 1) / 2;
+		else
+			p.X -= (schematic->size.Z - 1) / 2;
+	}
+
 	bool force_placement = (flags & DECO_FORCE_PLACEMENT);
 
 	schematic->blitToVManip(vm, p, rot, force_placement);
-- 
2.25.1