Adding macros so that keep graphics are now selected...

...according to the adjacent castle tiles.

data/terrain-graphics.cfg

@@ -76,11 +76,15 @@
 
 # Special transitions go first
 
-# Castle and keeps
-{CASTLE_AND_KEEP C K castle keep}
+# Castle and keeps. Always use the same letter for keeps: the CASTLE_AND_KEEP
+# macro will determine the correct graphics to use, according to the adjacent
+# castle letter.
 
-# Encampment sample
-#{CASTLE_WALLS nK !nK encampment}
+#define KEEP_TILE
+K
+#enddef
+{CASTLE_AND_KEEP C {KEEP_TILE} castle keep}
+{CASTLE_AND_KEEP e {KEEP_TILE} encampment tent}
 
 # Forest, hills and mountains should always overlay on northern sides
 {TERRAIN_ADJACENT_NORTH m mountains}

data/terrain-graphics/castles.cfg

@@ -62,6 +62,9 @@
 # dynamically-drawn keeps.
 
 #define CASTLE_AND_KEEP CASTLE KEEP CASTLE_IMAGE KEEP_IMAGE
+
+# Keep rules will only work if the keep is adjacent to a castle tile.
+{FLAG_IF_ADJACENT {KEEP} {CASTLE} keep-of-{CASTLE}}
 {CASTLE_WALLS {CASTLE} !{CASTLE}{KEEP} {CASTLE_IMAGE}}
 {DISABLE_TRANSITIONS {KEEP}}
 
@@ -73,6 +76,7 @@
 	[tile]
 		pos=1
 		type={KEEP}
+		has_flag=keep-of-{CASTLE}
 	[/tile]
 	[tile]
 		pos=2
@@ -99,6 +103,7 @@
 	[tile]
 		pos=1
 		type={KEEP}
+		has_flag=keep-of-{CASTLE}
 	[/tile]
 	[tile]
 		pos=3
@@ -126,6 +131,7 @@
 	[tile]
 		pos=1
 		type={KEEP}
+		has_flag=keep-of-{CASTLE}
 	[/tile]
 	[tile]
 		pos=2
@@ -157,6 +163,7 @@
 	[tile]
 		pos=1
 		type={KEEP}
+		has_flag=keep-of-{CASTLE}
 	[/tile]
 	[tile]
 		pos=2

data/terrain-graphics/util.cfg

@@ -42,4 +42,28 @@
 [/terrain_graphics]
 #enddef
 
+# This utility macro sets a flag on a given terrain, if it is adjacent to an
+# other terrain.
+# Example:
+# {FLAG_IF_ADJACENT K C keep-of-castle} makes flags all K tiles adjacent to C
+# tiles with the keep-of-castle flag
+# 
+# Use this to make other rule depend on adjacent terrain
+
+#define FLAG_IF_ADJACENT LETTER ADJACENT FLAG
+[terrain_graphics]
+	[tile]
+		x=0
+		y=0
+		type={LETTER}
+		set_flag={FLAG}
+	[/tile]
+	[tile]
+		x=0
+		y=1
+		type={ADJACENT}
+	[/tile]
+	rotations=x,x,x,x,x,x
+[/terrain_graphics]
+#enddef