From c5af7c2480eeff15b9961d6d6904850280f542e1 Mon Sep 17 00:00:00 2001
From: Joscha <brummer@migejolise.de>
Date: Sat, 8 Apr 2017 17:05:09 +0000
Subject: [PATCH] Unload chunks that fall outside a certain radius

---
 chunks.py |  4 ++--
 maps.py   | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/chunks.py b/chunks.py
index 034ba24..6107c21 100644
--- a/chunks.py
+++ b/chunks.py
@@ -170,14 +170,14 @@ class ChunkPool():
 		for pos in coords:
 			self.unload(pos)
 	
-	def clean_up(self, except_for=[], condition=lambda chunk: True):
+	def clean_up(self, except_for=[], condition=lambda pos, chunk: True):
 		# old list comprehension which became too long:
 		#coords = [pos for pos, chunk in self._chunks.items() if not pos in except_for and condition(chunk)]
 		
 		coords = []
 		
 		for pos, chunk in self._chunks.items():
-			if not pos in except_for and condition(chunk):
+			if not pos in except_for and condition(pos, chunk):
 				coords.append(pos)
 		
 		self.unload_list(coords)
diff --git a/maps.py b/maps.py
index 2464399..043d243 100644
--- a/maps.py
+++ b/maps.py
@@ -15,7 +15,8 @@ class Map():
 	def __init__(self, width, height, chunkpool, drawevent):
 		self._lock = threading.RLock()
 		
-		self.chunkpreload = 0
+		self.chunkpreload = 0 # preload chunks in this radius (they will count as "visible")
+		self.chunkunload = 5 # don't unload chunks within this radius
 		self.cursorpadding = 2
 		self.worldx = 0
 		self.worldy = 0
@@ -77,11 +78,20 @@ class Map():
 				s = "."*CHUNK_WIDTH
 				self._pad.addstr(y+dy, x, s)
 	
+	def _unload_condition(self, pos, chunk):
+		xstart = chunkx(self.worldx) - self.chunkunload
+		ystart = chunky(self.worldy) - self.chunkunload
+		xend = xstart + chunkx(self.width)+2 + 2*self.chunkunload
+		yend = ystart + chunky(self.height)+2 + 2*self.chunkunload
+		
+		in_range = pos.x >= xstart and pos.x < xend and pos.y >= ystart and pos.y < yend
+		return not in_range
+	
 	def load_visible(self):
 		with self.chunkpool as pool:
 			coords = self.visible_chunk_coords()
 			pool.load_list(coords)
-			#pool.clean_up(except_for=coords)
+			pool.clean_up(except_for=coords, condition=self._unload_condition)
 		
 		self.drawevent.set()