5 files changed, 140 insertions, 22 deletions
diff --git a/common/chunk.lua b/common/chunk.lua
index 1d3faa6..affdab8 100644
--- a/common/chunk.lua
+++ b/common/chunk.lua
@@ -1,9 +1,8 @@
 local json = require"common.dkjson"
 local class = require"common.class"
+local coords = require"common.coords"
 
-local CHUNK_SIZE = 64
-
--- for now tiles shall be booleans
+local CHUNK_SIZE = require"common.constants".CHUNK_SIZE
 
 local function index_ok(offq,offr)
 	return 0<=offq and 0<=offr and offq<CHUNK_SIZE and offr<CHUNK_SIZE
@@ -17,12 +16,15 @@ local function index(offq,offr)
 end
 
 local Chunk = class()
-function Chunk.make(cls,tiles)
-	return setmetatable({tiles=tiles},cls)
+function Chunk.make(cls,cp,tiles)
+	return setmetatable({cp=cp,tiles=tiles},cls)
 end
 function Chunk.at(self,hoffs)
-	if not index_ok(hoffs.q,hoffs.r) then return nil end
-	return self.tiles[index(hoffs.q,hoffs.r)]
+	return self:_atqr(hoffs.q,hoffs.r)
+end
+function Chunk._atqr(self,q,r)
+	if not index_ok(q,r) then return nil end
+	return self.tiles[index(q,r)]
 end
 function Chunk.set_at(self,hoffs,tile)
 	if not index_ok(hoffs.q,hoffs.r) then return end
@@ -30,17 +32,18 @@ function Chunk.set_at(self,hoffs,tile)
 end
 
 function Chunk.data_packet(self)
-	return json.encode{t="chunk",tiles=self.tiles}
+	return json.encode{t="chunk",tiles=self.tiles,u=self.cp.u,v=self.cp.v}
 end
 function Chunk.from_packet_data(packet)
 	-- assuming packet has already been json.decoded
 	-- since otherwise how would we know it's a chunk packet
-	return Chunk:make(packet.tiles)
+
+	local cp = coords.ChunkPos:make(packet.u,packet.v)
+	return Chunk:make(cp,packet.tiles)
 end
 
 return {
 	Chunk=Chunk,
-	SIZE=CHUNK_SIZE,
 	index=index,
 	index_ok=index_ok,
 }
diff --git a/common/class.lua b/common/class.lua
index 37cf7bd..f5cd46e 100644
--- a/common/class.lua
+++ b/common/class.lua
@@ -1,3 +1,9 @@
+-- currently a class is a table T with T.__index = T
+-- then to make an instance of this class, we do setmetatable(instance,T)
+-- this should be fine for anything we wish to do. it is possible we will eventually
+-- split this into two separate tables though, perhaps? i don't see why we would ever
+-- do this though.
+
 local function class()
 	local T = {}
 	T.__index = T
@@ -13,6 +19,7 @@ local function extend(Base)
 		end
 	end
 	setmetatable(T,{__index=Base})
+	return T
 end
 
 return setmetatable({
diff --git a/common/constants.lua b/common/constants.lua
new file mode 100644
index 0000000..bf1bb7a
--- /dev/null
+++ b/common/constants.lua
@@ -0,0 +1,4 @@
+-- to avoid some circular dependencies
+return {
+	CHUNK_SIZE=64,
+}
diff --git a/common/coords.lua b/common/coords.lua
index 351aa53..f0ca877 100644
--- a/common/coords.lua
+++ b/common/coords.lua
@@ -1,4 +1,5 @@
 local class = require"common.class"
+local CHUNK_SIZE = require"common.constants".CHUNK_SIZE
 
 -- Hex: q,r,s. invariant that q+r+s=0
 -- add, subtract
@@ -13,15 +14,24 @@ local function round(x)
 	end
 end
 
-local Pos, Hex
+local Pos, Hex, ChunkPos
 
 local SR3 = math.sqrt(3)
 
-local Hex = class()
-function Hex.make(cls,q,r,s)
+Hex = class()
+function Hex.new(cls)
+	return setmetatable({},cls)
+end
+function Hex.init(self,q,r,s)
 	s=s or -q-r
 	assert(q+r+s==0,"hex coord doesn't meet invariant")
-	return setmetatable({q=q,r=r,s=s},cls)
+	self.q=q
+	self.r=r
+	self.s=s
+	return self
+end
+function Hex.make(cls,...)
+	return cls:new():init(...)
 end
 function Hex.round(self)
 	-- return a new Hex rounded to integer coordinates
@@ -44,20 +54,43 @@ function Hex.round(self)
 	return Hex:make(rq,rr,rs)
 end
 
-function Hex.to_pos(self)
+function Hex.to_pos(self,into)
+	into = into or Pos:new()
 	local x = self.q*SR3 + self.r*(SR3/2)
 	local y = self.r*(3/2)
-	return Pos:make(x,y)
+	return into:init(x,y)
 end
 
+function Hex.containing_chunk(self)
+	local u = math.floor(self.q/CHUNK_SIZE)
+	local v = math.floor(self.r/CHUNK_SIZE)
+	return ChunkPos:make(u,v)
+end
+function Hex.chunk_and_offset(self)
+	local cp = self:containing_chunk()
+	local tl = cp:extents()
+	return cp, (self-tl)
+end
+function Hex.offset_in_chunk(self)
+	local cp,offs = self:chunk_and_offset()
+	return offs
+end
 function Hex.__add(self,other) return Hex:make(self.q+other.q, self.r+other.r, self.s+other.s) end
 function Hex.__sub(self,other) return Hex:make(self.q-other.q, self.r-other.r, self.s-other.s) end
 function Hex.__tostring(self) return string.format("H(%.2f,%.2f)",self.q,self.r) end
-
+function Hex.__eq(a,b) return a.q==b.q and a.r==b.r end
 
 Pos = class()
-function Pos.make(cls,x,y)
-	return setmetatable({x=x,y=y},cls)
+function Pos.new(cls)
+	return setmetatable({},cls)
+end
+function Pos.init(self,x,y)
+	self.x = x
+	self.y = y
+	return self
+end
+function Pos.make(cls,...)
+	return cls:new():init(...)
 end
 function Pos.__add(self,other) return Pos:make(self.x+other.x,self.y+other.y) end
 function Pos.__sub(self,other) return Pos:make(self.x-other.x,self.y-other.y) end
@@ -74,19 +107,39 @@ function Pos.__div(a,b)
 	assert(type(b) == "number","can only divide Pos by scalar, and can't divide scalar by Pos")
 	return a*(1/b)
 end
+function Pos.__eq(a,b) return a.x==b.x and a.y==b.y end
 function Pos.lensq(self) return self.x^2 + self.y^2 end
 function Pos.len(self) return math.sqrt(self:lensq()) end
 function Pos.norm(self) return self/self:len() end
 function Pos.dot(self,other) return self.x*other.x + self.y*other.y end
-function Pos.to_hex(self)
+function Pos.to_hex(self,into)
+	into = into or Hex:new()
 	local q = self.x*(SR3/3) - self.y*(1/3)
 	local r = (2/3)*self.y
-	return Hex:make(q,r,-q-r)
+	return into:init(q,r,-q-r)
 end
 function Pos.__tostring(self) return string.format("(%.2f,%.2f)",self.x,self.y) end
 
+-- represents coordinates of a chunk
+-- ie pair of integers. the chunk at spawn is C(0,0), the one to the right of that is C(1,0), etc
+ChunkPos = class()
+function ChunkPos.make(cls,u,v)
+	return setmetatable({u=u,v=v},cls)
+end
+function ChunkPos.__add(self,other) return ChunkPos:make(self.u+other.u,self.v+other.v) end
+function ChunkPos.__sub(self,other) return ChunkPos:make(self.u-other.u,self.v-other.v) end
+function ChunkPos.__tostring(self) return string.format("C(%d,%d)",self.u,self.v) end
+function ChunkPos.__eq(a,b) return a.u==b.u and a.v==b.v end
+function ChunkPos.extents(self)
+	-- returns Hex of topleft and bottomright
+	local tlq,tlr = self.u*CHUNK_SIZE, self.v*CHUNK_SIZE
+	local brq,brr = (self.u+1)*CHUNK_SIZE -1, (self.v+1)*CHUNK_SIZE -1
+	return Hex:make(tlq,tlr), Hex:make(brq,brr)
+end
+
+
 
 
-return {Hex=Hex,Pos=Pos}
+return {Hex=Hex,Pos=Pos,ChunkPos=ChunkPos}
 
 
diff --git a/common/map.lua b/common/map.lua
index fe4b9e0..5bcd09e 100644
--- a/common/map.lua
+++ b/common/map.lua
@@ -3,4 +3,55 @@
 -- the specifics of which are then implemented separately for client and server
 -- it will probably also do things relating to entities and multiblock things
 
+local class = require"common.class"
+local chunk = require"common.chunk"
+local CHUNK_SIZE = require"common.constants".CHUNK_SIZE
 
+local Map = class()
+function Map.make(cls)
+	return setmetatable({chunks={}},cls)
+end
+function Map.add_chunk(self,cp,the_chunk)
+	print("adding chunk",cp)
+	assert(the_chunk.cp == cp,"attempting to add chunk with the wrong cp")
+	if not self.chunks[cp.u] then self.chunks[cp.u] = {} end
+	self.chunks[cp.u][cp.v] = the_chunk
+end
+function Map.unload_chunk(self,cp)
+	if not self.chunks[cp.u] then return end
+	self.chunks[cp.u][cp.v] = nil
+	-- remove list if empty
+	if next(self.chunks[cp.u]) == nil then self.chunks[cp.u] = nil end
+end
+function Map.chunk(self,cp)
+	-- return chunk at chunk coord cp
+	-- if that chunk isn't loaded return nil
+	return self:_chunkuv(cp.u,cp.v)
+end
+function Map._chunkuv(self,u,v)
+	-- same as above but with numbers instead of objects
+	-- to avoid allocations inside loop
+	return self.chunks[u] and self.chunks[u][v]
+end
+function Map.at(self,hpos)
+	-- returns tile at world coord hpos
+	-- if that tile's containing chunk isn't loaded, return nil
+
+	-- not using the methods for doing this, in order to avoid lots of allocations
+	-- inside the main drawing loop
+	local cpu,cpv = math.floor(hpos.q/CHUNK_SIZE),math.floor(hpos.r/CHUNK_SIZE)
+	local hoffq,hoffr = hpos.q-(cpu*CHUNK_SIZE), hpos.r-(cpv*CHUNK_SIZE)
+	local ch = self:_chunkuv(cpu,cpv)
+	if ch == nil then return nil end
+	return ch:_atqr(hoffq,hoffr)
+end
+function Map.set_at(self,hpos,tile)
+	local cp,hoffs = hpos:chunk_and_offset()
+	local ch = self:chunk(cp)
+	-- setting a tile in an unloaded chunk is silently ignored
+	-- this might change one day
+	if ch == nil then return nil end
+	ch:set_at(hoffs,tile)
+end
+
+return {Map=Map}