Implement infinite scrolling.

main.lua

@@ -1,6 +1,6 @@
 function _init()
    init_mapgen()
-   init_movement({block_size/2, block_size/2})
+   init_player({block_size/2, block_size/2})
    generate_map({0, 0})
    debug = false
 end
@@ -8,6 +8,7 @@ end
 
 function _update()
    handle_input()
+   handle_map_update()
    if (btn(5) and btn(4) and btnp(3)) debug = not debug
 end
 
@@ -21,14 +22,28 @@ function _draw()
    end
 end
 
+-- decide whether we need to regenerate the map.
+-- if so, call generate_map appropriately and reset coordinates.
+function handle_map_update()
+   if out_of_bounds(camera_pos) then -- out_of_bounds() checks all screen bounds
+      -- we need to regenerate the map, so we generate a map chunk that
+      -- places the player in the middle of it.
+      generate_map({player_pos[1]-block_size/2, player_pos[2]-block_size/2})
+      camera_pos = {block_size/2 - 8, block_size/2 - 8}
+   end
+end
+
+function out_of_bounds(pos)
+   return pos[1] < 0 or pos[1] > block_size-16 or pos[2] < 0 or pos[2] > block_size-16
+end
+
 function render_debug_info()
-   clip(0, 0, 32, 32)
-   rectfill(0, 0, 32, 32, 0)
+   clip(0, 0, 32, 24)
+   rectfill(0, 0, 32, 24, 0)
    print(stat(0), 0, 0, 15)
    print(camera_pos[1], 0, 8, 15)
    print(camera_pos[2], 16, 8, 15)
-   print(facing[1], 0, 16, 15)
-   print(facing[2], 16, 16, 15)
-   print(fget(mget(camera_pos[1]+8, camera_pos[2]+8)), 0, 24, 15)
+   print(player_pos[1], 0, 16, 15)
+   print(player_pos[2], 16, 16, 15)
    clip()
 end