Some debug code cleanup, change the format for the mod buffer key.

data.lua

@@ -49,7 +49,7 @@ function init_data()
    }
 
    -- initialize a ring buffer of changed positions. In use, this will be keyed
-   -- using strings of the form mod_buffer["x+y"], using absolute world
+   -- using strings of the form mod_buffer["x:y"], using absolute world
    -- coordinates. this is to flatten the buffer so that #mod_cache is useful
    -- for checking against max_mod_entries.
    max_mod_entries = 4096
@@ -57,13 +57,23 @@ function init_data()
 end
 
 -- x and y are global coords
+function get_mod_key(x, y)
+   return tostr(x) .. ":" .. tostr(y)
+end
+
+-- x and y are map-local coords
 function write_map_change(new_sprite, x, y)
    local global_x, global_y = calculate_world_pos(x, y)
    if #mod_buffer >= max_mod_entries then
-      -- todo: make the buffer ring
+      cull_mod_buffer()
    end
 
-   mod_buffer[tostr(global_x) .. "+" .. tostr(global_y)] = new_sprite
+   mod_buffer[get_mod_key(global_x, global_y)] = new_sprite
+end
+
+function cull_mod_buffer()
+   -- we cull 10% of the mod buffer at a time
+   -- todo: implement this
 end
 
 function calculate_world_pos(x, y)

main.lua

@@ -4,7 +4,7 @@ function _init()
    init_mapgen()
    init_player(32, 32)
    generate_map(0, 0)
-   debug = false
+   init_debug()
 end
 
 
@@ -18,9 +18,7 @@ function _draw()
    -- the screen is 128x128 pixels, so it fits 16x16 sprites
    map(camera_pos_x, camera_pos_y, 0, 0, 16, 16)
    draw_player()
-   if debug then
-      render_debug_info()
-   end
+   debug_print()
 end
 
 -- decide whether we need to regenerate the map.
@@ -40,24 +38,71 @@ function out_of_bounds(pos_x, pos_y)
       pos_y < 0 or pos_y > 48
 end
 
-function debug_res()
-   print("mem: " + stat(0))
-   print("cpu: " + stat(1))
-   print("fps: " .. stat(9) .. " / " .. stat(8))
+-- debug functions toggle debug status displays along the
+-- top of the screen
+function init_debug()
+   debug_res = false
+   debug_map = false
+   debug_sfx = false
+   debug_mod_buffer = false
 end
 
-function debug_sfx()
-   print("Music pattern: " .. stat(24))
+function debug_t(mode)
+   if mode == "res" then
+      debug_res = not debug_res
+   elseif mode == "map" then
+      debug_map = not debug_map
+   elseif mode == "sfx" then
+      debug_sfx = not debug_sfx
+   elseif mode == "" then
+      debug_mod_buffer = not debug_mod_buffer
+   end
 end
 
-function debug_map()
-   print("Local: " .. camera_pos_x .. " " .. camera_pos_y)
-   print("Global: " .. player_pos_x .. " " .. player_pos_y)
-   print(get_biome_name(player_pos_x, player_pos_y))
+function debug_print()
+   if debug_res then
+      debug_print_res()
    end
 
-function debug_mod_buffer()
+   if debug_map then
+      debug_print_map()
+   end
+
+   if debug_sfx then
+      debug_print_sfx()
+   end
+
+   if debug_mod_buffer then
+      debug_print_mod_buffer()
+   end
+end
+
+function debug_print_res()
+   clip(70, 0, 16, 24)
+   print(stat(0), 70, 0, 15)
+   print(stat(1), 70, 8, 15)
+   print(stat(9) .. " / " .. stat(8), 70, 16, 15)
+   clip()
+end
+
+function debug_print_sfx()
+   clip(64, 0, 8, 8)
+   print(stat(24), 64, 0, 15)
+   clip()
+end
+
+function debug_print_map()
+   clip(24, 0, 32, 24)
+   print(camera_pos_x .. " " .. camera_pos_y, 24, 0, 15)
+   print(player_pos_x .. " " .. player_pos_y, 24, 8, 15)
+   print(get_biome_name(player_pos_x, player_pos_y), 24, 16, 15)
+   clip()
+end
+
+function debug_print_mod_buffer()
+   clip(0, 0, 16, 128)
    for k,v in pairs(mod_buffer) do
       print(k .. ": " .. tostr(v))
    end
+   clip()
 end

mapgen.lua

@@ -90,7 +90,7 @@ end
 -- pos_x and pos_y are global coordinates.
 function get_tile(pos_x, pos_y)
    -- lookup changes in the change buffer
-   local modded_sprite = mod_buffer[tostr(pos_x) .. "+" .. tostr(pos_y)]
+   local modded_sprite = mod_buffer[get_mod_key(pos_x, pos_y)]
    if (modded_sprite) return modded_sprite
 
    local biome_name = get_biome_name(pos_x, pos_y)