Add marker registration function and support for multi-detail markers

init.lua

@@ -8,6 +8,7 @@ _cartographer = {
     CHUNK_SIZE = 16,
 
     biome_lookup = {},
+    marker_lookup = {},
     maps = minetest.deserialize(mod_storage:get_string("maps")) or {},
     next_map_id = mod_storage:get_int("next_map_id"),
 

map_api.lua

@@ -134,6 +134,19 @@ function cartographer.register_biome(name, textures, min_height, max_height)
     };
 end
 
+-- Register a marker with textures to display
+-- id: A string containing the id of the marker
+-- name: A string containing the displayedname of the marker
+-- textures: A table of texture names.
+--           These should correspond with detail levels,
+--           any detail level past the length of the table will return the last texture
+function cartographer.register_marker(id, name, textures)
+    _cartographer.marker_lookup[id] = {
+        name = name,
+        textures = textures,
+    };
+end
+
 function cartographer.is_filled(map, x, z)
     if map == nil then
         return false;
@@ -157,3 +170,17 @@ function cartographer.get_biome_texture(name, height, detail)
 
     return nil;
 end
+
+-- Get the texture name (minus extension) for the given marker and detail level.
+-- id: A string containing the marker id
+-- detail: The detail level
+-- Returns a string with a texture name, or nil if no matching marker was found.
+function cartographer.get_marker_texture(id, detail)
+    local marker = _cartographer.marker_lookup[id];
+
+    if marker then
+        return marker.textures[math.min(detail, #marker.textures)];
+    end
+
+    return nil;
+end

map_formspec.lua

@@ -51,7 +51,7 @@ local function generate_map(data, x, y, w, h, player_x, player_y, detail, map_sc
                 end
 
                 if get_marker then
-                    local marker = get_marker(user, i, j);
+                    local marker = cartographer.get_marker_texture(get_marker(user, i, j), detail);
                     if marker then
                         str = str..tile:format(fx, fy - (height * 0.05), scale, scale, marker .. ".png")
                     end