make nature_classic aware of moretrees

If moretrees is not present, nature_classic spawns blossoms and
eventually apples on default trees, as it always has.

If moretrees IS present, the code will only spawn apple blossoms on
moretrees' own apple tree leaves, and will only grow new apples on those
trees, not on default trees.  In this case, the nature:blossom node is
considered deprecated and is aliased to default:leaves to avoid causing
undefined nodes in old maps.

nature_classic/blossom.lua

@@ -1,8 +1,18 @@
 -- Blossom
 
+local BLOSSOM_NODE = "nature:blossom"
+local BLOSSOM_LEAVES = "default:leaves"
+local BLOSSOM_TEXTURES = { "default_leaves.png^nature_blossom.png" }
+
+if minetest.get_modpath("moretrees") then
+	BLOSSOM_NODE = "moretrees:apple_blossoms"
+	BLOSSOM_LEAVES = "moretrees:apple_tree_leaves"
+	BLOSSOM_TEXTURES = { "moretrees_apple_tree_leaves.png^nature_blossom.png" }
+	minetest.register_alias("nature:blossom", "default:leaves")
+end
+
 local BLOSSOM_CHANCE = 15
 local BLOSSOM_DELAY = 3600
-local BLOSSOM_NODE = "nature:blossom"
 
 local APPLE_CHANCE = 10
 local APPLE_SPREAD = 2
@@ -19,13 +29,12 @@ local function spawn_apple_under(pos)
 end
 
 minetest.register_node(":"..BLOSSOM_NODE, {
-    description = "Blossom",
+    description = "Apple blossoms",
     drawtype = "allfaces_optional",
-    tiles = { "default_leaves.png^nature_blossom.png" },
+    tiles = BLOSSOM_TEXTURES,
     paramtype = "light",
     groups = { snappy = 3, leafdecay = 3, flammable = 2 },
     sounds = default.node_sound_leaves_defaults(),
-    drop = BLOSSOM_NODE,
 	waving = 1
 })
 
@@ -37,7 +46,7 @@ minetest.register_craft({
 
 -- Blossoming
 minetest.register_abm({
-    nodenames = { "default:leaves" },
+    nodenames = { BLOSSOM_LEAVES },
     interval = BLOSSOM_DELAY,
     chance = BLOSSOM_CHANCE,
 
@@ -55,7 +64,7 @@ minetest.register_abm({
     chance = BLOSSOM_CHANCE,
 
     action = function(pos, node, active_object_count, active_object_count_wider)
-		nature:grow_node(pos, "default:leaves")
+		nature:grow_node(pos, BLOSSOM_LEAVES)
     end
 })
 

nature_classic/depends.txt

@@ -1 +1,2 @@
 default
+moretrees?