block default classic texture, better opal mineral

and now uses a minetest.conf setting (see readme)

README.md

@@ -22,7 +22,10 @@ Some major changes were done to make the mod easier to maintain:
 
 ## Changes:
 '!' is for bugs in 2012 version that are fixed (as opposed to features that were changed/added) in this fork
-* (2017-03-11) added better placeholder textures for gems where prerendered block is not finished yet
+* (2017-03-13) textures improved: opal mineral overlay, alexandrite classic block
+* (2017-03-13) default block style changed to classic
+* (2017-03-13) now uses settings from server's minetest.conf: birthstones_texture_style (can be realistic or classic)
+* (2017-03-11) added better classic textures for gems where realistic block is not finished yet
 * (2017-03-11) added new texture for emerald: mineral, item
 * (2017-03-10) changed sun square emission from 10 to 100
 * (2017-03-10) new textures for "white diamond": mineral, item [blend file: octagon beveled all but top and bottom by .12 offset]; for topaz: mineral

nodes.lua

@@ -1,4 +1,34 @@
 -- START RAW MATERIALS
+
+local texture_style = minetest.setting_get("birthstones_texture_style") or "classic"
+-- can also be "realistic" if all block textures are implemented
+
+function file_exists(name)
+	local f=io.open(name,"r")
+	if f~=nil then
+		io.close(f)
+		return true
+	else return false
+	end
+end
+
+local function get_block_tiles(name)
+	local this_texture_style = texture_style
+	local path = nil
+	if this_texture_style == "realistic" then
+		-- if file_exists("birthstones_" .. name .. "_block_top.png") then
+			path = { "birthstones_" .. name .. "_block_top.png", "birthstones_" .. name .. "_block_top.png", "birthstones_" .. name .. "_block_east.png", "birthstones_" .. name .. "_block_east.png", "birthstones_" .. name .. "_block_north.png", "birthstones_" .. name .. "_block_north.png" }
+		-- else
+		-- 	this_texture_style = "classic"
+		-- end
+	end
+	-- intentionally don't use else since fallback to classic may have been performed above:
+	if this_texture_style == "classic" then
+		path = { "birthstones_" .. name .. "_block.png" }
+	end
+	return path
+end
+
 minetest.register_node( "birthstones:stone_with_alexandrite", {
 	description = "Stone with Alexandrite",
 	tiles = { "default_stone.png^birthstones_mineral_alexandrite.png" },
@@ -104,70 +134,70 @@ minetest.register_node( "birthstones:stone_with_zircon", {
 
 minetest.register_node( "birthstones:alexandriteblock", {
 	description = "Alexandrite Block",
-	tiles = { "birthstones_alexandrite_block_top.png", "birthstones_alexandrite_block_top.png", "birthstones_alexandrite_block_east.png", "birthstones_alexandrite_block_east.png", "birthstones_alexandrite_block_north.png", "birthstones_alexandrite_block_north.png" },
+	tiles = get_block_tiles("alexandrite"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:amethystblock", {
 	description = "Amethyst Block",
-	tiles = { "birthstones_amethyst_block_top.png", "birthstones_amethyst_block_top.png", "birthstones_amethyst_block_east.png", "birthstones_amethyst_block_east.png", "birthstones_amethyst_block_north.png", "birthstones_amethyst_block_north.png" },
+	tiles = get_block_tiles("amethyst"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:aquamarineblock", {
 	description = "Aquamarine Block",
-	tiles = { "birthstones_aquamarine_block_top.png", "birthstones_aquamarine_block_top.png", "birthstones_aquamarine_block_east.png", "birthstones_aquamarine_block_east.png", "birthstones_aquamarine_block_north.png", "birthstones_aquamarine_block_north.png" },
+	tiles = get_block_tiles("aquamarine"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:diamondblock", {
 	description = "White Diamond Block",
-	tiles = { "birthstones_diamond_block_top.png", "birthstones_diamond_block_top.png", "birthstones_diamond_block_east.png", "birthstones_diamond_block_east.png", "birthstones_diamond_block_north.png", "birthstones_diamond_block_north.png" },
+	tiles = get_block_tiles("diamond"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:emeraldblock", {
 	description = "Emerald Block",
-	tiles = { "birthstones_emerald_block.png" },
+	tiles = get_block_tiles("emerald"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:garnetblock", {
 	description = "Garnet Block",
-	tiles = { "birthstones_garnet_block.png" },
+	tiles = get_block_tiles("garnet"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:opalblock", {
 	description = "Opal Block",
-	tiles = { "birthstones_opal_block.png" },
+	tiles = get_block_tiles("opal"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:peridotblock", {
 	description = "Peridot Block",
-	tiles = { "birthstones_peridot_block.png" },
+	tiles = get_block_tiles("peridot"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:rubyblock", {
 	description = "Ruby Block",
-	tiles = { "birthstones_ruby_block.png" },
+	tiles = get_block_tiles("ruby"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:sapphireblock", {
 	description = "Sapphire Block",
-	tiles = { "birthstones_sapphire_block.png" },
+	tiles = get_block_tiles("sapphire"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
@@ -175,14 +205,14 @@ minetest.register_node( "birthstones:sapphireblock", {
 -- tiles: +Y, -Y, +X, -X, +Z, -Z. In English: top, bottom, right, left, back, front.  - http://dev.minetest.net/minetest.register_node
 minetest.register_node( "birthstones:topazblock", {
 	description = "Topaz Block",
-	tiles = { "birthstones_topaz_block_top.png", "birthstones_topaz_block_top.png", "birthstones_topaz_block_east.png", "birthstones_topaz_block_east.png", "birthstones_topaz_block_north.png", "birthstones_topaz_block_north.png" },
+	tiles = get_block_tiles("topaz"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),
 })
 minetest.register_node( "birthstones:zirconblock", {
 	description = "Zircon Block",
-	tiles = { "birthstones_zircon_block.png" },
+	tiles = get_block_tiles("zircon"),
 	is_ground_content = true,
 	groups = {cracky = 1, level = 3},
 	sounds = default.node_sound_stone_defaults(),