many worldgen mods and gonna try technic now

mods/dfcaverns/df_underworld_items/crystals_amethyst.lua

@@ -0,0 +1,79 @@
+local S = minetest.get_translator(minetest.get_current_modname())
+
+minetest.register_node("df_underworld_items:glow_amethyst", {
+	description = S("Glowing Amethyst Block"),
+	_doc_items_longdesc = df_underworld_items.doc.glow_amethyst_desc,
+	_doc_items_usagehelp = df_underworld_items.doc.glow_amethyst_usage,
+	tiles = {"dfcaverns_glow_amethyst.png"},
+	is_ground_content = false,
+	groups = {cracky=3, pit_plasma_resistant=1, pickaxey = 4, building_block = 1,}, -- deliberately not in material_stone group to keep pit plasma ABM efficient
+	sounds = df_dependencies.sound_glass(),
+	light_source = 6,
+	paramtype = "light",
+	use_texture_alpha = "blend",
+	drawtype = "glasslike",
+	sunlight_propagates = true,
+	_mcl_blast_resistance = 6,
+	_mcl_hardness = 2,
+})
+
+if minetest.get_modpath("radiant_damage") and radiant_damage.override_radiant_damage and radiant_damage.config.enable_mese_damage then
+	radiant_damage.override_radiant_damage("mese", {emitted_by={["df_underworld_items:glow_amethyst"] = radiant_damage.config.mese_damage*0.25}})
+end
+
+local c_amethyst = minetest.get_content_id("df_underworld_items:glow_amethyst")
+
+local safe_write = function(data, area, vi, c_node)
+	if area:containsi(vi) then data[vi] = c_node end
+end
+
+-- x_slant and z_slant can be 1, 0 or -1
+-- rotated is true or false
+-- length is 1 or more
+df_underworld_items.underworld_shard = function(data, area, vi, x_slant, z_slant, rotated, length)
+	if x_slant == nil then x_slant = math.random(-1,1) end
+	if z_slant == nil then z_slant = math.random(-1,1) end
+	if rotated == nil then rotated = math.random() > 0.5 end
+	if length == nil then length = math.random(4, 12) end
+	
+	length = math.ceil(length/2) * 2 -- make it an even multiple of 2
+
+	local xstride, ystride, zstride
+	ystride = area.ystride
+	if rotated then
+		xstride = area.zstride
+		zstride = 1
+	else
+		xstride = 1
+		zstride = area.zstride
+	end
+	
+	-- bottom end
+	safe_write(data, area, vi, c_amethyst)
+	safe_write(data, area, vi+xstride, c_amethyst)
+	
+	for i = 1, length do
+		vi = vi + ystride
+		
+		safe_write(data, area, vi-xstride, c_amethyst)
+		
+		safe_write(data, area, vi+zstride, c_amethyst)
+		safe_write(data, area, vi, c_amethyst)
+		safe_write(data, area, vi-zstride, c_amethyst)
+
+		safe_write(data, area, vi+zstride+xstride, c_amethyst)
+		safe_write(data, area, vi+xstride, c_amethyst)
+		safe_write(data, area, vi-zstride+xstride, c_amethyst)
+
+		safe_write(data, area, vi+2*xstride, c_amethyst)
+
+		if i % 2 == 0 and i ~= length then
+			vi = vi + xstride * x_slant + zstride * z_slant
+		end
+	end
+
+	vi = vi + ystride
+	
+	safe_write(data, area, vi, c_amethyst)
+	safe_write(data, area, vi+xstride, c_amethyst)
+end