spotlights: proof of concept, based of code from beacons mod

README

+Spotlights Mod
+by Peter Nerlich
+
+Implementation inspired by Beacons and Illumination mods.
+
+This mod adds spotlights - light sources that shine light to a spot over a long distance.

depends.txt

+default?
\ No newline at end of file

init.lua

+-- Maximum number of light nodes beyond spotlight
+local spotlight_undiminishing_distance = tonumber(minetest.settings:get("spotlight_undiminishing_distance")) or 12
+local spotlight_decaying_distance = tonumber(minetest.settings:get("spotlight_decaying_distance")) or 13
+local spotlight_base_shimmer = tonumber(minetest.settings:get("spotlight_base_shimmer")) or 3
+local spotlight_beam_shimmer = tonumber(minetest.settings:get("spotlight_beam_shimmer")) or 2
+local spotlight_permeate_paramtype_light = minetest.settings:get_bool("spotlight_permeate_paramtype_light", true)
+
+
+local perfectly_transparent_nodes = {
+	'default:glass', 'xpanes:pane_flat', 'doors:door_glass', 'basic_signs:sign_glass_yard',
+	'default:obsidian_glass', 'xpanes:obsidian_pane_flat', 'doors:door_obsidian_glass', 'basic_signs:sign_glass_yard',
+	'building_blocks:woodglass',
+	'moreblocks:clean_glass', 'moreblocks:coal_glass', 'moreblocks:iron_glass', 'moreblocks:glow_glass', 'moreblocks:super_glow_glass',
+
+	'butterflies:butterfly_red', 'butterflies:butterfly_violet', 'butterflies:butterfly_white', '	fireflies:firefly',
+
+	'elevators:rail', 'elevators:brakerail',
+	'farming:beanpole',
+
+	'mesecons_torch:mesecon_torch_on', 'mesecons_torch:mesecon_torch_off',
+	'mesecons_insulated:insulated_on', 'mesecons_insulated:insulated_off',
+}
+
+local x = nil
+
+function toBits(num)
+	-- returns a table of bits, least significant first.
+	local t={} -- will contain the bits
+	while num>0 do
+		local rest=math.fmod(num,2)
+		t[#t+1]=rest
+		num=(num-rest)/2
+	end
+	return t
+end
+
+for x = 0, 255 do
+	local s = 'mesecons:wire_'
+	local bits = toBits(x)
+	bits = string.reverse(table.concat(bits))
+	while #bits < 8 do
+		bits = '0'..bits
+	end
+	--print('perfectly_transparent_nodes: inserting '..s..bits..'_...')
+	table.insert(perfectly_transparent_nodes, s..'_on')
+	table.insert(perfectly_transparent_nodes, s..'_off')
+end
+
+-- reform perfectly_transparent_nodes to be easily searchable with the form
+-- name = true
+local i = nil
+local tmp = perfectly_transparent_nodes
+perfectly_transparent_nodes = {}
+for i = 1, #tmp do
+	perfectly_transparent_nodes[tmp[i]] = tmp[i]
+end
+
+
+-- end populating perfectly_transparent_nodes --
+
+
+
+local function dump(o, indent)
+	if indent == nil then indent = 0 end
+	local function idt(n)
+		if n == nil then n = 0 end
+		return string.rep('  ', indent+n)
+	end
+
+	if type(o) == 'table' then
+		local s = '{\n' -- omit indentation on opening bracket: if nested, we are not starting a line here; if not, indent is 0 anyways
+		for k,v in pairs(o) do
+			s = s..idt(1) .. dump(k, indent+1) .. ' = ' .. dump(v, indent+1) .. ',\n'
+		end
+		return s..idt() .. '} '
+	elseif type(o) ~= 'number' then
+		return '"'..tostring(o)..'"'
+	else
+		return tostring(o)
+	end
+end
+
+local function merge_tables(t1, t2)
+	local t = table.copy(t1)
+	for k,v in pairs(t2) do
+		t[k] = v
+	end
+	return t
+end
+
+
+local function get_base_under_light(pos)
+	pos = table.copy(pos)
+	local y_dist = 0
+	local node = minetest.get_node(pos)
+	while minetest.get_item_group(node.name, "spotlights_base") == 0 and (spotlight_undiminishing_distance == 0 or y_dist <= spotlight_undiminishing_distance+spotlight_decaying_distance) do
+		pos = vector.subtract(pos, {x = 0, y = 1, z = 0})
+		y_dist = y_dist + 1
+		node = minetest.get_node(pos)
+	end
+	return pos
+end
+
+
+local function spotlight_on_construct(pos_this, pos_base_under_light)
+	local pos_above = vector.add(pos_this, {x = 0, y = 1, z = 0})
+	local pos_above_that = vector.add(pos_above, {x = 0, y = 1, z = 0})
+	local pos_below = vector.subtract(pos_this, {x = 0, y = 1, z = 0})
+	if pos_base_under_light == nil then pos_base_under_light = get_base_under_light(pos_this) end
+
+	local node_this = minetest.get_node(pos_this)
+	local node_above = minetest.get_node(pos_above)
+	local node_above_that = minetest.get_node(pos_above_that)
+	local node_below = minetest.get_node(pos_below)
+	local node_base_under_light = minetest.get_node(pos_base_under_light)
+
+
+	if node_base_under_light.name == ("spotlights:base") then
+		local distance = vector.distance(pos_base_under_light, pos_above)
+		
+		if distance <= spotlight_undiminishing_distance + spotlight_decaying_distance then
+			--print('setting light at '..distance)
+			
+			if distance <= spotlight_undiminishing_distance then
+				if node_above.name == "air" or minetest.get_item_group(node_above.name, "spotlights_beam") ~= 0 then
+					if node_above_that.name ~= "air" and minetest.get_item_group(node_above_that.name, "spotlights_beam") == 0 and (not spotlight_permeate_paramtype_light or not perfectly_transparent_nodes[node_above_that.name]) then
+						if node_above.name ~= "spotlights:beam_"..minetest.LIGHT_MAX then
+							print('spotlight '..distance..': lvl '..minetest.LIGHT_MAX..' (spotlight hit full force!) || '..node_above.name..', '..node_above_that.name)
+							minetest.set_node(pos_above, {name = "spotlights:beam_"..minetest.LIGHT_MAX})
+						end
+					else
+						if distance <= 2 then
+							if node_above.name ~= "spotlights:beam_hot" then
+								print('spotlight '..distance..': HOT!! || '..node_above.name)
+								minetest.set_node(pos_above, {name = "spotlights:beam_hot"})
+							end
+						else
+							if node_above.name ~= "spotlights:beam_"..spotlight_beam_shimmer then
+								print('spotlight '..distance..': lvl '..spotlight_beam_shimmer..' || '..node_above.name)
+								minetest.set_node(pos_above, {name = "spotlights:beam_"..spotlight_beam_shimmer})
+							end
+						end
+					end
+				elseif spotlight_permeate_paramtype_light and minetest.registered_nodes[node_above.name].paramtype == 'light' then
+					-- permeate through
+					print('spotlight permeating through '..node_above.name..'... ('..distance..')')
+					spotlight_on_construct(pos_above)
+				else
+					if node_this.name ~= "spotlights:beam_"..minetest.LIGHT_MAX then
+						print('spotlight '..(distance-1)..' GLITCH: should be spotlights:beam_'..minetest.LIGHT_MAX..' but is '..node_this.name)
+					end
+				end
+			else
+				local leftover_light_level = math.ceil((1 - (distance - spotlight_undiminishing_distance) / (spotlight_decaying_distance+1)) * (minetest.LIGHT_MAX-1))
+
+				if node_above.name == "air" or minetest.get_item_group(node_above.name, "spotlights_beam") ~= 0 then
+					if node_above_that.name ~= "air" and minetest.get_item_group(node_above_that.name, "spotlights_beam") == 0 then
+						if node_above.name ~= "spotlights:beam_"..leftover_light_level then
+							print('spotlight '..distance..': lvl '..leftover_light_level..' (spotlight hit!) || '..node_above.name..', '..node_above_that.name)
+							minetest.set_node(pos_above, {name = "spotlights:beam_"..leftover_light_level})
+						end
+					else
+						local leftover_beam = math.min(spotlight_beam_shimmer, math.ceil(leftover_light_level/2))
+						if node_above.name ~= "spotlights:beam_" .. leftover_beam then
+							print('spotlight '..distance..': lvl '..leftover_beam..' (decaying to '..leftover_light_level..') || '..node_above.name)
+							minetest.set_node(pos_above, {name = "spotlights:beam_" .. leftover_beam})
+						end
+					end
+				elseif spotlight_permeate_paramtype_light and minetest.registered_nodes[node_above.name].paramtype == 'light' then
+					-- permeate through
+					spotlight_on_construct(pos_above)
+				else
+					--[[if node_this ~= "spotlights:beam_"..leftover_light_level or node_this ~= "spotlights:beam_"..(leftover_light_level+1) then
+						-- checking for leftover_light_level+1 as well, as this is set on the previous node and thus we might be 1 too low now
+						print('spotlight '..distance..': GLITCH: should be around spotlights:beam_'..leftover_light_level..' but is '..node_this.name)
+					end]]--
+				end
+			end
+		end
+	end
+end
+
+local function spotlight_on_destruct(pos)
+	local above = vector.add(pos, {x = 0, y = 1, z = 0})
+	local below = vector.subtract(pos, {x = 0, y = 1, z = 0})
+	if minetest.get_item_group(minetest.get_node(above).name, "spotlights_beam") ~= 0 and (not spotlight_permeate_paramtype_light or minetest.registered_nodes[minetest.get_node(below).name].paramtype ~= 'light') then
+		minetest.remove_node(above)
+	end
+end
+
+local function spotlight_on_destruct_base(pos)
+	local above = vector.add(pos, {x = 0, y = 1, z = 0})
+	if minetest.get_item_group(minetest.get_node(above).name, "spotlights_beam") ~= 0 then
+		minetest.remove_node(above)
+	end
+end
+
+local function spotlight_on_timer(pos)
+	local pos_base_under_light = get_base_under_light(pos)
+	if minetest.get_node(pos_base_under_light).name ~= "spotlights:base" then
+		minetest.remove_node(pos)
+	else
+		spotlight_on_construct(pos, pos_base_under_light)
+	end
+	return true
+end
+
+local function make_on_construct()
+	return function(pos)
+		minetest.get_node_timer(pos):start(1)
+		return spotlight_on_construct(pos)
+	end
+end
+
+local function make_on_destruct()
+	return function(pos) 
+		return spotlight_on_destruct(pos)
+	end
+end
+
+local function make_on_timer()
+	return function(pos) 
+		return spotlight_on_timer(pos)
+	end
+end
+
+minetest.register_node("spotlights:base", {
+	description = "Spotlight",
+	tiles = {"beacons_base_top.png", "beacons_base_bottom.png", "beacons_base_side.png"},
+	groups = {spotlights_base = 1, cracky = 2},
+	is_ground_content = false,
+	paramtype = "light",
+	light_source = spotlight_base_shimmer,
+	on_rotate = function() end, -- TODO
+	
+	on_construct = make_on_construct(),
+	on_destruct = make_on_destruct_base(),
+	on_timer = make_on_timer(),
+})
+
+if minetest.get_modpath("default") then
+	minetest.override_item("spotlights:base", {sounds = default.node_sound_metal_defaults()})
+
+	minetest.register_craft({
+		output = "spotlights:base",
+		recipe = {
+			{"default:steel_ingot", "default:meselamp", "default:steel_ingot",},
+			{"default:steel_ingot", "default:meselamp", "default:steel_ingot",},
+			{"default:steel_ingot", "default:steel_ingot", "default:steel_ingot",},
+		},
+	})
+end
+
+
+local lightPoint = {
+	drawtype = "airlike",
+--		drawtype = "plantlike",
+--		tiles = {"beacons_light.png"},
+	paramtype = "light",
+	groups = {spotlights_beam = 1, not_in_creative_inventory = 1},
+	sunlight_propagates = true,
+	can_dig = false,
+	walkable = false,
+	buildable_to = true,
+	selection_box = {
+		type = "fixed",
+		fixed = {0, 0, 0, 0, 0, 0},
+	},
+
+	on_blast = function() end,
+	
+	on_construct = make_on_construct(),
+	on_destruct = make_on_destruct(),
+	on_timer = make_on_timer(),
+}
+
+minetest.register_node("spotlights:beam_hot", merge_tables(lightPoint, {
+	light_source = spotlight_base_shimmer,
+	damage_per_second = 1,
+}))
+
+for strength=1,minetest.LIGHT_MAX do
+	--print('register_node spotlights:beam_'..strength..' (max: '..minetest.LIGHT_MAX..')')
+	minetest.register_node("spotlights:beam_" .. strength, merge_tables(lightPoint, {
+		light_source = strength,
+	}))
+	--print('registered spotlights:beam_'..strength..':\n'..dump(merge_tables(lightPoint, {
+	--	light_source = strength,
+	--})))
+end

mod.conf

+name = spotlights
+description = "Adds spotlights - light sources that shine light to a spot over a long distance."
\ No newline at end of file

settingtypes.txt

+# Spotlights will carry over a certain distance without diminishing, and then decay in strength.
+spotlight_undiminishing_distance (Spotlight undiminishing distance) int 12
+
+# Spotlights will carry over a certain distance without diminishing, and then decay in strength.
+spotlight_decaying_distance (Spotlight decaying distance) int 13
+
+# The beam of the spotlight will cast a bright light when hitting a block, and only shimmer dimly before that.
+spotlight_base_shimmer (Spotlight base shimmer) int 3
+
+
+# The beam of the spotlight will cast a bright light when hitting a block, and only shimmer dimly before that.
+spotlight_beam_shimmer (Spotlight beam shimmer) int 2
+
+# Spotlights can continue to shine through nodes like glass, plants etc. Most still produce a bright light when hit, selected ones (like glass) do not.
+spotlight_permeate_paramtype_light (Spotlight permeates through nodes of paramtype "light") bool true
\ No newline at end of file