mods that hopefully work for a TechAge-based pack

mods/techage_modpack/techage/basis/laser_lib.lua

@@ -0,0 +1,146 @@
+--[[
+
+	TechAge
+	=======
+
+	Copyright (C) 2019-2021 Joachim Stolberg
+
+	GPL v3
+	See LICENSE.txt for more information
+
+	Laser basis functions
+
+]]--
+
+local Entities = {}
+local SIZES = {1, 2, 3, 6, 12, 24, 48}  -- for laser entities
+local GAP_MIN = 1                       -- between 2 blocks
+local GAP_MAX = 2 * 48                  -- between 2 blocks
+
+-- Return the area (pos1,pos2) for a destination node
+local function get_pos_range(pos, dir)
+	local pos1 = vector.add(pos, vector.multiply(dir, GAP_MIN + 1))  -- min
+	local pos2 = vector.add(pos, vector.multiply(dir, GAP_MAX + 1))  -- max
+	return pos1, pos2
+end
+
+-- Return first pos after start pos and the destination pos
+local function get_positions(pos, mem, dir)
+	local pos1 = vector.add(pos, dir)  -- start pos
+	local _, pos2 = get_pos_range(pos, dir)  -- last pos
+	local _, pos3 = minetest.line_of_sight(pos1, pos2)
+	pos3 = pos3 or pos2  -- destination node pos
+	if not mem.peer_node_pos or not vector.equals(pos3, mem.peer_node_pos) then
+		mem.peer_node_pos = pos3
+		local dist = vector.distance(pos1, pos3)
+		if dist > GAP_MIN and dist <= GAP_MAX then
+			return true, pos1, pos3  -- new values
+		else
+			return false -- invalid values
+		end
+	end
+	return true  -- no new values
+end
+
+-- return for both laser entities the pos and length
+local function get_laser_length_and_pos(pos1, pos2, dir)
+	local dist = vector.distance(pos1, pos2)
+
+	for _, size in ipairs(SIZES) do
+		if dist <= (size * 2) then
+			pos1 = vector.add     (pos1, vector.multiply(dir, (size / 2) - 0.5))
+			pos2 = vector.subtract(pos2, vector.multiply(dir, (size / 2) + 0.5))
+			return size, pos1, pos2
+		end
+	end
+end
+
+local function del_laser(pos)
+	local key = minetest.hash_node_position(pos)
+	local items = Entities[key]
+	if items then
+		local laser1, laser2 = items[1], items[2]
+		laser1:remove()
+		laser2:remove()
+		Entities[key] = nil
+	end
+	return key
+end
+
+local function add_laser(pos, pos1, pos2, size, param2)
+	local key = del_laser(pos)
+
+	local laser1 = minetest.add_entity(pos1, "techage:laser" .. size)
+	if laser1 then
+		local yaw = math.pi / 2 * (param2 + 1)
+		laser1:set_rotation({x = 0, y = yaw, z = 0})
+	end
+
+	local laser2 = minetest.add_entity(pos2, "techage:laser" .. size)
+	if laser2 then
+		param2 = (param2 + 2) % 4  -- flip dir
+		local yaw = math.pi / 2 * (param2 + 1)
+		laser2:set_rotation({x = 0, y = yaw, z = 0})
+	end
+
+	Entities[key] = {laser1, laser2}
+end
+
+for _, size in ipairs(SIZES) do
+	minetest.register_entity("techage:laser" .. size, {
+		initial_properties = {
+			visual = "cube",
+			textures = {
+				"techage_laser.png",
+				"techage_laser.png",
+				"techage_laser.png",
+				"techage_laser.png",
+				"techage_laser.png",
+				"techage_laser.png",
+			},
+			use_texture_alpha = true,
+			physical = false,
+			collide_with_objects = false,
+			pointable = false,
+			static_save = false,
+			visual_size = {x = size, y = 0.05, z = 0.05},
+			glow = 14,
+			shaded = true,
+		},
+	})
+end
+
+-------------------------------------------------------------------------------
+-- API functions
+-------------------------------------------------------------------------------
+-- if force is not true, do not redraw the laser if nothing has changed
+function techage.renew_laser(pos, force)
+	local mem = techage.get_mem(pos)
+	if force then
+		mem.peer_node_pos = nil
+		mem.param2 = nil
+	end
+	mem.param2 = mem.param2 or minetest.get_node(pos).param2
+	local dir = minetest.facedir_to_dir(mem.param2)
+	local res, pos1, pos2 = get_positions(pos, mem, dir)
+	if pos1 then
+		local size, pos3, pos4 = get_laser_length_and_pos(pos1, pos2, dir)
+		if size then
+			add_laser(pos, pos3, pos4, size, mem.param2)
+			return res, pos1, pos2
+		end
+	end
+	return res
+end
+
+function techage.add_laser(pos, pos1, pos2)
+	local dir = vector.direction(pos1, pos2)
+	local param2 = minetest.dir_to_facedir(dir)
+	local size, pos3, pos4 = get_laser_length_and_pos(pos1, pos2, dir)
+	if size then
+		add_laser(pos, pos3, pos4, size, param2)
+	end
+end
+
+-- techage.del_laser(pos)
+techage.del_laser = del_laser