Allow rotating entity selectionboxes (#12379)

games/devtest/mods/testentities/init.lua

@@ -1,2 +1,3 @@
 dofile(minetest.get_modpath("testentities").."/visuals.lua")
+dofile(minetest.get_modpath("testentities").."/selectionbox.lua")
 dofile(minetest.get_modpath("testentities").."/armor.lua")

games/devtest/mods/testentities/selectionbox.lua

@@ -0,0 +1,96 @@
+local function color(hex)
+	return ("blank.png^[noalpha^[colorize:#%06X:255"):format(hex)
+end
+
+local function random_color()
+	return color(math.random(0, 0xFFFFFF))
+end
+
+local function random_rotation()
+	return 2 * math.pi * vector.new(math.random(), math.random(), math.random())
+end
+
+local active_selectionbox_entities = 0 -- count active entities
+
+minetest.register_entity("testentities:selectionbox", {
+	initial_properties = {
+		visual = "cube",
+		infotext = "Punch to randomize rotation, rightclick to toggle rotation"
+	},
+	on_activate = function(self)
+		active_selectionbox_entities = active_selectionbox_entities + 1
+
+		local w, h, l = math.random(), math.random(), math.random()
+		self.object:set_properties({
+			textures = {random_color(), random_color(), random_color(), random_color(), random_color(), random_color()},
+			selectionbox = {rotate = true, -w/2, -h/2, -l/2, w/2, h/2, l/2},
+			visual_size = vector.new(w, h, l),
+			automatic_rotate = 2 * math.pi * (math.random() - 0.5)
+		})
+		assert(self.object:get_properties().selectionbox.rotate)
+		self.object:set_armor_groups({punch_operable = 1})
+		self.object:set_rotation(random_rotation())
+	end,
+	on_deactivate = function()
+		active_selectionbox_entities = active_selectionbox_entities - 1
+	end,
+	on_punch = function(self)
+		self.object:set_rotation(random_rotation())
+	end,
+	on_rightclick = function(self)
+		self.object:set_properties({
+			automatic_rotate = self.object:get_properties().automatic_rotate == 0 and 2 * math.pi * (math.random() - 0.5) or 0
+		})
+	end
+})
+
+local hud_ids = {}
+minetest.register_globalstep(function()
+	if active_selectionbox_entities == 0 then
+		return
+	end
+
+	for _, player in pairs(minetest.get_connected_players()) do
+		local offset = player:get_eye_offset()
+		offset.y = offset.y + player:get_properties().eye_height
+		local pos1 = vector.add(player:get_pos(), offset)
+		local raycast = minetest.raycast(pos1, vector.add(pos1, vector.multiply(player:get_look_dir(), 10)), true, false)
+		local pointed_thing = raycast()
+		if pointed_thing.ref == player then
+			pointed_thing = raycast()
+		end
+		local remove_hud_element = true
+		local pname = player:get_player_name()
+		local hud_id = hud_ids[pname]
+		if pointed_thing and pointed_thing.type == "object" then
+			local ent = pointed_thing.ref:get_luaentity()
+			if ent and ent.name == "testentities:selectionbox" then
+				hud_ids[pname] = hud_id or player:hud_add({
+					hud_elem_type = "text",  -- See HUD element types
+					position = {x=0.5, y=0.5},
+			        text = "X",
+					number = 0xFF0000,
+					alignment = {x=0, y=0},
+				})
+				local shade = math.random(0, 0xFF)
+				minetest.add_particle({
+					-- Random shade of red for the intersection point
+					texture = color(0x10000 * shade),
+					pos = pointed_thing.intersection_point,
+					size = 0.1
+				})
+				minetest.add_particle({
+					-- Same shade of green for the corresponding intersection normal
+					texture = color(0x100 * shade),
+					pos = vector.add(pointed_thing.intersection_point, pointed_thing.intersection_normal * 0.1),
+					size = 0.1
+				})
+				remove_hud_element = false
+			end
+		end
+		if remove_hud_element and hud_id then
+			player:hud_remove(hud_id)
+			hud_ids[pname] = nil
+		end
+	end
+end)