Make cinecam idle waypoints runtime-manageable

Waypoints can be added/removed via chat
commands.  This makes it easier to adapt to
various "points of interest" that may evolve over
time with the world.

szutil_cinecam/README

@@ -4,8 +4,14 @@ This mod provides a more "cinematic" camera positioning system than
 szutil_watch, providing a series of 3rd-party "chase" cams that move
 via simple jumpcuts.
 
-WARNING: this mod is heavily WIP and is missing a lot of functionality
+When no players are online, the camera will switch to a mode where it
+watches the "spawn" area, or rotating through a set of waypoints that
+can be managed via chatcommands at runtime.
+
+WARNING: this mod is intentionally missing a lot of functionality
 that you would expect, like rendering the player invisible, preventing
-the player from falling or taking damage, etc.
+the player from falling or taking damage, etc.  This is the
+responsibility of other mods.  See szutil_stealth for the invisibility
+feature; the rest will be game-depenent.
 
 ------------------------------------------------------------------------

szutil_cinecam/init.lua

@@ -1,13 +1,16 @@
 -- LUALOCALS < ---------------------------------------------------------
-local ipairs, math, minetest, pairs, rawget, rawset, tonumber, type
+local ipairs, math, minetest, pairs, rawget, rawset, table, tonumber,
-    = ipairs, math, minetest, pairs, rawget, rawset, tonumber, type
+      type
+    = ipairs, math, minetest, pairs, rawget, rawset, table, tonumber,
+      type
 local math_atan2, math_ceil, math_cos, math_pi, math_random, math_sin,
-      math_sqrt
+      math_sqrt, table_concat
     = math.atan2, math.ceil, math.cos, math.pi, math.random, math.sin,
-      math.sqrt
+      math.sqrt, table.concat
 -- LUALOCALS > ---------------------------------------------------------
 
 local modname = minetest.get_current_modname()
+local modstore = minetest.get_mod_storage()
 
 local api = rawget(_G, modname) or {}
 rawset(_G, modname, api)
@@ -43,7 +46,6 @@ local defaults = {
 
 local config
 local enabled_players
-local waypoints
 
 local function reconfigure()
 	config = {}
@@ -56,16 +58,6 @@ local function reconfigure()
 			enabled_players[n] = true
 		end
 	end
-	waypoints = {}
-	local wpstr = minetest.settings:get(modname .. "_waypoints") or ""
-	if wpstr == "" then wpstr = minetest.settings:get("static_spawn") or "" end
-	for _, n in pairs(wpstr:split(';')) do
-		local xyz = n:split(",")
-		if #xyz == 3 then
-			waypoints[#waypoints + 1] = vector.new(xyz[1], xyz[2], xyz[3])
-		end
-	end
-	if #waypoints < 1 then waypoints[1] = vector.new(0, 0, 0) end
 	return true, modname .. " config reloaded"
 end
 reconfigure()
@@ -76,6 +68,80 @@ minetest.register_chatcommand(modname, {
 		func = reconfigure
 	})
 
+local waypoints
+do
+	local explicit_wps
+	local function waypoint_publish()
+		waypoints = explicit_wps
+		if #waypoints < 1 then
+			local ss = minetest.setting_get_pos("static_spawn")
+			if ss then waypoints = {ss} end
+		end
+		if #waypoints < 1 then
+			waypoints = {vector.new(0, 0, 0)}
+		end
+	end
+	do
+		local s = modstore:get_string("waypoints")
+		explicit_wps = s and minetest.deserialize(s) or {}
+		waypoint_publish()
+	end
+	local function wprm(pos)
+		for i = #explicit_wps, 1, -1 do
+			local wp = explicit_wps[i]
+			if vector.distance(wp, pos) <= 4 then
+				explicit_wps[i] = explicit_wps[#explicit_wps]
+				explicit_wps[#explicit_wps] = nil
+			end
+		end
+	end
+	local function wprpt()
+		local tbl = {modname, "waypoints:"}
+		for i = 1, #explicit_wps do
+			tbl[#tbl + 1] = minetest.pos_to_string(explicit_wps[i], 0)
+		end
+		tbl[#tbl + 1] = "total=" .. #explicit_wps
+		return true, table_concat(tbl, " ")
+	end
+	local function waypoint_rmadd(add)
+		return function(name)
+			local player = minetest.get_player_by_name(name)
+			local pos = player and player:get_pos()
+			if not pos then return false, "must be online" end
+			wprm(pos)
+			if add then explicit_wps[#explicit_wps + 1] = pos end
+			waypoint_publish()
+			modstore:set_string("waypoints", minetest.serialize(explicit_wps))
+			return wprpt()
+		end
+	end
+	minetest.register_chatcommand(modname .. "_wpls", {
+			description = "List current " .. modname .. " waypoints",
+			privs = {server = true},
+			func = wprpt
+		})
+	minetest.register_chatcommand(modname .. "_wprm", {
+			description = "Remove current location from " .. modname .. " waypoints",
+			privs = {server = true},
+			func = waypoint_rmadd()
+		})
+	minetest.register_chatcommand(modname .. "_wpset", {
+			description = "Add current location to " .. modname .. " waypoints",
+			privs = {server = true},
+			func = waypoint_rmadd(true)
+		})
+	minetest.register_chatcommand(modname .. "_wpclear", {
+			description = "Reset all " .. modname .. " waypoints",
+			privs = {server = true},
+			func = function()
+				explicit_wps = {}
+				waypoint_publish()
+				modstore:set_string("waypoints", minetest.serialize(explicit_wps))
+				return wprpt()
+			end
+		})
+end
+
 local function setcamera(player, pos, target)
 	local delta = vector.normalize(vector.subtract(target, pos))
 	player:set_look_horizontal(math_atan2(delta.z, delta.x) - math_pi / 2)