commit 97461df05047789b7cff90fa81710a427744a78b
Author: Leslie Krause <rkrause@inbox.com>
Date:   Sun Apr 19 23:24:00 2020 -0400

    Build 01

diff --git a/README.txt b/README.txt
new file mode 100644
index 0000000..a81c927
--- /dev/null
+++ b/README.txt
@@ -0,0 +1,109 @@
+Extended Motion Mechanics for LuaEntitySAOs
+----------------------------------------------
+
+I developed this mod for interactively testing additional API methods and callbacks for 
+LuaEntitySAOs. I recommend using it with the Minimal Development Test, since it expects a 
+singlenode mapgen.
+
+In order to use this mod, you will need to compile Minetest with the folloing patch:
+https://github.com/sorcerykid/minetest/tree/extend-entity-api
+
+After joining the game, type `/add` into chat to spawn a new entity. Then type `/cmd` to 
+choose from a battery of preset test scripts. You can also write your own test scripts and 
+execute them under the "(Custom)" preset.
+
+Statements in a script can be one of the following:
+
+ * wait <time>: <expr>
+   Calls the given ObjectRef method, <expr> after the given delay, <time>
+
+ * now: <expr>
+   Calls the given ObjectRef method, <expr>, immediately
+
+Alternatively, you can call an ObjectRef method directly by typing `/cmd <expr>` into chat.
+
+All test scripts are executed within a sandbox so that most errors can be trapped without 
+crashing Minetest. Several global variables are provided for convenience when testing:
+
+ * `pi` = math.pi,
+ * `inf` = math.huge,
+ * `nan` = 0/0,
+ * `vec` = vector.new,
+ * `home` = {x = 0, y = 5, z = 0}
+ * `none` = {x = 0, y = 0, z = 0}
+ * `rad360` = 2 * math.pi,
+ * `rad180` = math.pi,
+ * `rad90` = math.pi / 2,
+ * `rad60` = math.pi / 3,
+ * `rad45` = math.pi / 4,
+ * `rad30` = math.pi / 6,
+ * `rad20` = math.pi / 9, 
+
+If you have spawned multiple entities, then you can select which entity to monitor and 
+control either by punching it or typing `/sel` and the respective object ID. To despawn an 
+entity, simply select it and type `/cmd remove()`.
+
+
+Source Code License
+----------------------
+
+GNU Lesser General Public License v3 (LGPL-3.0)
+
+Copyright (c) 2020, Leslie E. Krause
+
+This program is free software; you can redistribute it and/or modify it under the terms of
+the GNU Lesser General Public License as published by the Free Software Foundation; either
+version 3 of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU Lesser General Public License for more details.
+
+http://www.gnu.org/licenses/lgpl-2.1.html
+
+
+Multimedia License (textures, sounds, and models)
+----------------------------------------------------------
+
+Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
+
+   /models/reindeer.b3d
+   by GreenDimond
+   obtained from https://forum.minetest.net/viewtopic.php?t=18958
+
+   /models/paniki.b3d
+   by Lean Rada
+   obtained from https://forum.minetest.net/viewtopic.php?f=50&t=11030
+
+   /textures/mobs_reindeer.png
+   by GreenDimond
+   obtained from https://forum.minetest.net/viewtopic.php?t=18958
+
+   /textures/mobs_paniki.png
+   by Lean Rada
+   obtained from https://forum.minetest.net/viewtopic.php?f=50&t=11030
+
+You are free to:
+Share — copy and redistribute the material in any medium or format.
+Adapt — remix, transform, and build upon the material for any purpose, even commercially.
+The licensor cannot revoke these freedoms as long as you follow the license terms.
+
+Under the following terms:
+
+Attribution — You must give appropriate credit, provide a link to the license, and
+indicate if changes were made. You may do so in any reasonable manner, but not in any way
+that suggests the licensor endorses you or your use.
+
+No additional restrictions — You may not apply legal terms or technological measures that
+legally restrict others from doing anything the license permits.
+
+Notices:
+
+You do not have to comply with the license for elements of the material in the public
+domain or where your use is permitted by an applicable exception or limitation.
+No warranties are given. The license may not give you all of the permissions necessary
+for your intended use. For example, other rights such as publicity, privacy, or moral
+rights may limit how you use the material.
+
+For more details:
+http://creativecommons.org/licenses/by-sa/3.0/
diff --git a/init.lua b/init.lua
new file mode 100644
index 0000000..b6fb4a9
--- /dev/null
+++ b/init.lua
@@ -0,0 +1,530 @@
+-- NB: This mod is intended for use with the Minimal game and expects
+-- a singlenode mapgen. See README.txt for licensing information.
+
+local entity_props = {
+	paniki = {
+		collisionbox = { -0.4, -0.2, -0.4, 0.4, 0.3, 0.4 },
+		textures = { "mobs_paniki.png" },
+		mesh = "paniki.b3d",
+		yaw_origin = -math.pi / 2,
+		enable_swimming = false,
+		enable_climbing = false,
+	},
+	reindeer = {
+		collisionbox = { -0.3, -0.1, -0.3, 0.3, 1.4, 0.3 },
+		textures = { "mobs_reindeer.png" },
+		mesh = "reindeer.b3d",
+		yaw_origin = 0,
+		enable_swimming = true,
+		enable_climbing = true,
+	},
+}
+
+local presets = {
+	["(Custom)"] = { },
+	["(Reset)"] = {
+		"now: set_pos(home)",
+		"now: unlock_velocity()",
+		"now: set_velocity(none)",
+		"now: set_rotation(none)",
+		"now: set_acceleration(none)",
+	},
+	["Big square fly"] = {
+		"now: set_pos(vec(8,5,8))",
+		"now: set_yaw(rad90)",
+		"now: set_acceleration_vert()",
+		"now: set_speed(4)",
+		"after 4: add_yaw(rad90)",
+		"after 4: add_yaw(rad90)",
+		"after 4: add_yaw(rad90)",
+		"after 4: set_speed(0)",
+	},
+	["Big circle fly"] = {
+		"now: set_pos(vec(0,5,8))",
+		"now: set_yaw(rad90)",
+		"now: set_acceleration_vert()",
+		"now: set_speed(4)",
+		"now: turn_by(rad90,3,4)",
+		"after 12: set_speed(0)",
+	},
+	["Big diamond fly"] = {
+		"now: set_pos(vec(0,5,-8))",
+		"now: set_yaw(-rad45)",
+		"now: set_acceleration_vert()",
+		"now: set_speed(4)",
+		"after 2.8: add_yaw(rad90)",
+		"after 2.8: add_yaw(rad90)",
+		"after 2.8: add_yaw(rad90)",
+		"after 2.8: set_speed(0)",
+	},
+	["Roundabounce"] = {
+		"now: set_pos(vec(0,2,8))",
+		"now: set_yaw(rad90)",
+		"now: set_acceleration_vert(-9)",
+		"now: set_speed(2.5)",
+		"now: turn_by(rad45,1,8)",
+		"now: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_velocity_vert(4)",
+		"after 1: set_speed(0)",
+	},
+	["Zig zaggy fun"] = {
+		"now: set_pos(vec(8,5,5))",
+		"now: set_yaw(rad90)",
+		"now: set_acceleration_vert()",
+		"now: set_speed(4)",
+		"after 4: turn_by(rad180,1)",
+		"after 4.5: turn_by(-rad180,1)",
+		"after 4.5: turn_by(rad180,1)",
+		"after 4.5: turn_by(-rad180,1)",
+		"after 4.5: set_speed(0)",
+	},
+	["Lots of collisions"] = {
+		"now: set_pos(vec(0,5,0))",
+		"now: set_yaw()",
+		"now: set_acceleration_vert(-9)",
+		"now: unlock_velocity()",
+		"after 1: set_velocity_horz(-8,0)",
+		"after 1: set_velocity_horz(8,0)",
+		"after 1: set_velocity_horz(-8,0)",
+		"after 1: set_velocity_horz(0,-8)",
+		"after 2: set_velocity_horz(12,0)",
+		"after 2: set_velocity_horz(-12,12)",
+		"after 2: set_velocity_horz(12,0)",
+		"after 2: set_velocity_horz(-12,-12)",
+		"after 2: set_velocity_horz(12,0)",
+		"after 2: set_velocity_horz(-12,0)",
+	},
+	["Drown in water"] = {
+		"now: set_pos(vec(6,4.5,0))",
+		"now: set_yaw()",
+		"now: set_acceleration_vert()",
+		"now: unlock_velocity()",
+		"now: set_velocity(vec(0,-0.2,0))",
+		"after 15: set_velocity_vert(0.2)",
+		"after 1.5: set_velocity_vert(-0.2)",
+		"after 3: set_velocity_vert(0.2)",
+		"after 15: set_velocity_vert()",
+	},
+	["Back and forth"] = {
+		"now: set_pos(vec(-8,2,4))",
+		"now: set_yaw(rad90)",
+		"now: set_acceleration_vert(-9)",
+		"now: set_speed_lateral(0,-2.5)",
+		"after 2: turn_by(rad90,2)",
+		"after 2: set_speed(0)",
+		"after 1.5: set_speed(4)",
+		"after 3.5: set_speed(0)",
+		"after 1.5: set_speed(-2.5)",
+		"now: turn_by(-rad90,2)",
+		"after 4: set_speed(0)",
+	}
+}
+
+local preset_list = { "(Custom)", "(Reset)", "Big square fly", "Big circle fly", "Big diamond fly", "Roundabounce", "Zig zaggy fun", "Lots of collisions", "Drown in water", "Back and forth" }
+
+local is_running = false
+local is_lagging = false
+local player = nil
+local avatar = nil
+local player_huds = nil
+local script = nil
+
+-------------------------------------
+
+local pi = math.pi
+local format = string.format
+local fs = minetest.formspec_escape
+
+local _ = nil
+
+local function is_match( text, glob )
+     -- use underscore variable to preserve captures
+     _ = { string.match( text, glob ) }
+     return #_ > 0
+end
+
+local function printf( ... )
+	minetest.chat_send_all( string.format( ... ) )
+end
+
+local function pos_to_str( vec, is_int )
+	return format( is_int and "(%d,%d,%d)" or "(%0.1f,%0.1f,%0.1f)", vec.x, vec.y, vec.z )
+end
+
+local function rot_to_str( vec )
+	return format( "(%0.1f,%0.1f,%0.1f)", vec.x / pi * 180, vec.y / pi * 180, vec.z / pi * 180 )
+end
+
+local function join( list, sep, func )
+	local str = ""
+	for i, v in ipairs( list ) do
+		local res = func( i, v )
+		if res ~= nil then
+			str = i > 1 and str .. sep .. res or str .. res
+		end
+	end
+	return str
+end
+
+local function sanitize( buf )
+	return string.trim( string.gsub( buf, ".", { ["\r"] = "\n", ["\t"] = " ", ["\f"] = " ", ["\b"] = " " } ) ) .. "\n"
+end
+
+local function update_hud( idx, ... )
+	player:hud_change( player_huds[ idx ], "text", format( ... ) )
+end
+
+local function create_hud( )
+	player_huds = {
+		-- hud background
+		player:hud_add( {
+			hud_elem_type = "image",
+       			text = "default_cloud.png^[colorize:#000066BB",
+	       		scale = { x = -15, y = -31 },
+			position = { x = 0.05, y = 0.25 },
+			alignment = { x = 1, y = 1 },
+		} ),
+		player:hud_add( {
+			hud_elem_type = "image",
+			text = "default_cloud.png^[colorize:#006600BB",
+	       		scale = { x = -15, y = -38 },
+			position = { x = 0.05, y = 0.56 },
+			alignment = { x = 1, y = 1 },
+		} ),
+		player:hud_add( {
+			hud_elem_type = "image",
+			text = "default_cloud.png^[colorize:#006666BB",
+	       		scale = { x = -40, y = -15 },
+			position = { x = 0.30, y = 0.70 },
+			alignment = { x = 1, y = 1 },
+		} ),
+
+		-- hud foreground
+		player:hud_add( {
+			-- pos, rot, new_vel, old_vel
+			hud_elem_type = "text",
+			text = "",
+			position = { x = 0.05, y = 0.25 },
+			scale = { x = -15, y = -31 },
+			number = 0xFFFFFF,
+			alignment = { x = 1, y = 1 },
+			offset = { x = 8, y = 8 }
+		} ),
+		player:hud_add( {
+			-- collides_xz, collides_y, is_standing, is_swimming, is_climbing
+			hud_elem_type = "text",
+			text = "",
+			position = { x = 0.05, y = 0.56 },
+			scale = { x = -15, y = -38 },
+			number = 0xFFFFFF,
+			alignment = { x = 1, y = 1 },
+			offset = { x = 8, y = 8 }
+		} ),
+		player:hud_add( {
+			-- touched_objects
+			hud_elem_type = "text",
+			text = "",
+			position = { x = 0.30, y = 0.70 },
+			scale = { x = -15, y = -15 },
+			number = 0xFFFFFF,
+			alignment = { x = 1, y = 1 },
+			offset = { x = 8, y = 8 }
+		} ),
+		player:hud_add( {
+			-- collisions
+			hud_elem_type = "text",
+			text = "",
+			position = { x = 0.50, y = 0.70 },
+			scale = { x = -15, y = -15 },
+			number = 0xFFFFFF,
+			alignment = { x = 1, y = 1 },
+			offset = { x = 0, y = 8 }
+		} ),
+	}
+end
+
+local function get_formspec( preset_name )
+	local script = presets[ preset_name ]
+	local formspec = "size[10.0,8.0]" ..
+		"real_coordinates[true]" ..
+		format( "textarea[0.5,0.8;9.0,5.8;script;Enter a script for this object:;%s]",
+			join( script, "\n", function ( i, v ) return fs( v ) end ) ) ..
+		"button_exit[7.5,6.9;2.0,0.7;run;Run]" ..
+		"label[0.5,7.2;Preset:]" ..
+		format( "dropdown[1.8,6.9;5.0,0.7;presets;%s;%d",
+			join( preset_list, ",", function ( i, v ) return fs( v ) end ),
+			table.indexof( preset_list, preset_name ) )
+
+	return formspec
+end
+
+local function execute( expr )
+	local func = loadstring( "return obj:" .. expr )
+	if func then
+      		setfenv( func, {
+			obj = avatar,
+			pi = math.pi,
+			inf = math.huge,
+			nan = 0/0,
+			vec = vector.new,
+			home = { x = 0, y = 5, z = 0 },
+			none = { x = 0, y = 0, z = 0 },
+			rad360 = 2 * pi,
+			rad180 = pi,
+			rad90 = pi / 2,
+			rad60 = pi / 3,
+			rad45 = pi / 4,
+			rad30 = pi / 6,
+			rad20 = pi / 9,
+		} )
+		local status, err = pcall( func )
+		if not status then
+			minetest.chat_send_all( "[Avatar] Execution failed: " .. err )
+			return false
+		end
+		if err then
+			minetest.chat_send_all( "[Avatar] Result: " .. tostring( err ) )
+		end
+		return true
+	else
+		minetest.chat_send_all( "[Avatar] Syntax error in expression." )
+		return false
+	end
+end
+
+local function execute_script( script )
+	presets[ "(Custom)" ] = script   -- save script to presets
+
+	local lines = { }
+
+	for i, v in ipairs( script ) do
+		local expr
+		if is_match( v, "^now: (.+)" ) then
+			table.insert( lines, { expr = _[ 1 ] } )
+		elseif is_match( v, "^after (%d+): (.+)" ) or is_match( v, "^after (%d+%.%d): (.+)" ) then
+			table.insert( lines, { time = tonumber( _[ 1 ] ), expr = _[ 2 ] } )
+		else
+			minetest.chat_send_all( format( "[Avatar] Invalid statement on line %d.", i ) )
+			return
+		end
+	end
+
+	local function next_step( idx )
+		while lines[ idx ] do
+			local cur_line = lines[ idx ]
+			if cur_line.time then
+				minetest.after( cur_line.time, function ( )
+					cur_line.time = nil
+					next_step( idx )
+				end )
+				return
+			else
+				minetest.chat_send_all( format( "[Avatar] Line %d: %s", idx, cur_line.expr ) )
+				if not execute( cur_line.expr ) then
+					is_running = false
+					return
+				end
+			end
+			idx = idx + 1
+		end
+		is_running = false
+		minetest.chat_send_all( "[Avatar] Script completed." )
+	end
+
+	is_running = true
+	next_step( 1 )
+end
+
+-------------------------------------
+
+minetest.register_entity( "extend_entity:avatar",{
+	hp_max = 1,
+	physical = true,
+	static_save = true,
+	description = "Avatar",
+	collisionbox = { -0.2, -0.2, -0.2, 0.2, 1.2, 0.2 },
+	visual = "mesh",
+	visual_size = { x = 1, y = 1 },
+	collide_with_objects = true,
+	collision_checks = { },
+	immersion_checks = { "default:water" },
+
+	on_step = function( self, dtime, pos, rot, new_vel, old_vel, res )
+		local obj = self.object
+
+		if avatar == obj then
+			if is_lagging then
+				if math.random( 10 ) == 1 then
+					-- Stall process for 0.3 secs
+					local t = os.clock( )
+					while os.clock( ) - t <= 0.3 do end
+				end
+			end
+
+			update_hud( 4, "pos:\n%s\n\nrot:\n%s\n\nnew_vel:\n%s\n\nold_vel:\n%s",
+				pos_to_str( pos ), rot_to_str( rot ), pos_to_str( new_vel ), pos_to_str( old_vel ) )
+			update_hud( 5, "is_standing:\n%s\n\nis_swimming:\n%s\n\nis_climbing:\n%s\n\ncollides_xz\n%s\n\ncollides_y\n%s",
+				tostring( res.is_standing ), tostring( res.is_swimming ), tostring( res.is_climbing ),
+				tostring( res.collides_xz ), tostring( res.collides_y ) )
+			update_hud( 6, "touched_objects:\n%s", join( res.touched_objects, "\n", function ( i, v )
+					return ( v and "player" or "entity" ) .. " @ " .. pos_to_str( v:get_pos( ) )
+				end ) )
+			update_hud( 7, "collisions:\n%s", join( res.collisions, "\n", function ( i, v )
+					return minetest.get_node( v ).name .. " @ " .. pos_to_str( v, true )
+				end ) )
+		end
+
+		print( string.format( "[%d] pos=%s rot=%s new_vel=%s old_vel=%s, col_xz=%s, col_y=%s",
+			self.id, pos_to_str( pos ), rot_to_str( rot ), pos_to_str( new_vel ), pos_to_str( old_vel ),
+			tostring( res.collides_xz ), tostring( res.collides_y ) ) )
+	end,
+
+	on_activate = function ( self, staticdata, dtime, id )
+		printf( "[Avatar] on_activate( ): dtime=%0.1f, id=%d", dtime, id )
+		self.id = id
+	end,
+
+	on_deactivate = function ( self, id )
+		printf( "[Avatar] on_deactivate( ): id=%d", id )
+		if avatar == self.object then
+			for i, v in ipairs( player_huds ) do
+				player:hud_remove( v )
+				player_huds = nil
+			end
+			avatar = nil
+			printf( "[Avatar] Deselected object id " .. self.id .. "." )
+		end
+	end,
+
+	on_punch = function ( self )
+		avatar = self.object
+		printf( "[Avatar] Selected object id " .. self.id .. "." )
+	end,
+
+	get_staticdata = function ( self )
+		printf( "[Avatar] get_staticdata( )" )
+	end,
+} )
+
+minetest.register_chatcommand( "add", {
+	func = function( name, param )
+		player = minetest.get_player_by_name( name )
+		avatar = minetest.add_entity( { x = 0, y = 5, z = 0 }, "extend_entity:avatar" )
+
+		avatar:set_properties( entity_props[ param ] or entity_props.reindeer )
+		if not player_huds then
+			create_hud( )
+		end
+
+		return true, "[Avatar] Selected object id " .. avatar:get_luaentity( ).id .. "."
+	end
+} )
+
+minetest.register_chatcommand( "sel", {
+	func = function( name, param )
+		local id = tonumber( param )
+		if minetest.luaentities[ id ] then
+			avatar = minetest.luaentities[ id ].object
+			if not player_huds then
+				create_hud( )
+			end
+
+			return true, "[Avatar] Selected object id " .. id .. "."
+		end
+	end
+} )
+
+minetest.register_chatcommand( "cmd", {
+	func = function( name, param )
+		if avatar then
+			if is_running then
+				return false, "[Avatar] The script is still running."
+			elseif param == "" then
+				minetest.show_formspec( name, "extend_entity:editor", get_formspec( preset_list[ 1 ] ) )
+				return true
+			else
+				return execute( param )
+			end
+		else
+			return false, "[Avatar] No object selected."
+		end
+	end
+} )
+
+minetest.register_chatcommand( "lag", {
+	func = function( name, param )
+		is_lagging = not is_lagging
+		return true, "[Avatar] Randomly induced lag " .. ( is_lagging and "enabled" or "disabled" ) .. "."
+	end
+} )
+
+minetest.register_on_player_receive_fields( function( player, formname, fields )
+        local name = player:get_player_name( )
+
+        if formname ~= "extend_entity:editor" then return end
+
+	if fields.run then
+		execute_script( string.split( sanitize( fields.script ), "\n" ) )
+	elseif fields.presets then
+		local idx = table.indexof( preset_list, fields.presets )
+		minetest.show_formspec( name, "extend_entity:editor", get_formspec( preset_list[ idx ] ) )
+	end
+end )
+
+local function construct_spawn( )
+	for y = 0, 4 do
+		for x = -20 - y, 20 + y do
+			for z = -20 - y, 20 + y do
+				minetest.set_node( { x = x, y = 1 - y, z = z}, { name = "default:cobble" } )
+			end
+		end
+	end
+
+	for y = 2, 5 do
+		for x = -10, 10 do
+			minetest.set_node( { x = x, y = y, z = -10 }, { name = "default:cobble" } )
+			minetest.set_node( { x = x, y = y, z = 10 }, { name = "default:cobble" } )
+		end
+		for z = -9, 9 do
+			minetest.set_node( { x = -10, y = y, z = -z }, {name = "default:cobble" } )
+			minetest.set_node( { x = 10, y = y, z = z }, { name = "default:cobble" } )
+		end
+		minetest.set_node( { x = 0, y = y, z = 9 }, { name = "default:ladder", param2 = 4 } )
+	end
+
+	for y = 2, 3 do
+		for z = -2, 2 do
+			for x = 4, 8 do
+				local is_cobble = math.abs( z ) == 2 or x % 4 == 0
+				minetest.set_node( { x = x, y = y, z = z }, {
+					name = is_cobble and "default:cobble" or "default:water_source"
+				} )
+
+				minetest.set_node( { x = -x, y = y, z = z }, {
+					name = is_cobble and "default:cobble" or "default:lava_source"
+				} )
+			end
+		end
+	end
+
+	for x = -2, 2 do
+		minetest.set_node( { x = x, y = 2, z = 0 }, { name = "default:ladder", param2 = 1 } )
+	end
+end
+
+minetest.register_on_joinplayer( function( )
+	minetest.after( 0.5, construct_spawn )
+end )
+
+minetest.register_on_leaveplayer( function ( )
+	if avatar then
+		avatar_obj:remove( )
+	end
+end )
+
diff --git a/models/paniki.b3d b/models/paniki.b3d
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diff --git a/models/reindeer.b3d b/models/reindeer.b3d
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diff --git a/textures/mobs_paniki.png b/textures/mobs_paniki.png
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diff --git a/textures/mobs_reindeer.png b/textures/mobs_reindeer.png
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