Build 04

- minor code reorganization
- renamed 'class' to 'propagator' for consistency
- added compatibility layer for Minetest S3 engine
- implemented emission propagator with example code
- updated README.txt with dependency information

README.txt

@@ -10,6 +10,17 @@ For complete usage instructions, please refer to the forum topic:
 https://forum.minetest.net/viewtopic.php?f=9&t=24721
 
 
+Compatability
+----------------------
+
+Requires PR #9717 for Minetest 5.3-dev
+
+Dependencies
+----------------------
+
+Mobs Lite Mod (required)
+  https://bitbucket.org/sorcerykid/mobs
+  
 Repository
 ----------------------
 

compatibility.lua

@@ -0,0 +1,27 @@
+minetest.count_nodes_in_area = function( pos_min, pos_max, names, is_group )
+	local counts, node_counts
+	local voxel_manip = minetest.get_voxel_manip( )
+
+	voxel_manip:read_from_map( pos_min, pos_max )
+	node_counts = select( 2, minetest.find_nodes_in_area( pos_min, pos_max, names ) )
+
+	if is_group == false then
+		return counts
+	end
+
+	counts = { }    -- use new table for transposing node counts into group counts
+	for _, name in ipairs( names ) do
+		local group_name = string.match( name, "group:(.+)" )
+		if group_name then
+			counts[ name ] = 0
+			for node_name, node_count in pairs( node_counts ) do
+				if minetest.registered_nodes[ node_name ].groups[ group_name ] then
+					counts[ name ] = counts[ name ] + node_count
+				end
+			end
+		else
+			counts[ name ] = node_counts[ name ]
+		end
+	end
+	return counts
+end

depends.txt

@@ -0,0 +1,3 @@
+default
+fire
+mobs

init.lua

@@ -19,6 +19,7 @@ local stack_size = 0
 local random = math.random
 local pow = math.pow
 local ceil = math.ceil
+local min = math.min
 
 local function check_limits( v, min_v, max_v )
 	return v >= min_v and v <= max_v
@@ -28,18 +29,8 @@ local function clamp( val, min, max )
 	return val < min and min or val > max and max or val
 end
 
-local function get_power_decrease( scale, power, ratio )
-	return ratio <= 1 - scale and 1.0 or
-		max( 1 - pow( ( scale + ratio - 1 ) / scale, 1 + power ), 0 )
-end
-
-local function get_power_increase( scale, power, ratio )
-	return ratio >= scale and 1.0 or
-		1 - pow( ( scale - ratio ) / scale, 1 + power )
-end
-
 local function get_signal_strength( max_value, cur_value, slope )
-	return math.pow( cur_value / max_value, 1 - clamp( slope, 0, 1 ) )
+	return pow( cur_value / max_value, 1 - clamp( slope, 0, 1 ) )
 end
 
 local function punch_object( obj, groups, pos )
@@ -60,7 +51,7 @@ local function ContactStimulus( node_name, group, intensity, chance, period, pow
 	local self = { }
 
 	self.group = group
-	self.class = "contact"
+	self.propagator = "contact"
 	self.period = period
 
 	self.on_action = function ( source_pos, target_obj )
@@ -82,37 +73,11 @@ local function ContactStimulus( node_name, group, intensity, chance, period, pow
 	return self
 end
 
-local function RadiationStimulus( node_name, group, intensity, chance, period, radius, scale, power, max_count )
-	local self = { }
-
-	self.group = group
-	self.class = "radiation"
-	self.period = period
-
-	self.on_action = function ( source_pos, target_obj )
-		if random( chance ) == 1 then
-			local touch_counts = minetest.count_nodes_in_area(
-				vector.add( source_pos, -radius ), vector.add( source_pos, radius ), { node_name }, true )
-			local count = touch_counts[ node_name ]
-
-			if count > 0 then
-				local damage = intensity * get_power_increase( scale, power, count / max_count )
-				target_obj:punch( target_obj, period, {
-					full_punch_interval = period,
-					damage_groups = { [group] = damage },
-	     			}, nil )
-			end
-		end
-	end
-
-	return self
-end
-
 local function ImmersionStimulus( node_name, group, intensity, chance, period )
 	local self = { }
 
 	self.group = group
-	self.class = "immersion"
+	self.method = "immersion"
 	self.period = period
 
 	self.on_action = function ( source_pos, target_obj )
@@ -132,6 +97,59 @@ local function ImmersionStimulus( node_name, group, intensity, chance, period )
 	return self
 end
 
+local function RadiationStimulus( node_name, group, intensity, chance, period, radius, power )
+	local self = { }
+
+	self.group = group
+	self.propagator = "radiation"
+	self.period = period
+
+	self.on_action = function ( source_pos, target_obj )
+		if random( chance ) == 1 then
+			local touch_counts = minetest.count_nodes_in_area(
+				vector.add( source_pos, -radius ), vector.add( source_pos, radius ), { node_name }, true )
+			local count = touch_counts[ node_name ]
+
+			if count > 0 then
+				local damage = intensity * pow( count, power )
+				target_obj:punch( target_obj, period, {
+					full_punch_interval = period,
+					damage_groups = { [group] = damage },
+	     			}, nil )
+			end
+		end
+	end
+
+	return self
+end
+
+local function EmissionStimulus( node_name, group, intensity, chance, period, radius, slope )
+	local self = { }
+
+	self.group = group
+	self.propagator = "radiation"
+	self.period = period
+
+	self.on_action = function ( source_pos, target_obj )
+		if random( chance ) == 1 then
+			-- get nearest node position in a radius, including the center
+			local node_pos = minetest.find_node_near( source_pos, radius, { node_name }, true )
+
+			if node_pos then
+				local length = min( radius, vector.distance( node_pos, source_pos ) )
+				local damage = ceil( intensity * get_signal_strength( radius, radius - length, slope ) )
+
+				target_obj:punch( target_obj, period, {
+					full_punch_interval = period,
+					damage_groups = { [group] = damage },
+	     			}, nil )
+			end
+		end
+	end
+
+	return self
+end
+
 local function AxonPropagator( obj )
 	local event_defs = { }
 	local clock = 0.0
@@ -252,12 +270,16 @@ axon.register_source = function ( node_name, stimulus_list )
 	end
 	for i, v in pairs( stimulus_list ) do
 		local stimulus
-		if v.class == "contact" then
+		if v.propagator == "contact" then
 			stimulus = ContactStimulus( node_name, v.group, v.intensity, v.chance, v.period, v.power )
-		elseif v.class == "radiation" then
+		elseif v.propagator == "immersion" then
-			stimulus = RadiationStimulus( node_name, v.group, v.intensity, v.chance, v.period, v.radius, v.scale, v.power, v.max_count )
-		elseif v.class == "immersion" then
 			stimulus = ImmersionStimulus( node_name, v.group, v.intensity, v.chance, v.period )
+		elseif v.propagator == "radiation" then
+			stimulus = RadiationStimulus( node_name, v.group, v.intensity, v.chance, v.period, v.radius, v.power )
+		elseif v.propagator == "emission" then
+			stimulus = EmissionStimulus( node_name, v.group, v.intensity, v.chance, v.period, v.radius, v.slope )
+		else
+			error( "axon.register_source(): Unknown propagator specified in stimulus property table" )
 		end
 		table.insert( sources[ node_name ], stimulus )
 	end
@@ -276,11 +298,11 @@ axon.generate_direct_stimulus = function ( obj, groups )
 	punch_object( obj, groups )
 end
 
-axon.generate_radial_stimulus = function ( pos, radius, speed, slope, chance, groups, classes )
+axon.generate_radial_stimulus = function ( pos, radius, speed, slope, groups, classes )
 	for obj in mobs.iterate_registry( pos, radius, radius, classes ) do
 		local length = vector.distance( pos, obj:get_pos( ) )
 
-		if length <= radius and random( chance ) == 1 then
+		if length <= radius then
 			local damage_groups = { }
 
 			for k, v in pairs( groups ) do
@@ -301,3 +323,10 @@ end
 --------------------
 
 dofile( minetest.get_modpath( "axon" ) .. "/sources.lua" )
+
+-- compatibility for Minetest S3 engine
+
+if not minetest.count_nodes_in_area then
+        dofile( minetest.get_modpath( "axon" ) .. "/compatibility.lua" )
+end
+

sources.lua

@@ -1,16 +1,16 @@
 -- This is a sample source definition file. You will want to modify this for your particular game.
 
 axon.register_source( "group:lava_source", {
-	{ group = "heat_stim", class = "radiation", intensity = 30, chance = 1, period = 1.5, radius = 5.0, scale = 1.0, power = 0.0, max_count = 6 },
+	{ group = "heat_stim", propagator = "radiation", intensity = 10, chance = 1, period = 1.5, radius = 5.0, power = 0.3 },
-	{ group = "lava_stim", class = "immersion", intensity = 10, chance = 1, period = 0.5 },
+	{ group = "lava_stim", propagator = "immersion", intensity = 10, chance = 1, period = 0.5 },
 } )
 
 axon.register_source( "group:water_source", {
-	{ group = "water_stim", class = "immersion", intensity = 5, chance = 1, period = 0.5 },
+	{ group = "water_stim", propagator = "immersion", intensity = 10, chance = 1, period = 0.5 },
 } )
 
 axon.register_source( "group:heat_source", {
-	{ group = "heat_stim", class = "contact", intensity = 3, chance = 2, period = 1.0, power = 0.8 },
+	{ group = "heat_stim", propagator = "contact", intensity = 3, chance = 2, period = 1.0, power = 0.8 },
 } )
 
 axon.register_source_group( "lava_source", { "default:lava_source", "default:lava_flowing" } )