Chasms (#19)

* initial chasms mod

* tweak default chasm settings

* prevent chasms from breaching oil and magma seas, make veinstone actually do something

* overgenerate caverns to eliminate floating stalactites

* make veinstone punchable instead of right-clickable

* ensure dfcaverns get carved before chasms

this has an unfortunate tradeoff. Chasms will no longer have floating giant columns in them, but will also no longer have smaller stalactites and stalagmites. Also will carve chasms through lake water. Not sure if this is ideal.

* add rare big webs to the chasms, to give them a unique feature

* reverse the dependencies for df_caverns and chasms, let chasms go first.

* fix web generator

* add webs to level 3 tunnels, fix sunless sea chasms

* fix up tunnel webs

* make webs snappy

* make webs slightly more prevalent

* add chasms to the guide

* final touch-ups before merging

* allow anchoring against unloaded blocks

big_webs/LICENSE.txt

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+Sounds and textures are under various licenses, see the license.txt file in the /sounds and /textures directories for details.
+
+License for Code
+----------------
+
+Copyright (C) 2021 FaceDeer
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

big_webs/init.lua

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+local modname = minetest.get_current_modname()
+local S = minetest.get_translator(modname)
+
+local default_path = minetest.get_modpath("default")
+
+local get_node_box = function(connector_thickness)
+	return {
+		type = "connected",
+		--fixed = {-hub_thickness,-hub_thickness,-hub_thickness,hub_thickness,hub_thickness,hub_thickness},
+		connect_top = {-connector_thickness, 0, -connector_thickness, connector_thickness, 0.5, connector_thickness},
+		connect_bottom = {-connector_thickness, -0.5, -connector_thickness, connector_thickness, 0, connector_thickness},
+		connect_back = {-connector_thickness, -connector_thickness, 0, connector_thickness, connector_thickness, 0.5},
+		connect_right = {0, -connector_thickness, -connector_thickness, 0.5, connector_thickness, connector_thickness},
+		connect_front = {-connector_thickness, -connector_thickness, -0.5, connector_thickness, connector_thickness, 0},
+		connect_left = {-0.5, -connector_thickness, -connector_thickness, 0, connector_thickness, connector_thickness},
+		disconnected = {-connector_thickness, -connector_thickness, -connector_thickness, connector_thickness, connector_thickness, connector_thickness},
+	}
+end
+
+local in_anchor_group = function(name)
+	return
+		minetest.get_item_group(name, "soil") > 0 or
+		minetest.get_item_group(name, "stone") > 0 or
+		minetest.get_item_group(name, "tree") > 0 or
+		minetest.get_item_group(name, "leaves") > 0 or
+		minetest.get_item_group(name, "sand") > 0 or
+		minetest.get_item_group(name, "wood") > 0 or
+		name == "ignore"
+end
+
+local cardinal_directions = {
+	{x=1,y=0,z=0},
+	{x=-1,y=0,z=0},
+	{x=0,y=1,z=0},
+	{x=0,y=-1,z=0},
+	{x=0,y=0,z=1},
+	{x=0,y=0,z=-1}
+}
+
+local cardinal_planes = {
+	{3,5},
+	{3,5},
+	{1,5},
+	{1,5},
+	{1,3},
+	{1,3},
+}
+
+local insert_if_not_in_hashtable = function(pos, insert_into, if_not_in)
+	local hash = minetest.hash_node_position(pos)
+	if if_not_in[hash] then
+		return
+	end
+	table.insert(insert_into, pos)
+end
+
+-- flood fill through the web to get all web and anchor locations
+local get_web_nodes = function(pos, webs, anchors)
+	local to_check = {}
+	table.insert(to_check, pos)
+	while next(to_check) ~= nil do
+		local check_pos = table.remove(to_check)
+		local check_node = minetest.get_node(check_pos)
+		if minetest.get_item_group(check_node.name, "webbing") > 0 then
+			webs[minetest.hash_node_position(check_pos)] = true
+			for _, dir in pairs(cardinal_directions) do
+				insert_if_not_in_hashtable(vector.add(check_pos, dir), to_check, webs)
+			end
+		elseif in_anchor_group(check_node.name) then
+			anchors[minetest.hash_node_position(check_pos)] = true
+		end		
+	end	
+end
+
+local sound
+if default_path then
+	sound = default.node_sound_leaves_defaults()
+end
+
+
+local web_line = function(pos, dir, distance)
+	local web_spine = {}
+	for i = 0, distance do
+		local web_pos = vector.add(pos, vector.multiply(dir,i))
+		local node_name = minetest.get_node(web_pos).name
+		if node_name == "air" or node_name == "big_webs:webbing" then
+			table.insert(web_spine, web_pos)
+		elseif in_anchor_group(node_name) then
+			anchored=true
+			break
+		else
+			anchored=false
+			break
+		end
+	end
+
+	if anchored then
+		for _, web_pos in pairs(web_spine) do
+			if math.random() < 0.9 then
+				minetest.set_node(web_pos, {name="big_webs:webbing"})
+			end
+		end
+		return web_spine
+	end
+	return nil
+end
+
+local generate_web = function(pos)
+	local dir_choice = math.random(1, 6)
+	local dir = cardinal_directions[dir_choice]
+	local web_spine = web_line(pos, dir, 30)
+	if web_spine then
+		local dir2 = cardinal_directions[cardinal_planes[dir_choice][math.random(1, 2)]]
+		local dir2_opposite = vector.multiply(dir2, -1)
+		for _, web_pos in pairs(web_spine) do
+			web_line(web_pos, dir2, 15)
+			web_line(web_pos, dir2_opposite, 15)
+		end
+	end
+end
+
+minetest.register_node("big_webs:webbing", {
+	description = S("Giant Cave Spider Webbing"),
+	_doc_items_longdesc = S("Thick ropes of sticky, springy silk, strung between cavern walls in hopes of catching bats and even larger beasts."),
+	_doc_items_usagehelp = S("Webbing can be collected and re-strung elsewhere to aid in climbing. It absorbs all falling damage when you land on it."),
+	tiles = {
+		{name="big_webs.png"},
+	},
+	use_texture_alpha = "blend",
+    connects_to = {"group:soil", "group:stone", "group:tree", "group:leaves", "group:sand", "group:wood", "group:webbing"},
+    connect_sides = { "top", "bottom", "front", "left", "back", "right" },
+	drawtype = "nodebox",
+	node_box = get_node_box(0.0625),
+	collision_box = get_node_box(0.0625),
+	inventory_image = "big_webs_item.png",
+	wield_image = "big_webs_item.png",
+	paramtype = "light",
+	is_ground_content = false,
+	climbable = true,
+	floodable = true,
+	groups = {snappy = 2, choppy = 2, webbing = 1, flammable=1, fall_damage_add_percent=-100, bouncy=20},
+	sounds = sound,
+	on_construct = function(pos)
+		minetest.get_node_timer(pos):start(30)
+	end,
+	on_destruct = function(pos)
+		for _, dir in pairs(cardinal_directions) do
+			local neighbor_pos = vector.add(pos, dir)
+			if minetest.get_item_group(minetest.get_node(neighbor_pos).name, "webbing") > 0 then
+				minetest.get_node_timer(neighbor_pos):start(30)
+			end
+		end
+		minetest.get_node_timer(pos):stop()
+	end,
+	on_timer = function(pos, elapsed)
+		local webs = {}
+		local anchors = {}
+		get_web_nodes(pos, webs, anchors)
+		local first_anchor = next(anchors)
+		for hash, _ in pairs(webs) do
+			local web_pos = minetest.get_position_from_hash(hash)
+			if first_anchor == nil then
+				-- unsupported web
+				minetest.set_node(web_pos, {name="air"})
+				minetest.item_drop(ItemStack("big_webs:webbing"), nil, web_pos)
+			end
+			minetest.get_node_timer(web_pos):stop() -- no need to recheck
+		end	
+	end,
+})
+
+minetest.register_node("big_webs:web_egg", {
+	description = S("Giant Cave Spider Web Generator"),
+	tiles = {
+		{name="big_webs.png"},
+	},
+	use_texture_alpha = "blend",
+    connects_to = {"group:soil", "group:stone", "group:tree", "group:leaves", "group:sand", "group:wood", "group:webbing"},
+    connect_sides = { "top", "bottom", "front", "left", "back", "right" },
+	drawtype = "nodebox",
+	node_box = get_node_box(0.0625),
+	collision_box = get_node_box(0.0625),
+	inventory_image = "big_webs_item.png",
+	wield_image = "big_webs_item.png",
+	paramtype = "light",
+	is_ground_content = false,
+	climbable = true,
+	floodable = true,
+	groups = {snappy = 2, choppy = 2, webbing = 1, flammable=1, fall_damage_add_percent=-100, bouncy=20},
+	sounds = sound,
+	on_construct = function(pos)
+		minetest.get_node_timer(pos):start(1)
+	end,
+	on_timer = function(pos, elapsed)
+		minetest.set_node(pos, {name="air"})
+		generate_web(pos)
+	end,
+})

big_webs/locale/template.txt

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+# textdomain: big_webs
+
+
+### init.lua ###
+
+Giant Cave Spider Web Generator=
+Giant Cave Spider Webbing=
+
+Thick ropes of sticky, springy silk, strung between cavern walls in hopes of catching bats and even larger beasts.=
+
+Webbing can be collected and re-strung elsewhere to aid in climbing. It absorbs all falling damage when you land on it.=
+

big_webs/mod.conf

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+name=big_webs
+optional_depends=default