init.lua

--[[
Mod for Luanti that adds bridges (only one node wide!), slim handrails and a self-building-one-node-wide bridge.

    Copyright (C) 2013 Sokomine

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
--]]

-- to make life a bit easier
local bild_pfad = core.get_modpath("default") and "default_wood.png" or "[combine:16x16^[noalpha^[colorize:#654321";
local bild_pfad_s1 = bild_pfad;
local bild_pfad_s2 = bild_pfad;

local leg_front_left     = {-0.5,-0.5,-0.5, -0.4,0.5,-0.4};
local leg_front_right    = { 0.4,-0.5,-0.5,  0.5,0.5,-0.4};
local leg_back_left      = {-0.5,-0.5, 0.4, -0.4,0.5, 0.5};
local leg_back_right     = { 0.4,-0.5, 0.4,  0.5,0.5, 0.5};

local bar_left           = {-0.5, 0.35,-0.4,-0.4, 0.4, 0.4};
local bar_right          = { 0.4, 0.35,-0.4, 0.5, 0.4, 0.4};
local bar_back           = { 0.4, 0.35, 0.4,-0.5, 0.4, 0.5};
local bar_front          = { 0.5, 0.35,-0.5,-0.5, 0.4,-0.4};

local bar_left_long      = {-0.4, 0.35,-0.5,-0.5, 0.4, 0.5};
local bar_right_long     = { 0.4, 0.35,-0.5, 0.5, 0.4, 0.5};

local groundplate_small  = {-0.4,-0.45,-0.5,  0.4,-0.4,0.5};
local groundplate_corner = {-0.5,-0.45,-0.5,  0.5,-0.4,0.5}; -- slightly larger

local STICK = "group:stick";
local WOOD  = "stairs:slab_wood";
local BASIS = "bridges:bridge_basis";
local RAIL  = "bridges:handrail_middle";
-- people who do not have vines have to replace "vines:vines" with something they do have and which they think might fit
local VINES = "vines:vines"; -- useful for ropes
local ALT   = "group:leaves"; -- alternative for vines

if( core.get_modpath( 'moon' ) or core.get_modpath( 'moonrealm') or core.get_modpath( 'moontest') ) then
	STICK = "group:stick";
	WOOD  = "default:steel_ingot";
	VINES = "group:stone";
	ALT   = "group:leaves"; -- alternative for vines

	bild_pfad          = "default_steel_block.png"; --"forniture_wood.png";
	bild_pfad_s1       = bild_pfad; --"forniture_wood_s1.png";
	bild_pfad_s2       = bild_pfad; --"forniture_wood_s2.png";

-- only if no moontest is installed
elseif( core.get_modpath( 'moreblocks' )) then
	WOOD = 'moreblocks:slab_wood';
end

local MAX_BRIDGE_LENGTH = 27; -- this is how far the automatic bridge can extend

local BRIDGE_PARTS = {
    -- name, description, node definition, crafting receipe, additional information for yield of receipe

    -- the groundplate - essential for bridge building
    {
		"bridge_basis",
		"groundplate of a bridge",
		{ groundplate_small },
        {
			{ VINES, VINES, VINES },
            { VINES, WOOD,  VINES },
            { VINES, VINES, VINES }
        },
		" 2"
	}, -- yields 2 groundplates
    -- the handrail is a basic part out of which bridges and handrails for staircases can be constructed
	{
		"handrail_middle",
		"handrail for bridges and staircases",
		{ bar_front },
		{
			{ "", "", "" },
			{ "", BASIS, "" },
			{ "", "", "" }
		},
		" 4"
	}, -- one groundplate yiels 4 handrails

        -- bridges
	{
		"bridge_small",
		"small bridge",
		{ -- TODO: slim legs?
			leg_front_left,
			leg_front_right,
			leg_back_left,
			leg_back_right,
			bar_right,
			bar_left,
			groundplate_small,
		},
		{
			{ STICK, "",    STICK },
			{ RAIL,  BASIS, RAIL  },
			{ STICK, "",    STICK }
		},
		""
	},
	{
		"bridge_middle",
		"middle of a bridge",
		{
			bar_right_long,
			bar_left_long,
			groundplate_small,
		},
		{
			{ "", "", "" },
			{ RAIL, BASIS, RAIL },
			{ "", "", "" }
		},
		""
	},
	{ "bridge_corner", "corner of a bridge", {
		leg_front_left,
		leg_front_right,
		leg_back_left,
		leg_back_right,
		bar_right,
		bar_back,
		groundplate_corner, },
		{ { STICK, RAIL,  STICK },
		{ "",    BASIS, RAIL  },
		{ STICK, "",    STICK }
		}, "" },
	{ "bridge_t",  "T junction of a bridge", {
		leg_front_left,
		leg_front_right,
		leg_back_left,
		leg_back_right,
		bar_back,
		groundplate_corner, },
			{ { STICK, RAIL,  STICK },
			{ "",    BASIS, ""    },
			{ STICK, "",    STICK }
			}, "" },
	{ "bridge_end", "end of a bridge", {
		leg_front_left,
		leg_front_right,
		leg_back_left,
		leg_back_right,
		bar_left,
		bar_right,
		bar_back,
		groundplate_corner, },
		{ { STICK, RAIL,  STICK },
		{ RAIL,  BASIS, RAIL  },
		{ STICK, "",    STICK }
		}, "" },

	-- handrails for the top of starcaises so that people won't fall down
	{ "handrail_top", "handrail for staircases, one side closed", {
		leg_front_left,
		leg_front_right,
		bar_front, },
		{ { "",    "",    ""    },
		{ "",    "",    ""    },
		{ STICK, RAIL,  STICK }
		}, "" },

	{ "handrail_corner", "handrail for staircases, two sides closed", {
		leg_front_left,
		leg_front_right,
		bar_front,
		bar_left },
		{ { STICK, "",    ""    },
		{ RAIL,  "",    ""    },
		{ STICK, RAIL,  STICK }
		}, "" },

	{ "handrail_closed", "handrail for staircases, three sides closed", {
		leg_front_left,
		leg_front_right,
		bar_front,
		bar_right,
		bar_left },
		{ { STICK, RAIL,  STICK },
		{ RAIL,  "",    ""    },
		{ STICK, RAIL,  STICK }
		}, "" },
}


for i in ipairs( BRIDGE_PARTS ) do
	core.register_node("bridges:"..BRIDGE_PARTS[i][1], {
		description = BRIDGE_PARTS[i][2],
		tiles = {
			bild_pfad,
			bild_pfad,
			bild_pfad_s1,
			bild_pfad_s1,
			bild_pfad_s2,
			bild_pfad_s2,
		},
		drawtype = "nodebox",
		sunlight_propagates = true,
		paramtype = 'light',
		paramtype2 = "facedir",
		node_box = {
			type = "fixed",
			fixed = BRIDGE_PARTS[i][3],
		},
		selection_box = {
			type = "fixed",
			fixed = {-0.5,-0.5,-0.5, 0.5, 0.5, 0.5},
		},
		-- flammable so that it can be burned if no longer needed
		groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2,flammable=3},
	});

	core.register_craft({
		output = "bridges:"..BRIDGE_PARTS[i][1]..BRIDGE_PARTS[i][5],
		recipe = BRIDGE_PARTS[i][4],
	});
end

-- alternate receipe for the bridge basis
core.register_craft({
	output = "bridges:bridge_basis 2",
	recipe = {
		{ ALT, ALT, ALT },
		{ ALT, WOOD, ALT },
		{ ALT, ALT, ALT },
	},
});

-- a bridge with covers 3 nodes in size

core.register_node("bridges:bridge_large",
	{ description = 'large bridge',
	tiles = {
		bild_pfad,
		bild_pfad,
		bild_pfad_s1,
		bild_pfad_s1,
		bild_pfad_s2,
		bild_pfad_s2,
	},
	drawtype = "nodebox",
	sunlight_propagates = true,
	paramtype = 'light',
	paramtype2 = "facedir",
	node_box = {
		type = "fixed",
		fixed = {
			-- the large bridge covers 3 nodes
			{-0.5,-0.5,-0.7, -0.4,0.5,-0.6},
			{ 0.4,-0.5,-0.7,  0.5,0.5,-0.6},

			{-0.5, 0.35,-1.5, -0.4,0.4, 1.5},

			{-0.5,-0.5, 0.6, -0.4,0.5, 0.7},
			{ 0.4,-0.5, 0.6,  0.5,0.5, 0.7},

			{ 0.4, 0.35,-1.5,  0.5,0.4, 1.5},

			{-0.4,-0.45,-1.5,  0.4,-0.4,1.5},
		}
	},
	selection_box = {
		type = "fixed",
		fixed = {-0.5,-0.5,-1.5,  0.5,0.5, 1.5},
	},
	groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2,flammable=2}
})

core.register_craft({
	output = "bridges:bridge_large",
	recipe = {
		{ "", "bridges:bridge_middle", "" },
		{ "", "bridges:bridge_small",  "" },
		{ "", "bridges:bridge_middle", "" },
	}
});

-- special: self-building automatic bridge

core.register_node("bridges:bridge_auto", {
	description = "self building bridge",
	-- looks from all sides like the top of a chest
	tiles = {(core.get_modpath("default") and "default_chest_top.png" or "[combine:16x16^[noalpha^[colorize:#654321")},
	drawtype = "cube",
	is_ground_content = true,
	groups = {snappy=2,choppy=2,oddly_breakable_by_hand=2,flammable=3},

	drop = "", -- all leftover parts are in the "chest"

	on_construct = function(pos)
		local meta = core.get_meta(pos);
		meta:set_string("formspec",
						"invsize[8,9;]"..
						"list[current_name;main;0,0;8,4;]"..
						"list[current_player;main;0,5;8,4;]")
		meta:set_string("infotext", "Automatic bridge building set - leftover parts")
		local inv = meta:get_inventory();
		inv:set_size("main", 8*4);
	end,

	can_dig = function(pos,player)
		local meta = core.get_meta(pos);
		local inv = meta:get_inventory();
		return inv:is_empty("main");
	end,

	after_place_node = function(pos, placer)

		local x_dir;
		local z_dir;
		local p;
		local n;

		-- the bridge ought to unfold in the direction the player is looking
		local dir = placer:get_look_dir();
		local fdir = core.dir_to_facedir(dir);

		-- the player is looking more in x- than in z-direction
		if( math.abs( dir.x ) > math.abs( dir.z )) then
		z_dir = 0;
		if( dir.x > 0 ) then
			x_dir = 1;
		else
			x_dir = -1;
		end
		else
		x_dir = 0;
		if( dir.z > 0 ) then
			z_dir = 1;
		else
			z_dir = -1;
		end
		end

--        print ("x_dir: "..tostring( x_dir ).." z_dir: "..tostring( z_dir ));

		-- we have determined the direction in which the bridge may extend - now lets look how far it can go
		local i=1;
		-- how many parts of the bridge remain?
		local rem_small  = math.floor(MAX_BRIDGE_LENGTH/3);
		local rem_middle = MAX_BRIDGE_LENGTH-rem_small;
		-- extend max. MAX_BRIDGE_LENGTH nodes wide and only if the node needs a bridge (i.e. consists of air)
		while( i < MAX_BRIDGE_LENGTH ) do

			-- is there space for a bridge?
			p = {x=pos.x+(x_dir*i), y=pos.y, z=pos.z+(z_dir*i)};
			n = core.get_node(p);
			if( n == nil or
				(n.name ~= "air" and n.name ~= 'moonrealm:vacuum' and n.name ~= 'moonrealm:air'
				and n.name ~= 'moontest:vacuum' and n.name ~= 'moontest:air')
			) then
				i = MAX_BRIDGE_LENGTH+1; -- end
			else
			-- one small bridge is followed by two middle parts
			if( i%3 == 1 ) then
				core.add_node(p, {name="bridges:bridge_small", param1=0, param2=fdir});
				rem_small  = rem_small - 1; -- one small bridge used
			else
				core.add_node(p, {name="bridges:bridge_middle", param1=0, param2=fdir});
				rem_middle = rem_middle -1; -- one middle part used
			end

			i = i+1;
			end
		end


		-- do we have to give any leftover parts back?
		local meta = core.get_meta(pos);
		local inv = meta:get_inventory();

		if( rem_small > 0 ) then
			inv:add_item( "main", "bridges:bridge_small "..tostring( rem_small ));
		end

		if( rem_middle > 0 ) then
			inv:add_item( "main", "bridges:bridge_middle "..tostring( rem_middle ));
		end
	end,
})


core.register_craft({
	output = "bridges:bridge_auto",
	recipe = {
		{ "bridges:bridge_large", "bridges:bridge_large", "bridges:bridge_large" },
		{ "bridges:bridge_large", "bridges:bridge_large", "bridges:bridge_large" },
		{ "bridges:bridge_large", "bridges:bridge_large", "bridges:bridge_large" },
	}
});