<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<el:level xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://enigma-game.org/schema/level/1 level.xsd" xmlns:el="http://enigma-game.org/schema/level/1">
  <el:protected>
    <el:info el:type="library">
      <el:identity el:title="" el:id="lib/libflood"/>
      <el:version el:score="1" el:release="1" el:revision="6" el:status="released"/>
      <el:author  el:name="Raoul Bourquin" el:email="" el:homepage=""/>
      <el:copyright>Copyright © 2007 Raoul Bourquin</el:copyright>
      <el:license el:type="GPL v2.0 or above" el:open="true"/>
      <el:compatibility el:enigma="0.92">
      </el:compatibility>
      <el:modes el:easy="false" el:single="false" el:network="false"/>
      <el:comments>
        <el:code>Lua 5.1 and XML converted by Leveladministrators</el:code>
      </el:comments>
      <el:score el:easy="-" el:difficult="-"/>
    </el:info>
    <el:luamain><![CDATA[
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-- REFERENCE --
---------------
-- Parameters:
--
-- land_map: Charmap containig the landscape with the (un)floodable floors
-- Allowed chars: "#" : unfloodable
--                " " : floodable, not yet flooded
--                "~" : flooded (is water)
--
-- top_left: Array with the real levelcoordinates of the top left corner.
-- 
-- flood_method: Method to determine the next tiles.
-- This can be: 1 : only examine the north, east, south and west field
--              2 : examine all 8 neighbour fields
--
-- Used Globals (interesting for programmers only):
-- flood_map: Arraymap with the current state of the flood, starts as copy of land_map
-- flood_front: Coordinates of all tiles to examine in this step
-- to_flood: All tiles that will be flooded at the end of this step

-- Defaults:
-- Declare all as local to avoid a conflict with variables maybe used by the levelauthors
local land_map = nil
local top_left = nil
local flood_method = nil
local flood_map = nil
local flood_front = nil
local to_flood = nil

function init_flood(new_map, corner, method)
    -- Set defaults if no values are given:
    if new_map ~= nil then
        land_map = new_map
    else
        land_map = {"~"}
    end
    if corner ~= nil then
        top_left = corner
    else
        top_left = {0,0}
    end
    if flood_method ~= nil then
        flood_method = method
    else
        flood_method = 1
    end

    -- Is the map bigger than 0 x 0 ?
    local x, y = get_map_size(land_map)
    if x < 1 or y < 1 then
        error("init_flood(new_map, corner, method): Map "..tostring(x).." x "..tostring(y).." is too small!\n")
    end
    -- Is the map rectangular?
    is_rectangular()
    -- Test top_left corner for valid koordinates
    -- We do not test, if the map is bigger than the level!
    -- The bottom right corner may lie outside of the level -> flood_it will raise an error ...
    if top_left[1] < 0 or top_left[2] < 0 then
        error("init_flood(new_map, corner, method): Invalid value for top left map corner! "..tostring(top_left[1])..";"..tostring(top_left[2]).."\n")
    end
    -- Valid flood method?
    if flood_method ~= 1 and flood_method ~= 2 then
        error("init_flood(new_map, corner, method): Invalid value for method: "..tostring(method).."! Values are 1 or 2.\n")
    end

    -- Build up the flood_map table.
    build_up_flood_map(land_map)
    -- Build up the data for a new flood_front.
    new_flood_front()
    search_initial_water()
    -- Now draw the initial waterspots.
    flood_it(flood_front,top_left)
    return 0
end

function do_flood()
    -- Create a new global to_flood.
    new_to_flood()
    -- Iterate over all elements in flood_front to find the tiles, we have to flood.
    local flood_front_size = table.getn(flood_front)
    -- DEBUG:
    --print("Flood Front has size: "..tostring(flood_front_size))
    
    local k,v
    for k,v in pairs(flood_front) do
        local akt_pos = flood_front[k]
        if flood_method == 1 then
            examine_field_nesw(akt_pos[1], akt_pos[2])
        elseif flood_method == 2 then
            examine_field_all8(akt_pos[1], akt_pos[2])
        end
    end

    -- Write the to_flood to flood_front.
    clear_flood_front()
    copy_to_flood_to_flood_front()
    -- We don't need to update the flood_map, because we updated it in
    -- examine_field_neighbour(x,y). This improves performance a big bit!
    --update_flood_map()
    -- FLOOD!
    flood_it(to_flood,top_left)
    return 0
end
--------------------------------------------------------------------------------
-- Export public functions:
-- Not yet used
--init_flood = init_flood
--do_flood = do_flood
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-- Get the dimensions of the land_map:
function get_map_size(land_map)
    local y_size=table.getn(land_map)
    local x_size=string.len(land_map[1])
    return x_size, y_size
end

-- Get the dimensions of the flood_map:
function get_flood_map_size(flood_map)
    local y_size=table.getn(flood_map)
    local x_size=table.getn(flood_map[1])
    return x_size, y_size
end

-- This function is not used anymore
function is_inside_map(x,y)
    -- Test, if x and y are inside the flood_map. If no, raise an error.
    local x_size, y_size = get_flood_map_size(flood_map)
    if x > x_size then
        error("is_inside_map(x,y): x is not inside the map! "..tostring(x).."\n")
    end
    if y > y_size then
        error("is_inside_map(x,y): y is not inside the map! "..tostring(y).."\n")
    end
end

function is_on_border(x,y)
    -- Test, if x and y are on the flood_map border.
    local x_size, y_size = get_flood_map_size(flood_map)
    local on_left, on_right, on_top, on_bottom = false, false, false, false
    if x == 1 then
        -- is on left border
        on_left = true
    end
    if x == x_size then
        -- is on right border
        on_right = true
    end
    if y == 1 then
        -- is on top border
        on_top = true
    end
    if y == y_size then
        -- is on bottom border
        on_bottom = true
    end
    return on_left, on_right, on_top, on_bottom
end

function is_rectangular()
    local x_size, y_size = get_map_size(land_map)
    -- Length of the first line in the map:
    local buffer = string.len(land_map[1])
    local i, temp
    for i=1, y_size do
        temp = string.len(land_map[i])
        if temp ~= buffer then
            error("init_flood(new_map, corner, method): Map is not rectangular!\n")
        end
    end
    return 0
end
--------------------------------------------------------------------------------
function get_specific_char(x,y)
    local akt_line = land_map[y]
    local this_char = string.sub(akt_line,x,x)
    return this_char
end

function parse_this_char(akt_char)
    if akt_char == "#" then
        -- Unfloodable
        return 0
    elseif akt_char == " " then
        -- Floodable, not yet flooded
        return 1
    elseif akt_char == "~" then
        -- Floodable, flooded
        return 2
    else
        error("init_flood(new_map, corner, method): Illegal char \""..akt_char.."\" in the map! Valid chars are: [#, ,~].\n")
    end
end

function build_up_flood_map(land_map)
    -- new global:
    flood_map={}
    local x_size, y_size = get_map_size(land_map)
    -- build up the flood_map table:
    local i,j
    for i=1, y_size do
        -- each line is a table:
        flood_map[i]={}
        for j=1, x_size do
            local akt_char = get_specific_char(j,i)
            flood_map[i][j] = parse_this_char(akt_char)
        end
    end
    return 0
end
--------------------------------------------------------------------------------
function modify_flood_map(x,y,type)
    -- Not needed, calls from within this lib are valid
    --is_inside_map(x,y)
    -- type valid?
    --if type ~= 0 and type ~= 1 and type ~= 2 then
    --    error("modify_flood_map(x,y,type): Illegal type! "..tostring(type).."\n")
    --end
    flood_map[y][x] = type
    return 0
end
--------------------------------------------------------------------------------
function new_flood_front()
    -- new global:
    flood_front = {}
    return 0
end

function add_to_flood_front(x,y)
    local this_pos = {x,y}
    table.insert(flood_front,this_pos)
    return 0
end
--------------------------------------------------------------------------------
function search_initial_water()
    local x_size, y_size = get_flood_map_size(flood_map)
    local has_any_water = 0
    local i,j
    for i=1, y_size do
        for j=1, x_size do
            if flood_map[i][j] == 2 then
                has_any_water = has_any_water+1
                add_to_flood_front(j,i)
            end
        end
    end
    if has_any_water == 0 then
        error("init_flood(new_map, corner, method): No water found! Please set at least 1 water tile!\n")
    end
    return 0
end
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
function new_to_flood()
    -- new global:
    to_flood = {}
    return 0
end

function add_to_flood(x,y)
    local this_pos = {x,y}
    table.insert(to_flood,this_pos)
    return 0
end
--------------------------------------------------------------------------------
---F-L-O-O-D---M-E-T-H-O-D-S----------------------------------------------------
-- Method 1:
function examine_field_nesw(x,y)
    -- Check, if x or y is out of the flood_map bounds
    -- Not needed, calls from within this lib are valid
    --is_inside_map(x,y)

    local on_left, on_right, on_top, on_bottom = is_on_border(x,y)
    -- NORTH
    if not on_top then
        examine_field_neighbour(x,y-1)
    end
    -- EAST
    if not on_right then
        examine_field_neighbour(x+1,y)
    end
    -- SOUTH
    if not on_bottom then
        examine_field_neighbour(x,y+1)
    end
    -- WEST
    if not on_left then
        examine_field_neighbour(x-1,y)
    end
    return 0
end

-- Method 2:
function examine_field_all8(x,y)
    -- Check, if x or y is out of the flood_map bounds
    -- Not needed, calls from within this lib are valid
    --is_inside_map(x,y)

    local on_left, on_right, on_top, on_bottom = is_on_border(x,y)
    -- NORTH
    if not on_top then
        examine_field_neighbour(x,y-1)
        -- Check also for north-west and north-east
        if not on_left then
            examine_field_neighbour(x-1,y-1)
        end
        if not on_right then
            examine_field_neighbour(x+1,y-1)
        end
    end
    -- EAST
    if not on_right then
        examine_field_neighbour(x+1,y)
    end
    -- SOUTH
    if not on_bottom then
        examine_field_neighbour(x,y+1)
        -- Check also for south-west and south-east
        if not on_left then
            examine_field_neighbour(x-1,y+1)
        end
        if not on_right then
            examine_field_neighbour(x+1,y+1)
        end
    end
    -- WEST
    if not on_left then
        examine_field_neighbour(x-1,y)
    end
    return 0
end
--------------------------------------------------------------------------------
function examine_field_neighbour(x,y)
    -- What sort of floor is the examined position?
    if flood_map[y][x] == 0 then
        -- DEBUG:
        --print("Stone found at: "..tostring(x)..";"..tostring(y).."\n")
    elseif flood_map[y][x] == 1 then
        -- the only case we have to do something
        -- DEBUG:
        --print("Floodable ground found at: "..tostring(x)..";"..tostring(y).."\n")
        add_to_flood(x,y)
        -- Mark field as flooded in flood_map here will improve performance!!
        modify_flood_map(x, y, 2)
    elseif flood_map[y][x] == 2 then
        -- DEBUG:
        --print("Water found at: "..tostring(x)..";"..tostring(y).."\n")
    -- If there are more possibilities, add more elseifs here.
    -- We need no default-error, because flood_map IS clean.
    -- Errors were detected in parse_this_char().
    end
end
--------------------------------------------------------------------------------
function clear_flood_front()
    -- Just recreate the var.
    new_flood_front()
    return 0
end

function copy_to_flood_to_flood_front()
    local tab_size = table.getn(to_flood)
    for i=1, tab_size do
        local temp = to_flood[i]
        local temp_x = temp[1]
        local temp_y = temp[2]
        add_to_flood_front(temp_x,temp_y)
    end
    return 0
end

-- Fill the flood_map with the additional flooded fields. This is obsolete since
-- we add the fields just when they are detected.
function update_flood_map()
    local tab_size = table.getn(flood_front)
    for i=1, tab_size do
        local temp = to_flood[i]
        local temp_x = temp[1]
        local temp_y = temp[2]
        modify_flood_map(temp_x, temp_y, 2)
    end
    return 0
end
--------------------------------------------------------------------------------
function flood_it(map,top_left)
    local k, v
    for k,v in pairs(map) do
        local akt_pos = map[k]
        set_floor("fl-water", top_left[1]+akt_pos[1]-1, top_left[2]+akt_pos[2]-1)
    end
end
--------------------------------------------------------------------------------
---E--N--D------O--F------L--I--B--F--L--O--O--D--------------------------------
--------------------------------------------------------------------------------
    ]]></el:luamain>
    <el:i18n>
    </el:i18n>
  </el:protected>
</el:level>