Mineclonia/mods/CORE/mcl_loot/init.lua

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mcl_loot = {}
--[[
Select a number of itemstacks out of a pool of treasure definitions randomly.
Parameters:
* loot_definitions: Probabilities and information about the loot to select. Syntax:
{
stacks_min = 1, -- Minimum number of item stacks to get. Default: 1
stacks_max = 3, -- Maximum number of item stacks to get. Default: 1
items = { -- Table of possible loot items. This function selects between stacks_min and stacks_max of these.
{
itemstring = "example:item1", -- Which item to select
amount_min = 1, -- Minimum size of itemstack. Must not be larger than 6553. Optional (default: 1)
amount_max = 10, -- Maximum size of item stack. Must not be larger than item definition's stack_max or 6553. Optional (default: 1)
wear_min = 1, -- Minimum wear value. Must be at least 1. Optional (default: no wear)
wear_max = 1, -- Maxiumum wear value. Must be at least 1. Optional (default: no wear)
weight = 5, -- Likelihood of this item being selected (see below). Optional (default: 1)
},
{ -- more tables like above, one table per item stack }
}
}
* pr: PseudoRandom object used for the randomness
How weight works: The probability of a single item stack being selected is weight/total_weight, with
total_weight being the sum of all weight values in the items table. If you leave out the weight for
all items, the likelihood of each item being selected is equal.
Returns: Table of itemstrings
]]
function mcl_loot.get_loot(loot_definitions, pr)
local items = {}
local total_weight = 0
for i=1, #loot_definitions.items do
total_weight = total_weight + (loot_definitions.items[i].weight or 1)
end
local stacks_min = loot_definitions.stacks_min
local stacks_max = loot_definitions.stacks_max
if not stacks_min then stacks_min = 1 end
if not stacks_max then stacks_max = 1 end
local stacks = pr:next(loot_definitions.stacks_min, loot_definitions.stacks_max)
for s=1, stacks do
local r = pr:next(1, total_weight)
local accumulated_weight = 0
local item
for i=1, #loot_definitions.items do
accumulated_weight = accumulated_weight + (loot_definitions.items[i].weight or 1)
if accumulated_weight >= r then
item = loot_definitions.items[i]
break
end
end
if item then
local itemstring = item.itemstring
if item.amount_min and item.amount_max then
itemstring = itemstring .. " " .. pr:next(item.amount_min, item.amount_max)
end
if item.wear_min and item.wear_max then
-- Sadly, PseudoRandom only allows very narrow ranges, so we set wear in steps of 10
local wear_min = math.floor(item.wear_min / 10)
local wear_max = math.floor(item.wear_max / 10)
local wear = pr:next(wear_min, wear_max) * 10
if not item.amount_min and not item.amount_max then
itemstring = itemstring .. " 1"
end
itemstring = itemstring .. " " .. tostring(wear)
end
table.insert(items, itemstring)
else
minetest.log("error", "[mcl_loot] INTERNAL ERROR! Failed to select random loot item!")
end
end
return items
end
--[[
Repeat mcl_loot.get_loot multiple times for various loot_definitions.
Useful for filling chests.
* multi_loot_definitions: Table of loot_definitions (see mcl_loot.get_loot)
* pr: PseudoRandom object used for the randomness
Returns: Table of itemstrings ]]
function mcl_loot.get_multi_loot(multi_loot_definitions, pr)
local items = {}
for m=1, #multi_loot_definitions do
local group = mcl_loot.get_loot(multi_loot_definitions[m], pr)
for g=1, #group do
table.insert(items, group[g])
end
end
return items
end