com.yungnickyoung.minecraft.yungsapi.api.world.randomize.ItemRandomizer Maven / Gradle / Ivy
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A common API for YUNG's Minecraft mods
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package com.yungnickyoung.minecraft.yungsapi.api.world.randomize;
import com.mojang.serialization.Codec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import com.yungnickyoung.minecraft.yungsapi.YungsApiCommon;
import net.minecraft.Util;
import net.minecraft.core.registries.BuiltInRegistries;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.nbt.ListTag;
import net.minecraft.util.RandomSource;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.Items;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
/**
* Describes a set of Items and the probability of each Item in the set being chosen.
* This is very useful for easily adding random variation to things like armor stands during world generation.
*/
public class ItemRandomizer {
public static final Codec CODEC = RecordCodecBuilder.create((instance) -> instance
.group(
Entry.CODEC.listOf().fieldOf("entries").forGetter((randomizer) -> randomizer.entries),
BuiltInRegistries.ITEM.byNameCodec().fieldOf("defaultItem").forGetter((randomizer) -> randomizer.defaultItem))
.apply(instance, ItemRandomizer::new));
/**
* Map of Items to their corresponding probabilities.
* The total sum of all the probabilities should not exceed 1.
*/
private List entries = new ArrayList<>();
/**
* The default Item is used for any leftover probability ranges.
* For example, if the total sum of all the probabilities of the entries is 0.6, then
* there is a 0.4 chance of the defaultItem being selected.
*/
private Item defaultItem = Items.AIR;
/**
* Saves this ItemRandomizer to a new CompoundTag.
* @return The CompoundTag
*/
public CompoundTag saveTag() {
CompoundTag compoundTag = new CompoundTag();
// Save default blockstate
compoundTag.putInt("defaultItemId", BuiltInRegistries.ITEM.getId(this.defaultItem));
// Save entries
ListTag entriesTag = Util.make(new ListTag(), (tag) -> {
this.entries.forEach((entry) -> {
CompoundTag entryTag = new CompoundTag();
entryTag.putInt("entryItemId", BuiltInRegistries.ITEM.getId(entry.item));
entryTag.putFloat("entryChance", entry.probability);
tag.add(entryTag);
});
});
compoundTag.put("entries", entriesTag);
return compoundTag;
}
/**
* Constructs a new ItemRandomizer from a CompoundTag.
* @param compoundTag The CompoundTag
*/
public ItemRandomizer(CompoundTag compoundTag) {
this.defaultItem = BuiltInRegistries.ITEM.byId(compoundTag.getInt("defaultItemId"));
this.entries = new ArrayList<>();
ListTag entriesTag = compoundTag.getList("entries", 10);
entriesTag.forEach(entryTag -> {
CompoundTag entryCompoundTag = ((CompoundTag) entryTag);
Item item = BuiltInRegistries.ITEM.byId(entryCompoundTag.getInt("entryItemId"));
float chance = entryCompoundTag.getFloat("entryChance");
this.addItem(item, chance);
});
}
/**
* Constructs a new ItemRandomizer from a list of Entries and a default Item.
* @param entries List of Entries
* @param defaultItem The default Item
*/
public ItemRandomizer(List entries, Item defaultItem) {
this.entries = entries;
this.defaultItem = defaultItem;
}
/**
* Constructs a new ItemRandomizer with only a default Item.
* @param defaultItem The default Item
*/
public ItemRandomizer(Item defaultItem) {
this.defaultItem = defaultItem;
}
/**
* Constructs a new ItemRandomizer with no default Item nor entries.
*/
public ItemRandomizer() {
}
/**
* Convenience factory function to construct an ItemRandomizer from a list of Items.
* Each Item will have equal probability of being chosen.
*/
public static ItemRandomizer from(Item... items) {
ItemRandomizer randomizer = new ItemRandomizer();
float chance = 1f / items.length;
for (Item item : items) {
randomizer.addItem(item, chance);
}
return randomizer;
}
/**
* Adds an Item with given chance of being selected.
* @return The modified ItemRandomizer
*/
public ItemRandomizer addItem(Item item, float chance) {
// Abort if Item already a part of this randomizer
if (entries.stream().anyMatch(entry -> entry.item.equals(item))) {
YungsApiCommon.LOGGER.warn("WARNING: duplicate item {} added to ItemRandomizer!", item.toString());
return this;
}
// Attempt to add Item to entries
float currTotal = entries.stream().map(entry -> entry.probability).reduce(Float::sum).orElse(0f);
float newTotal = currTotal + chance;
if (newTotal > 1) { // Total probability cannot exceed 1
YungsApiCommon.LOGGER.warn("WARNING: item {} added to ItemRandomizer exceeds max probabiltiy of 1!", item.toString());
return this;
}
entries.add(new Entry(item, chance));
return this;
}
/**
* Randomly selects an Item from this ItemRandomizer.
* The random provided should be one used in generation of your structure or feature,
* to ensure reproducibility for the same world seed.
*/
public Item get(Random random) {
float target = random.nextFloat();
float currBottom = 0;
for (Entry entry : entries) {
if (currBottom <= target && target < currBottom + entry.probability) {
return entry.item;
}
currBottom += entry.probability;
}
// No match found
return this.defaultItem;
}
/**
* Randomly selects an Item from this ItemRandomizer.
* The RandomSource provided should be one used in generation of your structure or feature,
* to ensure reproducibility for the same world seed.
*/
public Item get(RandomSource randomSource) {
float target = randomSource.nextFloat();
float currBottom = 0;
for (Entry entry : entries) {
if (currBottom <= target && target < currBottom + entry.probability) {
return entry.item;
}
currBottom += entry.probability;
}
// No match found
return this.defaultItem;
}
/**
* Sets the default Item.
* The default Item is used for any leftover probability ranges.
*/
public void setDefaultItem(Item item) {
this.defaultItem = item;
}
/**
* Returns a Map of Items to their corresponding probabilities.
* Does not include the default Item.
* @return The Map
*/
public Map getEntriesAsMap() {
Map map = new HashMap<>();
this.entries.forEach(entry -> map.put(entry.item, entry.probability));
return map;
}
/**
* Returns a List of Entries.
* @return The List
*/
public List getEntries() {
return entries;
}
/**
* Returns the default Item.
* @return The default Item
*/
public Item getDefaultItem() {
return defaultItem;
}
/**
* Represents an Item and its corresponding probability of being chosen.
*/
public static class Entry {
public static Codec CODEC = RecordCodecBuilder.create(instance -> instance
.group(
BuiltInRegistries.ITEM.byNameCodec().fieldOf("item").forGetter((entry) -> entry.item),
Codec.floatRange(0.0F, 1.0F).fieldOf("probability").forGetter(entry -> entry.probability))
.apply(instance, Entry::new));
public Item item;
public float probability;
public Entry(Item item, float probability) {
this.item = item;
this.probability = probability;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof Entry) {
return this.item.equals(((Entry) obj).item);
} else if (obj instanceof Item) {
return this.item.equals(obj);
}
return false;
}
}
}