ModifiableBiomeInfo.java

/*
 * Copyright (c) Forge Development LLC and contributors
 * SPDX-License-Identifier: LGPL-2.1-only
 */

package net.minecraftforge.common.world;

import java.util.List;
import java.util.Locale;

import org.jetbrains.annotations.ApiStatus;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import net.minecraft.core.Holder;
import net.minecraft.world.level.biome.Biome;
import net.minecraft.world.level.biome.Biome.ClimateSettings;
import net.minecraft.world.level.biome.BiomeGenerationSettings;
import net.minecraft.world.level.biome.BiomeSpecialEffects;
import net.minecraft.world.level.biome.MobSpawnSettings;

/**
 * Holds lazy-evaluable modified biome info.
 * Memoizers are not used because it's important to return null
 * without evaluating the biome info if it's accessed outside of a server context.
 */
public class ModifiableBiomeInfo {
    @NotNull
    private final BiomeInfo originalBiomeInfo;
    @Nullable
    private BiomeInfo modifiedBiomeInfo = null;

    /**
     * @param originalBiomeInfo BiomeInfo representing the original state of a biome when the biome was constructed.
     */
    public ModifiableBiomeInfo(@NotNull final BiomeInfo originalBiomeInfo) {
        this.originalBiomeInfo = originalBiomeInfo;
    }

    /**
     * {@return The modified biome info if modified biome info has been generated, otherwise gets original biome info}
     */
    @NotNull
    public BiomeInfo get() {
        return this.modifiedBiomeInfo == null
            ? originalBiomeInfo
            : modifiedBiomeInfo;
    }

    /**
     * {@return The original biome info that the associated biome was created with}
     */
    @NotNull
    public BiomeInfo getOriginalBiomeInfo() {
        return this.originalBiomeInfo;
    }

    /**
     * {@return Modified biome info; null if it hasn't been set yet}
     */
    @Nullable
    public BiomeInfo getModifiedBiomeInfo() {
        return this.modifiedBiomeInfo;
    }

    /**
     * Internal forge method; the game will crash if mods invoke this.
     * Creates and caches the modified biome info.
     * @param biome named biome with original data.
     * @param biomeModifiers biome modifiers to apply.
     *
     * @throws IllegalStateException if invoked more than once.
     */
    @ApiStatus.Internal
    public void applyBiomeModifiers(final Holder<Biome> biome, final List<BiomeModifier> biomeModifiers) {
        if (this.modifiedBiomeInfo != null)
            throw new IllegalStateException(String.format(Locale.ENGLISH, "Biome %s already modified", biome));

        var original = this.getOriginalBiomeInfo();
        var builder = BiomeInfo.Builder.copyOf(original);
        for (var phase : BiomeModifier.Phase.values()) {
            for (var modifier : biomeModifiers)
                modifier.modify(biome, phase, builder);
        }
        this.modifiedBiomeInfo = builder.build();
    }

    /**
     * Record containing raw biome data.
     * @param climateSettings Weather and temperature settings.
     * @param effects Client-relevant effects for rendering and sound.
     * @param generationSettings Worldgen features and carvers.
     * @param mobSpawnSettings Mob spawn settings.
     */
    public record BiomeInfo(ClimateSettings climateSettings, BiomeSpecialEffects effects, BiomeGenerationSettings generationSettings, MobSpawnSettings mobSpawnSettings) {
        public static class Builder {
            private ClimateSettingsBuilder climateSettings;
            private BiomeSpecialEffectsBuilder effects;
            private BiomeGenerationSettings.PlainBuilder generationSettings;
            private MobSpawnSettingsBuilder mobSpawnSettings;

            /**
             * @param original the biome to copy
             * @return A ModifiedBiomeInfo.Builder with a copy of the biome's data
             */
            public static Builder copyOf(final BiomeInfo original) {
                final ClimateSettingsBuilder climateBuilder = ClimateSettingsBuilder.copyOf(original.climateSettings());
                final BiomeSpecialEffectsBuilder effectsBuilder = BiomeSpecialEffectsBuilder.copyOf(original.effects());
                final var generationBuilder = new BiomeGenerationSettings.PlainBuilder();
                generationBuilder.addFrom(original.generationSettings());
                final MobSpawnSettingsBuilder mobSpawnBuilder = new MobSpawnSettingsBuilder(original.mobSpawnSettings());

                return new Builder(
                    climateBuilder,
                    effectsBuilder,
                    generationBuilder,
                    mobSpawnBuilder
                );
            }

            private Builder(final ClimateSettingsBuilder climateSettings, final BiomeSpecialEffectsBuilder effects, final BiomeGenerationSettings.PlainBuilder generationSettings, final MobSpawnSettingsBuilder mobSpawnSettings) {
                this.climateSettings = climateSettings;
                this.effects = effects;
                this.generationSettings = generationSettings;
                this.mobSpawnSettings = mobSpawnSettings;
            }

            public BiomeInfo build() {
                return new BiomeInfo(this.climateSettings.build(), this.effects.build(), this.generationSettings.build(), this.mobSpawnSettings.build());
            }

            public ClimateSettingsBuilder getClimateSettings() {
                return climateSettings;
            }

            public BiomeSpecialEffectsBuilder getSpecialEffects() {
                return effects;
            }

            public BiomeGenerationSettings.PlainBuilder getGenerationSettings() {
                return generationSettings;
            }

            public MobSpawnSettingsBuilder getMobSpawnSettings() {
                return mobSpawnSettings;
            }
        }
    }
}