MixinIBiomeReader.java

package corgiaoc.byg.mixin.common.world;

import corgiaoc.byg.util.noise.fastnoise.FastNoise;
import net.minecraft.server.MinecraftServer;
import net.minecraft.util.ResourceLocation;
import net.minecraft.util.registry.Registry;
import net.minecraft.world.World;
import net.minecraft.world.biome.Biome;
import net.minecraft.world.biome.BiomeManager;
import net.minecraft.world.server.ServerWorld;
import net.minecraftforge.fml.server.ServerLifecycleHooks;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Inject;
import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;

import java.util.Optional;

@Mixin(BiomeManager.IBiomeReader.class)
public class MixinIBiomeReader {

    private static long seed;
    private static FastNoise noise;
    private static FastNoise noise2;


    @Inject(method = "getNoiseBiome", at = @At("HEAD"), cancellable = true)
    private void addRigidRiversToAllBiomeProviders(int x, int y, int z, CallbackInfoReturnable<Biome> cir) {
        MinecraftServer currentServer = ServerLifecycleHooks.getCurrentServer();
        ServerWorld world = currentServer.getWorld(World.OVERWORLD);
        setupRiverNoise(world == null ? 1000 : world.getSeed());

        double noiseVal = noise.GetNoise(x, z) * 10;
        float noise2Val = noise2.GetNoise(x, z);

        if (noiseVal > 5.391 + Math.abs(noise2Val * 0.4) && noiseVal < 5.8 + Math.abs(noise2Val * 0.4)) {
            Optional<Biome> optional = currentServer.func_244267_aX().getRegistry(Registry.BIOME_KEY).getOptional(new ResourceLocation("minecraft:river"));
            optional.ifPresent(cir::setReturnValue);
        }
    }

    private static void setupRiverNoise(long serverSeed) {
        if (seed != serverSeed || noise == null || noise2 == null) {
            seed = serverSeed;
            noise = new FastNoise((int) seed);
            noise.SetFractalType(FastNoise.FractalType.RigidMulti);
            noise.SetNoiseType(FastNoise.NoiseType.CubicFractal);
            noise.SetGradientPerturbAmp(1);
            noise.SetFractalOctaves(5);
            noise.SetFractalGain(0.3f);
            noise.SetFrequency(0.002F);

            noise2 = new FastNoise((int) seed);
            noise2.SetFractalType(FastNoise.FractalType.Billow);
            noise2.SetNoiseType(FastNoise.NoiseType.SimplexFractal);
            noise2.SetGradientPerturbAmp(1);
            noise2.SetFractalOctaves(5);
            noise2.SetFractalGain(0.3f);
            noise2.SetFrequency(0.02F);
        }
    }
}