DEV Community: nshmura

[Minecraft][Forge 1.16] Extrem Explosion Mod

nshmura — Sun, 15 Aug 2021 07:39:26 +0000

I write minecraft mod which explode blocks extremely.

package com.nshmura.doromod;

import net.minecraft.client.Minecraft
import net.minecraft.util.ResourceLocation
import net.minecraft.util.math.vector.Vector3d
import net.minecraft.world.Explosion
import net.minecraftforge.common.MinecraftForge
import net.minecraftforge.event.TickEvent
import net.minecraftforge.event.entity.player.PlayerInteractEvent
import net.minecraftforge.eventbus.api.SubscribeEvent
import net.minecraftforge.fml.common.Mod
import net.minecraftforge.fml.network.NetworkEvent
import net.minecraftforge.fml.network.NetworkRegistry
import net.minecraftforge.fml.network.simple.SimpleChannel
import net.minecraftforge.fml.server.ServerLifecycleHooks
import org.apache.logging.log4j.LogManager
import org.apache.logging.log4j.Logger
import java.util.function.Supplier


@Mod(ExampleMod.MOD_ID)
class ExampleMod {
    private val logger: Logger = LogManager.getLogger(MOD_ID)

    private val channel: SimpleChannel = NetworkRegistry.newSimpleChannel(
        ResourceLocation(MOD_ID, "main"),
        { PROTOCOL_VERSION },
        PROTOCOL_VERSION::equals,
        PROTOCOL_VERSION::equals
    )

    private var explosions: List<ContinuousExplosion> = emptyList()

    init {
        channel.registerMessage(
            0,
            ExplosionMessage::class.java,
            ExplosionMessage::encode,
            ExplosionMessage::from,
            this::handle
        )

        MinecraftForge.EVENT_BUS.register(this)
    }

    @SubscribeEvent
    fun on(event: PlayerInteractEvent.LeftClickEmpty) {
        val loc = Minecraft.getInstance().hitResult?.location
            ?: return
        logger.info("[HIT] ${loc.x} ${loc.y} ${loc.z}")

        explosions = explosions.plus(ContinuousExplosion(event, loc))
    }

    @SubscribeEvent
    fun on(event: TickEvent.ClientTickEvent) {
        explosions = explosions.mapNotNull {
            it.tick(event) { message ->
                channel.sendToServer(message)
                logger.info("[POS] ${message.x} ${message.y} ${message.z}")
            }
        }
    }

    private fun handle(message: ExplosionMessage, context: Supplier<NetworkEvent.Context>) {
        logger.info("[EXP] ${message.x} ${message.y}  ${message.z} ")

        ServerLifecycleHooks.getCurrentServer().overworld().explode(
            null,
            message.x,
            message.y,
            message.z,
            message.size,
            Explosion.Mode.BREAK
        )
    }

    companion object {
        const val MOD_ID: String = "doro_mod"
        private const val PROTOCOL_VERSION = "1"
    }
}

class ContinuousExplosion(
    private val event: PlayerInteractEvent.LeftClickEmpty,
    private val location: Vector3d
) {
    private var explodeCount = 0
    private var tickCount = 0

    fun tick(tick: TickEvent, handler: (ExplosionMessage) -> Unit): ContinuousExplosion? {
        if (tick.phase != TickEvent.Phase.START) {
            return this
        }
        tickCount++
        if (tickCount % WAIT_TICK != 0) {
            return this
        }

        val pos = moveTo(location, event.player.lookAngle, explodeCount * EXPLODE_DISTANCE)
        handler(ExplosionMessage(pos.x, pos.y, pos.z, EXPLODE_SIZE))

        explodeCount++
        return if (explodeCount >= EXPLODE_COUNT) {
            null
        } else {
            this
        }
    }

    private fun moveTo(position: Vector3d, angle: Vector3d, multiply: Double) =
        Vector3d(
            position.x + angle.x * multiply,
            position.y + angle.y * multiply,
            position.z + angle.z * multiply
        )

    companion object {
        private const val WAIT_TICK = 5
        private const val EXPLODE_COUNT = 25
        private const val EXPLODE_SIZE = 16F
        private const val EXPLODE_DISTANCE = 5.toDouble()
    }
}

[Minecraft - Forge 1.16] Make explosion from client.

nshmura — Sat, 14 Aug 2021 06:02:00 +0000

I built Explosion Mod in following sequence.

Receive PlayerInteractEvent.LeftClickEmpty in client side.
Send ExplosionMessage to server side.
Make explosion in server side.

Code is written in Kotlin.

First, make ExplosionMessage class.

class ExplosionMessage(
    val x: Double,
    val y: Double,
    val z: Double
) {

    companion object {
        fun encode(message: ExplosionMessage, buf: PacketBuffer) {
            buf.writeDouble(message.x)
            buf.writeDouble(message.y)
            buf.writeDouble(message.z)
        }

        fun from(buf: PacketBuffer): ExplosionMessage {
            return ExplosionMessage(
                buf.readDouble(),
                buf.readDouble(),
                buf.readDouble()
            )
        }
    }
}

Prepare SimpleChannel.

class ExampleMod {

    private val channel: SimpleChannel = NetworkRegistry.newSimpleChannel(
        ResourceLocation(MOD_ID, "main"),
        { PROTOCOL_VERSION },
        PROTOCOL_VERSION::equals,
        PROTOCOL_VERSION::equals
    )

    init {
        channel.registerMessage(
            0,
            ExplosionMessage::class.java,
            ExplosionMessage::encode,
            ExplosionMessage::from,
            this::handle
        )

        MinecraftForge.EVENT_BUS.register(this)
    }

    ...

Receive PlayerInteractEvent.LeftClickEmpty.
This event is occurred in client side only.

    @SubscribeEvent
    fun on(event: PlayerInteractEvent.LeftClickEmpty) {
        val loc = Minecraft.getInstance().hitResult?.location
        if (loc == null) {
            return
        }

        logger.info("ExplosionMessage send: ${loc?.x} ${loc?.y} ${loc?.z} ")
        channel.sendToServer(ExplosionMessage(loc.x, loc.y, loc.z))
    }

Handle ExplosionMessage.

    fun handle(message: ExplosionMessage, context: Supplier<NetworkEvent.Context>) {
        logger.info("ExplosionMessage received: ${message.x} ${message.y}  ${message.z} ")

        ServerLifecycleHooks.getCurrentServer().overworld().explode(
            null,
            message.x,
            message.y,
            message.z,
            4.0F,
            Explosion.Mode.BREAK
        )
    }

Now we can explode any place where we want!

[Kotlin] ::class.java “Unresolved Reference: Java” error

nshmura — Sat, 14 Aug 2021 05:17:49 +0000

I got “Unresolved Reference: Java” error in following code.

val clazz = String::class.java

Loading kotlin-reflect library in build.gradle resolved this error.

dependencies {
    ...
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"

    // this line
    implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
    ...
}

[mincraft][forge1.16] example code: Explode on block placed

nshmura — Mon, 09 Aug 2021 04:10:00 +0000

Make explode on BlockEvent.EntityPlaceEvent

package com.nshmura.doromod;

import net.minecraft.entity.Entity;
import net.minecraft.world.Explosion;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.event.world.BlockEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

@Mod(ExampleMod.MOD_ID)
public class ExampleMod {
    public static final String MOD_ID = "examplemod";

    // Directly reference a log4j logger.
    private static final Logger LOGGER = LogManager.getLogger(MOD_ID);

    public ExampleMod() {
        MinecraftForge.EVENT_BUS.register(this);
    }

    @SubscribeEvent
    public void on(BlockEvent.EntityPlaceEvent event) {
        Entity entity = event.getEntity();
        entity.getCommandSenderWorld().explode(
                entity,
                entity.position().x,
                entity.position().y,
                entity.position().z,
                4.0F,
                Explosion.Mode.NONE
        );
    }
}