Fabric enters the world and generates 10 chicks

Project result

The goal is not to memorize the code, but to understand "what happened in the game world after the event was triggered."

In Fabric MOD, there is no specific player when "starting Minecraft", so the really suitable time to write generation logic is after the player enters the world. We use `ServerPlayConnectionEvents.JOIN` to listen for this moment and then create entities in the server world.

01

Trigger

The player enters the world, and Fabric's JOIN event hands the player object to us.

02

Positioning

Read the player in the direction, find a center point at 3 squares ahead and form two rows.

03

Generate

Create the entity on the server side, set the position and direction, and finally put it into the world.

Students control the chicken, cow, pig and block generation effects in a Minecraft-style world through code — From code to game world: The same generation logic can be replaced by different animals or by squares.

Mind map

Taking apart "generating chicks" is actually six small problems.

When to execute:Executed after the player enters the world, not when the MOD is first loaded.
On which end to execute:Entity generation is placed on the server side to prevent the client from seeing fake entities or repeated generation.
Where is generated:Calculate the forward position according to the player's orientation, and then give each chicken a little lateral offset.
How to ensure not to be embarrassed:Find a location with air above and blocks under your feet to reduce the chance of getting stuck in the ground.

Tip: If you get 10 extra chicks every time you re-enter the world, this is normal. This version demonstrates "trigger when entering the world". If you only want to trigger it when you enter for the first time, you can add player data records.

Build flow

Implementation process: Get the player first, then decide the position in front of you, and finally put the entity into the world.

Fabric player enters the world to generate entity flow chart — Flowchart: After the JOIN event is triggered, the player's orientation is read, the safe position is calculated, the entity is created, and then expanded into other gameplay methods.

Code guide

Code to add: one entrance registered, one player event class.

package mls.maik;

import mls.maik.block.ModBlocks;
import mls.maik.event.ModPlayerEvents;
import mls.maik.item.ModItems;
import net.fabricmc.api.ModInitializer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Maik implements ModInitializer {
    public static final String MOD_ID = "maik";
    public static final Logger LOGGER = LoggerFactory.getLogger(MOD_ID);

    @Override
    public void onInitialize() {
        ModBlocks.registerModBlocks();
        ModItems.registerModItems();
        ModPlayerEvents.register();
        LOGGER.info("Hello Fabric world!");
    }
}

package mls.maik.event;

import net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents;
import net.minecraft.entity.Entity;
import net.minecraft.entity.EntityType;
import net.minecraft.server.network.ServerPlayerEntity;
import net.minecraft.server.world.ServerWorld;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.Direction;

public class ModPlayerEvents {
    private static final int SPAWN_DISTANCE = 3;
    private static final int ENTITIES_PER_ROW = 5;

    public static void register() {
        ServerPlayConnectionEvents.JOIN.register((handler, sender, server) -> {
            ServerPlayerEntity player = handler.getPlayer();
            spawnEntityGrid(player, EntityType.CHICKEN, 10);
        });
    }

    private static void spawnEntityGrid(ServerPlayerEntity player, EntityType<? extends Entity> entityType, int count) {
        ServerWorld world = player.getServerWorld();
        Direction forward = player.getHorizontalFacing();
        Direction right = forward.rotateYClockwise();
        BlockPos center = player.getBlockPos().offset(forward, SPAWN_DISTANCE);

        for (int i = 0; i < count; i++) {
            int sideOffset = (i % ENTITIES_PER_ROW) - (ENTITIES_PER_ROW / 2);
            int forwardOffset = i / ENTITIES_PER_ROW;
            BlockPos spawnPos = center.offset(right, sideOffset).offset(forward, forwardOffset);

            Entity entity = entityType.create(world);
            if (entity != null) {
                BlockPos safePos = findSafeSpawnPos(world, spawnPos);
                entity.refreshPositionAndAngles(
                        safePos.getX() + 0.5,
                        safePos.getY(),
                        safePos.getZ() + 0.5,
                        player.getYaw() + 180.0F,
                        0.0F
                );
                world.spawnEntity(entity);
            }
        }
    }

    private static BlockPos findSafeSpawnPos(ServerWorld world, BlockPos startPos) {
        for (int yOffset = 2; yOffset >= -3; yOffset--) {
            BlockPos pos = startPos.up(yOffset);
            if (world.getBlockState(pos).isAir()
                    && world.getBlockState(pos.up()).isAir()
                    && !world.getBlockState(pos.down()).isAir()) {
                return pos;
            }
        }

        return startPos;
    }
}

// 10 只小鸡
spawnEntityGrid(player, EntityType.CHICKEN, 10);

// 6 头牛
spawnEntityGrid(player, EntityType.COW, 6);

// 8 只猪
spawnEntityGrid(player, EntityType.PIG, 8);

// 4 只狼
spawnEntityGrid(player, EntityType.WOLF, 4);

// 5 只僵尸。注意：僵尸是敌对生物，生存模式里会攻击玩家。
spawnEntityGrid(player, EntityType.ZOMBIE, 5);

import mls.maik.block.ModBlocks;
import net.minecraft.block.Block;
import net.minecraft.block.Blocks;

// 在 register() 中可以这样调用：
placeBlocksInFront(player, Blocks.DIAMOND_BLOCK, 10);
placeBlocksInFront(player, ModBlocks.ggblock, 10);

private static void placeBlocksInFront(ServerPlayerEntity player, Block block, int count) {
    ServerWorld world = player.getServerWorld();
    Direction forward = player.getHorizontalFacing();
    Direction right = forward.rotateYClockwise();
    BlockPos center = player.getBlockPos().offset(forward, SPAWN_DISTANCE);

    for (int i = 0; i < count; i++) {
        int sideOffset = (i % ENTITIES_PER_ROW) - (ENTITIES_PER_ROW / 2);
        int forwardOffset = i / ENTITIES_PER_ROW;
        BlockPos pos = center.offset(right, sideOffset).offset(forward, forwardOffset);

        if (world.getBlockState(pos).isAir()) {
            world.setBlockState(pos, block.getDefaultState());
        }
    }
}

Why is the code written as independent `ModPlayerEvents`?

The main class `Maik` is responsible for registering all modules, and the event class is responsible for the logic after the player enters the world. In the future, if you want to change to generate other entities, add particles, or give text prompts to the player, you can all adjust them in this file.

Key ideas

Let’s clarify some of the most confusing points first.

01

Not client generated

The logic that truly changes the world in Minecraft must be placed on the server side. `player.getServerWorld()` here is the key.

02

Not randomly placed

`getHorizontalFacing()` will give the direction the player is facing, and `rotateYClockwise()` can calculate the right direction for queuing.

03

Not directly inserting coordinates

The entity position is set with `refreshPositionAndAngles`, and finally put into the world with `world.spawnEntity(entity)`.

04

Safe location is important

If the foot is air, the chick may fall; if the body position is not air, it may get stuck in the block.

05

The quantity can be adjusted by yourself

The last number of `spawnEntityGrid(player, EntityType.CHICKEN, 10)` is the quantity.

06

Repeated entry triggers repeat.

This effect is suitable for the demonstration of events. The formal play method can be recorded and only triggers the first entry of each player.

Creative extensions

Replace the chicken and it will become a new gameplay immediately.

This kind of program is suitable for the first Fabric event practice as a student, because it gives very fast feedback: to go into the world, to see results, to change codes, and then to enter the world. So much can be done with trigger timing and location calculations.

Animal welcome team:Several chickens, cows, and pigs are generated each to create a welcome scene into the world.
Reward block road:Generate diamond blocks, gold blocks, or custom blocks in front of the player to form a reward route.
Challenge opening:Generate several zombies or skeletons to create a "enter the world and start challenging immediately" mode.
Only trigger once:Use player data to record whether the welcome gift has been received to avoid a bunch of entities being generated every time you log in.

Chicken welcome

Fits for start-up learning entity generation, with cute results and low risks.

Cattle and sheep pasture

By increasing the quantity, you can make a mini ranch after the player enters the world.

Square pattern

Replace entities with blocks, and you can put out numbers, paths or customized block display stands.

What students learn

This is not a small isolated effect, but an entry to the Fabric event programming.

Read Events

Students will understand that code is not run randomly, but is called after a certain game event occurs.

Read Coordinates

Starting from the player position, forward direction, and lateral offset, establish a sense of space in the 3D world.

Read Extensions

Replacing the chicken with other entities or blocks means moving from "doing it" to "changing it yourself".

Consulting course arrangements View Mario MOD Tutorial

Into the world, there are 10 chickens.