Code a Minecraft Clone Using React and Three.js

Bybomber bot

Building a Minecraft clone is an amazing way to level up your skills with React and 3D graphics while creating an interactive game you can show off to friends. In this in-depth guide, we‘ll walk through the process of coding a Minecraft-style voxel game using React and Three.js.

By the end, you‘ll have a fully playable game with core Minecraft features like a procedurally generated world, multiple block types, and the ability to place and break blocks. More importantly, you‘ll gain practical experience with essential web development concepts and a powerful 3D graphics library.

Let‘s get started by previewing the technologies we‘ll use and the game architecture.

Overview of the Tech Stack

At the core of our Minecraft clone is React, a popular JavaScript library for building user interfaces. React will handle the game‘s state management and UI rendering.

For the 3D graphics, we‘ll use Three.js, a powerful library that allows us to create and display 3D computer graphics in the browser. Three.js abstracts away many low-level details of 3D rendering and provides a more developer-friendly API.

We‘ll also leverage React hooks, a feature introduced in React 16.8 that allows us to manage state and lifecycle methods in functional components. Hooks like useState, useEffect, and useRef will help keep our code concise and readable.

Here‘s a high-level diagram of how the pieces fit together:

[Diagram showing React managing game state and UI, Three.js handling 3D rendering, and the two libraries communicating via hooks and refs]

With the basic architecture in mind, let‘s dive into building the game step-by-step.

Setting Up the Project

First, make sure you have Node.js installed. Then create a new React project using Create React App:

npx create-react-app minecraft-clone
cd minecraft-clone

Next, install Three.js and any necessary helper libraries:

npm install three @react-three/fiber @react-three/drei

@react-three/fiber provides a way to use Three.js in React, while @react-three/drei offers some useful helpers and abstractions.

With the basic project setup, we can start implementing the game.

Creating the Sky and Ground

Let‘s begin by setting up a Three.js scene with a sky and ground. In React, we can define 3D objects inside functional components:

import { Canvas } from ‘@react-three/fiber‘;
import { Sky } from ‘@react-three/drei‘;

function Ground() {
  return (
    <mesh position={[0, 0, 0]} rotation={[-Math.PI / 2, 0, 0]}>
      <planeGeometry args={[100, 100]} />
      <meshStandardMaterial color="green" />
    </mesh>
  );
}

function App() {
  return (
    <Canvas>
      <Sky />
      <Ground />
      <ambientLight intensity={0.5} />
      <directionalLight position={[1, 1, 1]} />
    </Canvas>
  );
}

export default App;

Here we define Ground as a plane geometry with a green material. The Canvas component sets up a Three.js scene where we add the Sky, Ground, and some basic lighting.

[Screenshot of the sky and ground rendering in the game]

Loading and Applying Textures

To give our game a Minecraft look, we‘ll use pixel art textures. Create a textures directory in your project and add texture files for different block types (e.g. grass.png, dirt.png, stone.png).

We can load and apply these textures to our 3D objects using Three.js‘s TextureLoader:

import { TextureLoader } from ‘three‘;
import { useLoader } from ‘@react-three/fiber‘;
import grassTexture from ‘./textures/grass.png‘;

function Ground() {
  const texture = useLoader(TextureLoader, grassTexture);

  return (
    <mesh position={[0, 0, 0]} rotation={[-Math.PI / 2, 0, 0]}>
      <planeGeometry args={[100, 100]} />
      <meshStandardMaterial map={texture} />
    </mesh>
  );
}

The useLoader hook asynchronously loads the texture, which we can then pass to the meshStandardMaterial‘s map prop.

[Screenshot showing the ground with a grass texture applied]

Implementing Player Movement and Camera

Next up is adding a player that can move around the world with a first-person camera. We‘ll use React hooks to manage the player‘s state and handle keyboard input:

import { useFrame, useThree } from ‘@react-three/fiber‘;
import { useSphere } from ‘@react-three/cannon‘;
import { useEffect, useRef } from ‘react‘;
import { Vector3 } from ‘three‘;

function Player() {
  const { camera } = useThree();
  const [ref, api] = useSphere(() => ({
    mass: 1,
    type: ‘Dynamic‘,
    position: [0, 1, 0],
  }));

  const velocity = useRef([0, 0, 0]);
  useEffect(() => {
    api.velocity.subscribe((v) => (velocity.current = v));
  }, []);

  const pos = useRef([0, 0, 0]);
  useEffect(() => {
    api.position.subscribe((p) => (pos.current = p));
  }, []);

  useFrame(() => {
    camera.position.copy(new Vector3(pos.current[0], pos.current[1], pos.current[2]));
    const direction = new Vector3();

    const frontVector = new Vector3(
      0,
      0,
      (moveBackward ? 1 : 0) - (moveForward ? 1 : 0)
    );
    const sideVector = new Vector3(
      (moveLeft ? 1 : 0) - (moveRight ? 1 : 0),
      0,
      0
    );

    direction
      .subVectors(frontVector, sideVector)
      .normalize()
      .multiplyScalar(SPEED)
      .applyEuler(camera.rotation);

    api.velocity.set(direction.x, velocity.current[1], direction.z);
  });

  return <mesh ref={ref} />;
}

This code defines a sphere collider for the player using @react-three/cannon. We subscribe to the player‘s velocity and position and update the camera‘s position on each frame.

The useFrame callback also checks for currently pressed keys and calculates a movement direction vector. This gets applied to the player‘s velocity so they move forward, backward, left or right.

[GIF showing the player moving around the world]

Managing Game State with React Hooks

To track the game‘s state (e.g. player position, block positions, selected block type), we‘ll use React‘s useState hook:

import { useState } from ‘react‘;

function App() {
  const [blocks, setBlocks] = useState([]);
  const [selectedBlockType, setSelectedBlockType] = useState(‘grass‘);

  // ...

  return (
    <>
      <Canvas>
        {/* ... */}
        <Cubes blocks={blocks} />
      </Canvas>
      <UI
        selectedBlockType={selectedBlockType}
        onBlockTypeSelect={setSelectedBlockType}
      />
    </>
  );
}

The blocks state is an array containing the position and type of each block in the world. selectedBlockType tracks the currently selected block type.

We pass the blocks state down to a Cubes component that renders each block, and the selectedBlockType state to a UI component with buttons for choosing the block type.

Adding Interaction: Placing and Breaking Blocks

To allow players to place and break blocks, we can use Three.js‘s raycasting to detect clicks on the terrain:

function Cubes({ blocks, addBlock, removeBlock }) {
  const { camera } = useThree();
  const [raycaster] = useState(() => new Raycaster());
  const [mousePos] = useState(() => new Vector2());

  useEffect(() => {
    const handleMouseMove = (event) => {
      mousePos.x = (event.clientX / window.innerWidth) * 2 - 1;
      mousePos.y = -(event.clientY / window.innerHeight) * 2 + 1;
    };

    const handleMouseClick = () => {
      raycaster.setFromCamera(mousePos, camera);
      const intersects = raycaster.intersectObjects(scene.children);

      if (intersects.length > 0) {
        const clickedBlock = intersects[0].object;
        const blockPosition = clickedBlock.position.clone().floor();

        if (event.altKey) {
          removeBlock(blockPosition);
        } else {
          const adjacentPosition = blockPosition.clone().add(intersects[0].face.normal);
          addBlock(adjacentPosition);
        }
      }
    };

    window.addEventListener(‘mousemove‘, handleMouseMove);
    window.addEventListener(‘click‘, handleMouseClick);

    return () => {
      window.removeEventListener(‘mousemove‘, handleMouseMove);
      window.removeEventListener(‘click‘, handleMouseClick); 
    };
  }, []);

  return (
    <group>
      {blocks.map(({ key, position, type }) => (
        <Cube key={key} position={position} type={type} />
      ))}
    </group>
  );
}

On each click, we use raycasting to find the clicked block. If the Alt key was pressed, we call removeBlock with the block‘s position. Otherwise, we call addBlock with the adjacent position to place a new block.

The addBlock and removeBlock functions update the blocks state, triggering a re-render of the Cubes component.

[GIF demonstrating placing and breaking blocks]

Saving and Loading the Game World

To persist the game world between sessions, we can save the blocks state to local storage and load it on startup:

function App() {
  const [blocks, setBlocks] = useState(() => {
    const savedBlocks = localStorage.getItem(‘blocks‘);
    return savedBlocks ? JSON.parse(savedBlocks) : [];
  });

  useEffect(() => {
    localStorage.setItem(‘blocks‘, JSON.stringify(blocks));
  }, [blocks]);

  // ...
}

We initialize the blocks state with any saved blocks from local storage. Whenever blocks changes, we save it back to local storage.

Optimizing Performance and Expanding the Game

As our Minecraft clone grows, there are a few ways we can optimize performance:

  • Render only visible chunks: Break the world into chunks and only render those within the camera‘s view frustum.
  • Use instanced rendering: If many blocks share the same geometry and material, we can render them more efficiently using Three.js‘s InstancedMesh.
  • Implement level of detail: Render distant chunks at a lower resolution to reduce the number of polygons.

We can also expand the game with more Minecraft-like features:

  • More block types and crafting recipes
  • Procedurally generated terrain with biomes
  • Hostile mobs and combat
  • Multiplayer support
[Screenshot or GIF teasing an expanded version of the game]

Conclusion

Congratulations! You‘ve built a functional Minecraft clone using React and Three.js.

In the process, you learned how to:

  • Set up a 3D scene with lighting and textures
  • Implement player movement and a first-person camera
  • Manage game state with React hooks
  • Handle user interaction to place and break blocks
  • Optimize rendering performance

I hope this guide has sparked your interest in React and Three.js game development. The techniques covered here – 3D rendering, state management, game loops – form a solid foundation you can build upon to create even more ambitious games.

Remember, game development is a continuous learning process. Keep experimenting, add your own creative touches, and most importantly, have fun!

Happy coding!

Further Resources

Here are some resources to dive deeper into React and Three.js game development:

You can also find the complete source code for this Minecraft clone on GitHub: [link to GitHub repo]

Feel free to reach out if you have any questions or want to share your own creations. Happy building!

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