You need to be versed in both React and Threejs before rushing into this. If you are unsure about React consult the official React docs, especially the section about hooks. As for Threejs, make sure you at least glance over the fundamentals section on the main-page, know at least the very basics.
- Canvas
- Objects, properties and constructor arguments
- Automatic disposal
- Events
- Hooks
- Additional exports
- Gotchas
The Canvas object is your portal into Threejs. It renders Threejs elements, not DOM elements! Here is a small hello-world that you can try out:
import ReactDOM from 'react-dom'
import React from 'react'
import { Canvas } from 'react-three-fiber'
ReactDOM.render(
<Canvas>
<pointLight position={[10, 10, 10]} />
<mesh>
<sphereBufferGeometry />
<meshStandardMaterial color="hotpink" />
</mesh>
</Canvas>,
document.getElementById('root')
)The canvas stretches to 100% of the next relative/absolute parent-container. Make sure your canvas is given space to show contents!
<Canvas
children // Either a function child (which receives state) or regular children
gl // Props that go into the default webGL-renderer
camera // Props that go into the default camera
raycaster // Props that go into the default raycaster
shadowMap // Props that go into gl.shadowMap, can also be set true for PCFsoft
colorManagement = true // Auto sRGBEncoding encoding for all colors and textures + ACESFilmic
vr = false // Switches renderer to VR mode, then uses gl.setAnimationLoop
webgl1 = false // Forces THREE to WebGL1, instead of WebGL2 (default)
concurrent = false // Enables React concurrent mode
resize = undefined // Resize config, see react-use-measure's options
orthographic = false // Creates an orthographic camera if true
noEvents = false // Switch off raytracing and event support
pixelRatio = undefined // Default: 1. Use window.devicePixelRatio, or automatic: [min, max]
invalidateFrameloop = false // When true it only renders on changes, when false it's a game loop
updateDefaultCamera = true // Adjusts default camera on size changes
onCreated // Callback when vdom is ready (you can block first render via promise)
onPointerMissed /> // Response for pointer clicks that have missed a targetYou can give it additional properties like style and className, which will be added to the container (a div) that holds the dom-canvas element.
Canvas will create a translucent WebGL-renderer with the following properties:
- antialias=true
- alpha=true
- powerPreference="high-performance"
- setClearAlpha(0)
A default perspective camera: fov: 75, near: 0.1, far: 1000, z: 5, lookAt: [0,0,0]
A default orthographic camera if Canvas.orthographic is true: near: 0.1, far: 1000, z: 5, lookAt: [0,0,0]
A default shadowMap if Canvas.shadowMap is true: type: PCFSoftShadowMap
A default scene (into which all the JSX is rendered) and a raycaster.
A wrapping container with a resize observer: scroll: true, debounce: { scroll: 50, resize: 0 }. It does not polyfill it (see Safari support)
You do not have to use any of these objects, look under "Recipes" down below if you want to bring your own.
You can use Threejs's entire object catalogue and all properties. When in doubt, always consult the docs.
❌ You could lay out an object like this:
<mesh
visible
userData={{ hello: 'world' }}
position={new THREE.Vector3(1, 2, 3)}
rotation={new THREE.Euler(Math.PI / 2, 0, 0)}
geometry={new THREE.SphereGeometry(1, 16, 16)}
material={new THREE.MeshBasicMaterial({ color: new THREE.Color('hotpink'), transparent: true })}
/>✅ The problem is that all of these properties will always be re-created. Instead, you should define properties declaratively.
<mesh visible userData={{ hello: 'world' }} position={[1, 2, 3]} rotation={[Math.PI / 2, 0, 0]}>
<sphereGeometry args={[1, 16, 16]} />
<meshStandardMaterial color="hotpink" transparent />
</mesh>In threejs objects are classes that are instanciated. These classes can receive one-time constructor arguments (new THREE.SphereBufferGeometry(1, 32)), and properties (someObject.visible = true). In three-fiber constructor arguments are always passed as an array via args. If args change later on, the object must naturally get re-constructed from scratch!
<sphereBufferGeometry args={[1, 32]} />All properties whose underlying object has a .set() method can directly receive the same arguments that set would otherwise take. For example THREE.Color.set can take a color string, so instead of color={new THREE.Color('hotpink')} you can simply write color="hotpink". Some set methods take multiple arguments, for instance THREE.Vector3, give it an array in that case position={[100, 0, 0]}.
You can put non-Object3D primitives (geometries, materials, etc) into the render tree as well, so that they become managed and reactive. They are not part of the threejs scene! They take the same properties and constructor arguments they normally would.
Using the attach property objects bind to their parent and are taken off once they unmount.
You can nest primitive objects, too:
<mesh>
<meshBasicMaterial attach="material">
<texture attach="map" image={img} onUpdate={self => img && (self.needsUpdate = true)} />Sometimes attaching isn't enough. For example, the following example attaches effects to an array called "passes" of the parent effectComposer. Note the use of attachArray which adds the object to the target array and takes it out on unmount:
<effectComposer>
<renderPass attachArray="passes" scene={scene} camera={camera} />
<glitchPass attachArray="passes" renderToScreen />You can also attach to named parent properties using attachObject={[target, name]}, which adds the object and takes it out on unmount. The following adds a buffer-attribute to parent.attributes.position.
<bufferGeometry attach="geometry">
<bufferAttribute attachObject={['attributes', 'position']} count={v.length / 3} array={v} itemSize={3} />New in v5, all elements ending with "Material" receive attach="material", and all elements ending with "Geometry" receive attach="geometry" automatically. Of course you can still overwrite it, but it isn't necessary to type out any longer.
<mesh>
<meshBasicMaterial />
<boxBufferGeometry />If you want to reach into nested attributes (for instance: mesh.rotation.x), just use dash-case.
<mesh rotation-x={1} material-uniforms-resolution-value={[1 / size.width, 1 / size.height]} />You can use the primitive placeholder for that. You can still give it properties or attach nodes to it. Never add the same object multiple times, this is not allowed in Threejs!
const mesh = useMemo(() => new THREE.Mesh(), [])
return <primitive object={mesh} position={[0, 0, 0]} />The extend function extends three-fiber's catalogue of JSX elements. Components added this way can then be referenced in the scene-graph using camel casing similar to other primitives.
import { extend } from 'react-three-fiber'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls'
import { TransformControls } from 'three/examples/jsm/controls/TransformControls'
extend({ OrbitControls, TransformControls })
// ...
return (
<>
<orbitControls />
<transformControls />Freeing resources is a manual chore in Threejs, but React is aware of object-lifecycles, hence three-fiber will attempt to free resources for you by calling object.dispose(), if present, on all unmounted objects.
If you manage assets by yourself, globally or in a cache, this may not be what you want. You can switch it off by placing dispose={null} onto meshes, materials, etc, or even on parent containers like groups, it is now valid for the entire tree.
const globalGeometry = new THREE.BoxBufferGeometry()
const globalMaterial = new THREE.MeshBasicMaterial()
function Mesh() {
return (
<group dispose={null}>
<mesh geometry={globalGeometry} material={globalMaterial} />Threejs objects that implement their own raycast method (meshes, lines, etc) can be interacted with by declaring events on them. We support pointer events, clicks and wheel-scroll. Events contain the browser event as well as the Threejs event data (object, point, distance, etc). You need to polyfill them yourself, if that's a concern.
Additionally, there's a special onUpdate that is called every time the object gets fresh props, which is good for things like self => (self.verticesNeedUpdate = true).
Also notice the onPointerMissed on the canvas element, which fires on clicks that haven't hit any meshes.
<mesh
onClick={(e) => console.log('click')}
onContextMenu={(e) => console.log('context menu')}
onDoubleClick={(e) => console.log('double click')}
onWheel={(e) => console.log('wheel spins')}
onPointerUp={(e) => console.log('up')}
onPointerDown={(e) => console.log('down')}
onPointerOver={(e) => console.log('over')}
onPointerOut={(e) => console.log('out')}
onPointerEnter={(e) => console.log('enter')} // see note 1
onPointerLeave={(e) => console.log('leave')} // see note 1
onPointerMove={(e) => console.log('move')}
onPointerMissed={() => console.log('missed')}
onUpdate={(self) => console.log('props have been updated')}
/>({
...DomEvent // All the original event data
...Intersection // All of Three's intersection data - see note 2
intersections: Intersection[] // The first intersection of each intersected object
object: Object3D // The object that was actually hit
eventObject: Object3D // The object that registered the event
unprojectedPoint: Vector3 // Camera-unprojected point
ray: Ray // The ray that was used to strike the object
camera: Camera // The camera that was used in the raycaster
sourceEvent: DomEvent // A reference to the host event
delta: number // Initial-click delta
}) => ...How the event-system works, bubbling and capture
Note 1: the pointerenter and pointerleave events work exactly the same as pointerover and pointerout. The pointerenter and pointerleave semantics are not implemented.
Note 2: Some events (such as pointerout) happen when there is no intersection between eventObject and the ray. When this happens, the event will contain intersection data from a previous event with this object.
Propagation works a bit differently to the DOM because objects can occlude each other in 3D. The intersections array in the event includes all objects intersecting the ray, not just the nearest. Only the first intersection with each object is included.
The event is first delivered to the object nearest the camera, and then bubbles up through its ancestors like in the DOM. After that, it is delivered to the next nearest object, and then its ancestors, and so on. This means objects are transparent to pointer events by default, even if the object handles the event.
event.stopPropagation() doesn't just stop this event from bubbling up, it also stops it from being delivered to farther objects (objects behind this one). All other objects, nearer or farther, no longer count as being hit while the pointer is over this object. If they were previously delivered pointerover events, they will immediately be delivered pointerout events. If you want an object to block pointer events from objects behind it, it needs to have an event handler as follows:
onPointerOver={e => {
e.stopPropagation()
// ...
}}even if you don't want this object to respond to the pointer event. If you do want to handle the event as well as using stopPropagation(), remember that the pointerout events will happen during the stopPropagation() call. You probably want your other event handling to happen after this.
Because events go to all intersected objects, capturing the pointer also works differently. In the DOM, the capturing object replaces the hit test, but in React-Three-Fiber, the capturing object is added to the hit test result: if the capturing object was not hit, then all of the hit objects (and their ancestors) get the event first, followed by the capturing object and its ancestors. The capturing object can also use event.stopPropagation() so that objects that really were hit get pointerout events.
Note that you can access the setPointerCapture and releasePointerCapture methods only via event.target: they don't get added to the Object3D instances in the scene graph.
setPointerCapture and releasePointerCapture take a pointerId parameter like in the DOM, but for now they don't have support for multiple active pointers. PRs are welcome!
onPointerDown={e => {
// Only the mesh closest to the camera will be processed
e.stopPropagation()
// You may optionally capture the target
e.target.setPointerCapture(e.pointerId)
}}
onPointerUp={e => {
e.stopPropagation()
// Optionally release capture
e.target.releasePointerCapture(e.pointerId)
}}Hooks can only be used inside the Canvas element because they rely on context!
❌ You cannot expect something like this to work:
function App() {
const { size } = useThree() // This will just crash
return (
<Canvas>
<mesh>✅ Do this instead:
function SomeComponent() {
const { size } = useThree()
return <mesh />
}
function App() {
return (
<Canvas>
<SomeComponent />useThree(): SharedCanvasContextThis hook gives you access to all the basic objects that are kept internally, like the default renderer, scene, camera. It also gives you the current size of the canvas in screen and viewport coordinates. The hook is reactive, if you resize the browser, for instance, and you get fresh measurements, same applies to any of the defaults you can change.
import { useThree } from 'react-three-fiber'
const {
gl, // WebGL renderer
scene, // Default scene
camera, // Default camera
raycaster, // Default raycaster
size, // Bounds of the view (which stretches 100% and auto-adjusts)
aspect, // Aspect ratio (size.width / size.height)
mouse, // Current, centered, normalized 2D mouse coordinates
raycaster, // Internal raycaster instance
clock, // THREE.Clock (useful for useFrame deltas)
invalidate,
intersect,
setDefaultCamera,
viewport,
forceResize,
} = useThree()
// Reactive viewport bounds, will updated on resize
const { width, height, factor, distance } = viewport
// Viewport can also calculate precise bounds on demand!
const { width, height, factor, distance } = viewport(camera?: THREE.Camera, target?: THREE.Vector3)
// Flags the canvas as "dirty" and forces a single frame
// Use this to inform your canvas of changes when it is set to "invalidateFrameloop"
invalidate()
// Exchanges the default camera
setDefaultCamera(camera)
// Trigger an intersect/raycast as well as event handlers that may respond
intersect(optionalEvent?: PointerEvent)
// Force size/viewport recalculation
forceResize()useFrame((callback: (state, delta) => void), (renderPriority: number = 0))Allows you to execute code on every frame rendered, like running effects, updating controls, and so on. You receive the state (same as useThree) and a clock delta. Your callback function will be invoked just before a frame is rendered.
import { useFrame } from 'react-three-fiber'
const Controls = () => {
const controls = useRef()
/* Invoke the OrbitControls' update function on every frame */
useFrame(() => controls.current.update())
return <orbitControls ref={controls} />
}If you need more control over the order in which useFrame callbacks are executed (and frames are rendered), you may pass a numerical renderPriority value; callbacks will be executed in order of ascending priority values (lowest first, highest last.)
Using a non-zero render priority will cause react-three-fiber to disable its automatic rendering, and it will be your responsibility to render explicitly:
useFrame(({ gl, scene, camera }) => gl.render(scene, camera), 1)useResource((optionalRef = undefined))Take advantage of React's useRef with the added consideration of rendering when a component is available (e.g. in the next frame). Useful when you want to share and re-use declarative resources.
import { useResource } from 'react-three-fiber'
const material = useResource()
return (
<meshBasicMaterial ref={material} />
<mesh material={material.current} />
<mesh material={material.current} />
<mesh material={material.current} />
)useUpdate(callback, dependencies, (optionalRef = undefined))When objects need to be updated imperatively.
import { useUpdate } from 'react-three-fiber'
const ref = useUpdate(
(geometry) => {
geometry.addAttribute('position', getVertices(x, y, z))
geometry.attributes.position.needsUpdate = true
},
[x, y, z] // execute only if these properties change
)
return <bufferGeometry ref={ref} />useLoader(loader: THREE.Loader, url: string | string[], extensions?, xhr?)This hook loads assets and suspends for easier fallback- and error-handling.
import React, { Suspense } from 'react'
import { useLoader } from 'react-three-fiber'
import { GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader'
function Asset({ url }) {
const gltf = useLoader(GLTFLoader, url)
return <primitive object={gltf.scene} />
}
<Suspense fallback={<Cube />}>
<Asset url="/spaceship.gltf" />
</Suspense>You can provide a callback if you need to configure your loader:
import { DRACOLoader } from 'three/examples/jsm/loaders/DRACOLoader'
useLoader(GLTFLoader, url, (loader) => {
const dracoLoader = new DRACOLoader()
dracoLoader.setDecoderPath('/draco-gltf/')
loader.setDRACOLoader(dracoLoader)
})It can also make multiple requests in parallel:
const [bumpMap, specMap, normalMap] = useLoader(TextureLoader, [url1, url2, url2])Special treatment of GLTFLoaders and all loaders that return a `scene` props.
If a data.scene prop is found the hook will automatically create a named object/material collection: nodes and materials. You might want use more for finegrained control of the loader-data. It lets you build immutable scene graphs selectively. You can also specifically alter the data without having to traverse it. The gltfjsx specifically relies on this data.
const { nodes, material } = useLoader(GLTFLoader, url)const { nodes, materials } = useGraph(object: THREE.Object3D)Convenience hook which creates a memoized, named object/material collection from any Object3D.
function Asset({ url }) {
const scene = useLoader(OBJLoader, url)
const { nodes, materials } = useGraph(scene)
return <mesh geometry={nodes.robot.geometry} material={materials.metal} />import {
addEffect, // Adds a global render callback which is called each frame
addAfterEffect, // Adds a global after-render callback which is called each frame
addTail, // Adds a global callback which is called when rendering stops
invalidate, // Forces view global invalidation
extend, // Extends the native-object catalogue
createPortal, // Creates a portal (it's a React feature for re-parenting)
render, // Internal: Renders three jsx into a scene
unmountComponentAtNode, // Internal: Unmounts root scene
applyProps, // Internal: Sets element properties
forceResize, // Internal: Force size/viewport recalculation of all canvases
} from 'react-three-fiber'At the moment React context can not be readily used between two renderers, this is due to a problem within React. If react-dom opens up a provider, you will not be able to consume it within <Canvas>. If managing state (like Redux) is your problem, then zustand is likely the best solution, otherwise you can solve it by forwarding the context object that you are trying to access:
function App() {
const value = useContext(context)
return (
<Canvas>
<context.Provider value={value}>
{/* children can now read state from context */}