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 attach="geometry" />
<meshStandardMaterial attach="material" 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 = false // Auto sRGBEncoding encoding for all colors and textures + ACESFilmic
vr = false // Switches renderer to VR mode, then uses gl.setAnimationLoop
gl2 = false // Enables webgl2
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 // You could provide window.devicePixelRatio if you like
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 target
You 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 }
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 attach="geometry" args={[1, 16, 16]} />
<meshStandardMaterial attach="material" color="hotpink" transparent />
</mesh>
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 take the same properties they normally would, constructor arguments are passed as an array via args
. If args change, later on, the object gets re-constructed from scratch! 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} />
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 multiples 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-fibers catalogue of JSX elements.
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')}
onPointerLeave={(e) => console.log('leave')}
onPointerMove={(e) => console.log('move')}
onUpdate={(self) => console.log('props have been updated')}
/>
({
...DomEvent // All the original event data
...ThreeEvent // All of Three's intersection data
intersections: Intersect[] // All intersections
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
}) => ...
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(): SharedCanvasContext
This 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)
viewport, // Bounds of the viewport in 3d units + factor (size/viewport)
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, // Invalidates a single frame (for <Canvas invalidateFrameloop />)
intersect, // Calls onMouseMove handlers for objects underneath the cursor
setDefaultCamera, // Sets the default camera
} = useThree()
useFrame((callback: (state, delta) => void), (renderPriority: number = 0))
This hook calls you back every frame, which is good for running effects, updating controls, etc. You receive the state (same as useThree) and a clock delta. If you supply a render priority greater than zero it will switch off automatic rendering entirely, you can then control rendering yourself. If you have multiple frames with a render priority then they are ordered highest priority last, similar to the web's z-index. Frames are managed, three-fiber will remove them automatically when the component that holds them is unmounted.
Updating controls:
import { useFrame } from 'react-three-fiber'
const controls = useRef()
useFrame((state) => controls.current.update())
return <orbitControls ref={controls} />
Taking over the render-loop:
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 resources across components.
import { useResource } from 'react-three-fiber'
const [ref, material] = useResource()
return (
<meshBasicMaterial ref={ref} />
{material && (
<mesh material={material} />
<mesh material={material} />
<mesh material={material} />
)}
)
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, url: string | string[], extensions?)
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} dispose={null} />
}
<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])
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
} 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:
const forwardContext = React.createContext()
function App() {
return (
<Canvas>
<forwardContext.Provider value={useContext(originalContext)}>
{/* children can now read state from forwardContext */}