渲染时暂停，但当我使用react-三纤维中的useLoader时没有指定后备UI

Question

我正在尝试将纹理用于我的 ThreeJS 对象。我收到错误：

index.js:1 Error: Earth suspended while rendering, but no fallback UI was specified.

Add a <Suspense fallback=...> component higher in the tree to provide a loading indicator or placeholder to display.
    in Earth

地球.js：

export const Earth = () => {
    const texture = useLoader(THREE.TextureLoader, earthImg)

    return (
        <Suspense fallback={<h1>Loading profile...</h1>}>
            <mesh>
                <sphereBufferGeometry attach="geometry" args={[5, 32, 32]} />
                <meshStandardMaterial attach="material"  roughness={1} fog={false} />
            </mesh>
        </Suspense>
    )
}

索引.js：

export default function App() {
    return (
        <Canvas
            style={{height:'100vh',width:'100vw'}}
            camera={{
                position: [0, window.innerWidth / window.innerHeight, 5]
            }}
        >
            <ambientLight intensity={0.5} />
            <spotLight position={[10, 10, 10]} angle={0.15} penumbra={1} />
            <pointLight position={[-10, -10, -10]} />
            <Earth position={[-1.2, 0, 0]} />
        </Canvas>
    )
}

Answer 1

useLoader()调用的组件（<Earth>在本例中）需要包装在 a 中<Suspense>，不能从组件内指定暂挂回退。

地球.js：

export const Earth = () => {
    const texture = useLoader(THREE.TextureLoader, earthImg)

    return (
        <mesh>
            <sphereBufferGeometry attach="geometry" args={[5, 32, 32]} />
            <meshStandardMaterial attach="material"  roughness={1} fog={false} />
        </mesh>
    )
}

索引.js：

export default function App() {
    return (
        <Canvas
            style={{height:'100vh',width:'100vw'}}
            camera={{
                position: [0, window.innerWidth / window.innerHeight, 5]
            }}
        >
            <ambientLight intensity={0.5} />
            <spotLight position={[10, 10, 10]} angle={0.15} penumbra={1} />
            <pointLight position={[-10, -10, -10]} />
            <Suspense fallback={<h1>Loading profile...</h1>}>
                <Earth position={[-1.2, 0, 0]} />
            </Suspense>
        </Canvas>
    )
}