Textures and Lighting with React and Three.js
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In my previous three posts, I have developed a simple WebGL application using react-three-fiber and three.js. In this post, I am adding texture loading and proper lighting to the application.
For reference, here the links to the previous versions of the app:
- Version 1: Just being able to drag a shape on the screen
- Version 2: Dragging and dropping shapes using physics
- Version 3: Being able to move the camera
Here the version developed for this post:
You can click to add objects, click and drag them as well as move the camera using WASD keys and mouse wheel to zoom.
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Loading Textures
Textures can be loaded easily in react-three-fiber using the useResource
hook.
All that is required to place the texture in the public/
folder of the react application, load the texture and then link it to the material by setting the map
property.
const [texture] = useLoader(TextureLoader, 'textures/grasslight-big.jpg');
if (texture) {
texture.wrapS = texture.wrapT = THREE.RepeatWrapping;
texture.repeat.set(1500, 1500);
texture.anisotropy = 16;
}
return (
<mesh ref={ref} receiveShadow position={position} onClick={onPlaneClick}>
<planeBufferGeometry attach="geometry" args={[10000, 10000]} />
{texture && <meshPhongMaterial attach="material" map={texture} />}
</mesh>
);
I found that textures are often quite large in size; larger than 1 MB. This significantly extends loading times. Thus I have added a simple loading screen. Unfortunately to be able to display the text 'loading' I had to create a TextGeometry which in turn required a font to be loaded (I prepared the Roboto font using facetype.js. This font by itself is more than 300 kb, so even loading the loading screen takes a bit of time.
Lighting
The goal of this application is to have a simple, very large plane on which any number of objects may be added. The issue I encountered with this was that to get shadows working with a DirectionalLight turned out to be very tricky. In the end, I used a combination of an AmbientLight with a SpotLight.
<ambientLight intensity={0.9} />
<primitive object={lightTarget} position={lightTargetPosition} />
<spotLight
castShadow
intensity={0.25}
position={lightPosition}
angle={Math.PI / 3}
penumbra={1}
shadow-mapSize={new Vector2(2048 * 5, 2048 * 5)}
target={lightTarget}
/>
Since the SpotLight would not be able to cover the whole of the plane (as said, it is meant to be very large) and provide accurate shadows, I opted for moving the SpotLight when a user moves the camera.
const lightTargetYDelta = 120;
const lightTargetXDelta = 80;
const [lightPosition, setLightPosition] = useState([
-lightTargetXDelta,
-lightTargetYDelta,
200,
]);
const [lightTargetPosition, setLightTargetPosition] = useState([0, 0, 0]);
const onCameraMoved = (delta) => {
const newLightPosition = delta.map((e, idx) => lightPosition[idx] + e);
setLightPosition(newLightPosition);
const newLightTargetPosition = [
newLightPosition[0] + lightTargetXDelta,
newLightPosition[1] + lightTargetYDelta,
0,
];
setLightTargetPosition(newLightTargetPosition);
};
This required both updating the position of the light setLightPosition
as well as moving the light target setLightTargetPosition
.
Modularity
Since the amount of code for this example increased quite a bit over the past three iterations, I broke up the application into multiple modules, with most React components now sitting in their own file.
I think this really shows the advantage of using React with Three.js, since it is easy for each component to manage its own state.
For the next iteration, I will most likely be looking at how I can remove the textures or use much smaller textures. I would like the application to be able to load as quickly as possible, and textures clearly do not seem a great option for this.