You've learned the fundamentals of Three.js, built some exciting 3D scenes, and now it's time to elevate your creations to the next level. This section dives into the world of post-processing, a powerful technique that allows you to apply visual filters and effects to your entire rendered scene, much like photo editing for your 3D worlds. We'll explore how to implement common post-processing effects like Bloom, Depth of Field, and more, transforming static renders into dynamic and visually rich experiences.
Post-processing in Three.js typically involves rendering your scene to an offscreen buffer (a WebGLRenderTarget) and then rendering that buffer to the screen using a shader. This shader can then apply various effects. The EffectComposer in Three.js simplifies this process significantly, managing the render targets and applying effects in a chain.
import { WebGLRenderer, Scene, PerspectiveCamera } from 'three';
import { EffectComposer } from 'three/examples/jsm/postprocessing/EffectComposer.js';
import { RenderPass } from 'three/examples/jsm/postprocessing/RenderPass.js';
// ... setup renderer, scene, camera ...
const composer = new EffectComposer(renderer);
composer.addPass(new RenderPass(scene, camera));
// Add your post-processing passes here...
function animate() {
requestAnimationFrame(animate);
composer.render();
}The EffectComposer takes your renderer, scene, and camera. We first add a RenderPass, which is the essential step of rendering your actual scene to an intermediate texture. After that, you can chain other post-processing passes.
Bloom is a visual effect that simulates the way bright light can scatter and glow in real-world photography. It makes bright areas of your scene appear to 'bleed' light into surrounding darker areas, adding a sense of ethereal glow. In Three.js, this is often achieved by rendering bright pixels to a separate texture and then blurring and compositing them back onto the original image.