postfx-bloom

Post-Processing Bloom

Bloom effects using UnrealBloomPass for luminance-based glow and selective object bloom.

Quick Start

npm install three @react-three/fiber @react-three/postprocessing

import { Canvas } from '@react-three/fiber';
import { EffectComposer, Bloom } from '@react-three/postprocessing';

function Scene() {
  return (
    <Canvas>
      <mesh>
        <sphereGeometry args={[1, 32, 32]} />
        <meshStandardMaterial emissive="#00F5FF" emissiveIntensity={2} />
      </mesh>

      <EffectComposer>
        <Bloom
          luminanceThreshold={0.2}
          luminanceSmoothing={0.9}
          intensity={1.5}
        />
      </EffectComposer>
    </Canvas>
  );
}

Core Concepts

How Bloom Works

1. Threshold — Pixels brighter than threshold are extracted
2. Blur — Extracted pixels are blurred in multiple passes
3. Composite — Blurred result is added back to original image

Key Parameters

Parameter	Range	Description
luminanceThreshold	0-1	Brightness cutoff for bloom (lower = more glow)
luminanceSmoothing	0-1	Softness of threshold transition
intensity	0-10	Bloom brightness multiplier
radius	0-1	Blur spread/size
levels	1-9	Blur quality/iterations

Patterns

Cosmic Glow Effect

import { EffectComposer, Bloom } from '@react-three/postprocessing';
import { KernelSize } from 'postprocessing';

function CosmicBloom() {
  return (
    <EffectComposer>
      <Bloom
        luminanceThreshold={0.1}
        luminanceSmoothing={0.9}
        intensity={2.5}
        radius={0.8}
        kernelSize={KernelSize.LARGE}
        mipmapBlur
      />
    </EffectComposer>
  );
}

Neon Cyberpunk Bloom

// High-contrast neon with sharp falloff
function NeonBloom() {
  return (
    <EffectComposer>
      <Bloom
        luminanceThreshold={0.4}
        luminanceSmoothing={0.2}
        intensity={3.0}
        radius={0.4}
        mipmapBlur
      />
    </EffectComposer>
  );
}

// Emissive material for neon objects
function NeonTube({ color = '#FF00FF' }) {
  return (
    <mesh>
      <cylinderGeometry args={[0.05, 0.05, 2]} />
      <meshStandardMaterial
        emissive={color}
        emissiveIntensity={4}
        toneMapped={false}
      />
    </mesh>
  );
}