three.js/examples/jsm/postprocessing/BloomPass.js

import {
	AdditiveBlending,
	LinearFilter,
	RGBAFormat,
	ShaderMaterial,
	UniformsUtils,
	Vector2,
	WebGLRenderTarget
} from '../../../build/three.module.js';
import { Pass } from '../postprocessing/Pass.js';
import { CopyShader } from '../shaders/CopyShader.js';
import { ConvolutionShader } from '../shaders/ConvolutionShader.js';

var BloomPass = function ( strength, kernelSize, sigma, resolution ) {

	Pass.call( this );

	strength = ( strength !== undefined ) ? strength : 1;
	kernelSize = ( kernelSize !== undefined ) ? kernelSize : 25;
	sigma = ( sigma !== undefined ) ? sigma : 4.0;
	resolution = ( resolution !== undefined ) ? resolution : 256;

	// render targets

	var pars = { minFilter: LinearFilter, magFilter: LinearFilter, format: RGBAFormat };

	this.renderTargetX = new WebGLRenderTarget( resolution, resolution, pars );
	this.renderTargetX.texture.name = 'BloomPass.x';
	this.renderTargetY = new WebGLRenderTarget( resolution, resolution, pars );
	this.renderTargetY.texture.name = 'BloomPass.y';

	// copy material

	if ( CopyShader === undefined )
		console.error( 'THREE.BloomPass relies on CopyShader' );

	var copyShader = CopyShader;

	this.copyUniforms = UniformsUtils.clone( copyShader.uniforms );

	this.copyUniforms[ 'opacity' ].value = strength;

	this.materialCopy = new ShaderMaterial( {

		uniforms: this.copyUniforms,
		vertexShader: copyShader.vertexShader,
		fragmentShader: copyShader.fragmentShader,
		blending: AdditiveBlending,
		transparent: true

	} );

	// convolution material

	if ( ConvolutionShader === undefined )
		console.error( 'THREE.BloomPass relies on ConvolutionShader' );

	var convolutionShader = ConvolutionShader;

	this.convolutionUniforms = UniformsUtils.clone( convolutionShader.uniforms );

	this.convolutionUniforms[ 'uImageIncrement' ].value = BloomPass.blurX;
	this.convolutionUniforms[ 'cKernel' ].value = ConvolutionShader.buildKernel( sigma );

	this.materialConvolution = new ShaderMaterial( {

		uniforms: this.convolutionUniforms,
		vertexShader: convolutionShader.vertexShader,
		fragmentShader: convolutionShader.fragmentShader,
		defines: {
			'KERNEL_SIZE_FLOAT': kernelSize.toFixed( 1 ),
			'KERNEL_SIZE_INT': kernelSize.toFixed( 0 )
		}

	} );

	this.needsSwap = false;

	this.fsQuad = new Pass.FullScreenQuad( null );

};

BloomPass.prototype = Object.assign( Object.create( Pass.prototype ), {

	constructor: BloomPass,

	render: function ( renderer, writeBuffer, readBuffer, deltaTime, maskActive ) {

		if ( maskActive ) renderer.state.buffers.stencil.setTest( false );

		// Render quad with blured scene into texture (convolution pass 1)

		this.fsQuad.material = this.materialConvolution;

		this.convolutionUniforms[ 'tDiffuse' ].value = readBuffer.texture;
		this.convolutionUniforms[ 'uImageIncrement' ].value = BloomPass.blurX;

		renderer.setRenderTarget( this.renderTargetX );
		renderer.clear();
		this.fsQuad.render( renderer );


		// Render quad with blured scene into texture (convolution pass 2)

		this.convolutionUniforms[ 'tDiffuse' ].value = this.renderTargetX.texture;
		this.convolutionUniforms[ 'uImageIncrement' ].value = BloomPass.blurY;

		renderer.setRenderTarget( this.renderTargetY );
		renderer.clear();
		this.fsQuad.render( renderer );

		// Render original scene with superimposed blur to texture

		this.fsQuad.material = this.materialCopy;

		this.copyUniforms[ 'tDiffuse' ].value = this.renderTargetY.texture;

		if ( maskActive ) renderer.state.buffers.stencil.setTest( true );

		renderer.setRenderTarget( readBuffer );
		if ( this.clear ) renderer.clear();
		this.fsQuad.render( renderer );

	}

} );

BloomPass.blurX = new Vector2( 0.001953125, 0.0 );
BloomPass.blurY = new Vector2( 0.0, 0.001953125 );

export { BloomPass };