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

class BloomPass extends Pass {

	constructor( strength = 1, kernelSize = 25, sigma = 4, resolution = 256 ) {

		super();

		// render targets

		const 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' );

		const 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' );

		const 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 FullScreenQuad( null );

	}

	render( 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 };