/**
 * @author alteredq / http://alteredqualia.com/
 */

THREE.ShaderPass = function ( shader, textureID ) {

    THREE.Pass.call( this );

    this.textureID = ( textureID !== undefined ) ? textureID : "tDiffuse";

    if ( shader instanceof THREE.ShaderMaterial ) {

        this.uniforms = shader.uniforms;

        this.material = shader;

    } else if ( shader ) {

        this.uniforms = THREE.UniformsUtils.clone( shader.uniforms );

        this.material = new THREE.ShaderMaterial( {

            defines: Object.assign( {}, shader.defines ),
            uniforms: this.uniforms,
            vertexShader: shader.vertexShader,
            fragmentShader: shader.fragmentShader

        } );

    }

    this.fsQuad = new THREE.Pass.FullScreenQuad( this.material );
};

THREE.ShaderPass.prototype = Object.assign( Object.create( THREE.Pass.prototype ), {

    constructor: THREE.ShaderPass,

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

        if ( this.uniforms[ this.textureID ] ) {

            this.uniforms[ this.textureID ].value = readBuffer.texture;

        }

        this.fsQuad.material = this.material;

        if ( this.renderToScreen ) {

            renderer.setRenderTarget( null );
            this.fsQuad.render( renderer );

        } else {

            renderer.setRenderTarget( writeBuffer );
            // TODO: Avoid using autoClear properties, see https://github.com/mrdoob/three.js/pull/15571#issuecomment-465669600
            if ( this.clear ) renderer.clear( renderer.autoClearColor, renderer.autoClearDepth, renderer.autoClearStencil );
            this.fsQuad.render( renderer );

        }

    }

} );