import THREE from 'three'
/**
 * @author alteredq / http://alteredqualia.com/
 */

THREE.EffectComposer = function ( renderer, renderTarget ) {

  this.renderer = renderer;

  if ( renderTarget === undefined ) {

    var pixelRatio = renderer.getPixelRatio();

    var width  = Math.floor( renderer.context.canvas.width  / pixelRatio ) || 1;
    var height = Math.floor( renderer.context.canvas.height / pixelRatio ) || 1;
    var parameters = { minFilter: THREE.LinearFilter, magFilter: THREE.LinearFilter, format: THREE.RGBFormat, stencilBuffer: false };

    renderTarget = new THREE.WebGLRenderTarget( width, height, parameters );

  }

  this.renderTarget1 = renderTarget;
  this.renderTarget2 = renderTarget.clone();

  this.writeBuffer = this.renderTarget1;
  this.readBuffer = this.renderTarget2;

  this.passes = [];

  if ( THREE.CopyShader === undefined )
    console.error( "THREE.EffectComposer relies on THREE.CopyShader" );

  this.copyPass = new THREE.ShaderPass( THREE.CopyShader );

};

THREE.EffectComposer.prototype = {

  swapBuffers: function() {

    var tmp = this.readBuffer;
    this.readBuffer = this.writeBuffer;
    this.writeBuffer = tmp;

  },

  addPass: function ( pass ) {

    this.passes.push( pass );

  },

  insertPass: function ( pass, index ) {

    this.passes.splice( index, 0, pass );

  },

  render: function ( delta ) {

    this.writeBuffer = this.renderTarget1;
    this.readBuffer = this.renderTarget2;

    var maskActive = false;

    var pass, i, il = this.passes.length;

    for ( i = 0; i < il; i ++ ) {

      pass = this.passes[ i ];

      if ( !pass.enabled ) continue;

      pass.render( this.renderer, this.writeBuffer, this.readBuffer, delta, maskActive );

      if ( pass.needsSwap ) {

        if ( maskActive ) {

          var context = this.renderer.context;

          context.stencilFunc( context.NOTEQUAL, 1, 0xffffffff );

          this.copyPass.render( this.renderer, this.writeBuffer, this.readBuffer, delta );

          context.stencilFunc( context.EQUAL, 1, 0xffffffff );

        }

        this.swapBuffers();

      }

      if ( pass instanceof THREE.MaskPass ) {

        maskActive = true;

      } else if ( pass instanceof THREE.ClearMaskPass ) {

        maskActive = false;

      }

    }

  },

  reset: function ( renderTarget ) {

    if ( renderTarget === undefined ) {

      renderTarget = this.renderTarget1.clone();

      var pixelRatio = this.renderer.getPixelRatio();

      renderTarget.width  = Math.floor( this.renderer.context.canvas.width  / pixelRatio );
      renderTarget.height = Math.floor( this.renderer.context.canvas.height / pixelRatio );

    }

    this.renderTarget1 = renderTarget;
    this.renderTarget2 = renderTarget.clone();

    this.writeBuffer = this.renderTarget1;
    this.readBuffer = this.renderTarget2;

  },

  setSize: function ( width, height ) {

    var renderTarget = this.renderTarget1.clone();

    renderTarget.width = width;
    renderTarget.height = height;

    this.reset( renderTarget );

  }

};
export default THREE.EffectComposer;
