three.js/examples/js/postprocessing/MSAAPass.js

/**
 * @author bhouston / http://clara.io/
 */

THREE.MSAAPass = function ( scene, camera, params, clearColor, clearAlpha ) {

  this.scene = scene;
  this.camera = camera;

  // any set of samples in equal area weighting pattern is fine (3 or +4 samples would also work as well)
  this.sampleOffsets = [];
  this.sampleOffsets[0] = null;
  this.sampleOffsets[1] = this.standardDirctX11_MSAA2();
  this.sampleOffsets[2] = this.standardDirctX11_MSAA4();
  this.sampleOffsets[3] = this.standardDirctX11_MSAA8();
  this.sampleOffsets[4] = this.standardDirctX11_MSAA16();
  this.sampleOffsets[5] = this.standardDirctX11_MSAA32();

  this.currentSampleLevel = 4;

  this.params = params || { minFilter: THREE.NearestFilter, magFilter: THREE.NearestFilter, format: THREE.RGBAFormat };
  this.params.minFilter = THREE.NearestFilter;
  this.params.maxFilter = THREE.NearestFilter;

  this.clearColor = clearColor;
  this.clearAlpha = ( clearAlpha !== undefined ) ? clearAlpha : 1;

  this.oldClearColor = new THREE.Color();
  this.oldClearAlpha = 1;

  this.enabled = true;
  this.clear = false;
  this.needsSwap = true;

  var msaaShader = THREE.MSAA4Shader;
  this.uniforms = THREE.UniformsUtils.clone( msaaShader.uniforms );

  this.materialMSAA = new THREE.ShaderMaterial({
    shaderID: msaaShader.shaderID,
    uniforms: this.uniforms,
    vertexShader: msaaShader.vertexShader,
    fragmentShader: msaaShader.fragmentShader,
    transparent: true,
    blending: THREE.CustomBlending,
    blendSrc: THREE.OneFactor,
    blendDst: THREE.OneFactor,
    blendEquation: THREE.AddEquation,
    depthTest: false,
    depthWrite: false
  });

  this.camera2 = new THREE.OrthographicCamera( -1, 1, 1, -1, 0, 1 );
  this.scene2  = new THREE.Scene();

  this.quad2 = new THREE.Mesh( new THREE.PlaneGeometry( 2, 2 ), null );
  this.scene2.add( this.quad2 );

  this.devicePixelRatio = 1;

};

THREE.MSAAPass.prototype = {

  dispose: function() {

    if( this.renderTargets ) {
      for( var i = 0; i < this.renderTargets.length; i ++ ) {
        this.renderTargets[i].dispose();
      }
      this.renderTargets = null;
    }

  },

  render: function ( renderer, writeBuffer, readBuffer, delta ) {

    if( ! this.renderTargets ) {
      this.renderTargets = [];
      for( var i = 0; i < 2; i ++ ) {
        this.renderTargets.push( new THREE.WebGLRenderTarget( readBuffer.width, readBuffer.height, this.params, "msaa.renderTarget" + i ) );
      }
    }

    var camera = ( this.camera || this.scene.camera );

    var currentSampleOffsets = this.sampleOffsets[ Math.max( 0, Math.min( this.currentSampleLevel, 5 ) ) ];

    if( ! currentSampleOffsets ) {

      renderer.render( this.scene, camera, this.renderTargets[0], true );

      this.uniforms[ "tBackground" ].value = readBuffer;
      this.uniforms[ "scale" ].value = 1.0;
      for( var k = 0; k < this.renderTargets.length; k ++ ) {
        this.uniforms[ "tSample" + k ].value = this.renderTargets[0];
      }
      this.quad2.material = this.materialMSAA;

      renderer.render( this.scene2, this.camera2, writeBuffer, true );

      return;
    }

    this.scene.overrideMaterial = null;

    this.oldClearColor.copy( renderer.getClearColor() );
    this.oldClearAlpha = renderer.getClearAlpha();

    renderer.setClearColor( new THREE.Color( 0, 0, 0 ), 0 );

    for( var j = 0; j < currentSampleOffsets.length; j += this.renderTargets.length ) {

      this.uniforms[ "tBackground" ].value = readBuffer;
      this.uniforms[ "scale" ].value = 1.0 / currentSampleOffsets.length;
      for( var k = 0; k < this.renderTargets.length; k ++ ) {
        this.uniforms[ "tSample" + k ].value = this.renderTargets[k];
      }
      this.quad2.material = this.materialMSAA;

      for( var k = 0; k < Math.min( currentSampleOffsets.length - j, this.renderTargets.length ); k ++ ) {
        var i = j + k;

        if( camera.setViewOffset ) {

          camera.setViewOffset( readBuffer.width, readBuffer.height, currentSampleOffsets[i].x, currentSampleOffsets[i].y, readBuffer.width, readBuffer.height );

        }

        renderer.render( this.scene, camera, this.renderTargets[k], true );

      }

      renderer.render( this.scene2, this.camera2, writeBuffer, j === 0 );

    }

    camera.fullWidth = undefined;
    camera.fullHeight = undefined;
    camera.x = undefined;
    camera.y = undefined;
    camera.width = undefined;
    camera.height = undefined;
    camera.updateProjectionMatrix();

    renderer.setClearColor( this.oldClearColor, this.oldClearAlpha );

  },

  // DirectX 11 standard MSAA sample pattern
  standardDirctX11_MSAA2: function() {
    var vectors = [
      new THREE.Vector3(  4,  4, 0 ),
      new THREE.Vector3( -4, -4, 0 )
    ];
    var xfrm = new THREE.Matrix4().makeScale( 1 / 16.0, 1/ 16.0, 0 );
    var vectors2 = [];
    for( var i = 0; i < vectors.length; i ++ ) {
      vectors2.push( vectors[i].clone().applyMatrix4( xfrm ) );
    }
    return vectors2;
  },

  // DirectX 11 standard MSAA sample pattern
  standardDirctX11_MSAA4: function() {
    var vectors = [
      new THREE.Vector3( -2, -6, 0 ),
      new THREE.Vector3(  6, -2, 0 ),
      new THREE.Vector3( -6,  2, 0 ),
      new THREE.Vector3(  2,  6, 0 )
    ];
    var xfrm = new THREE.Matrix4().makeScale( 1 / 16.0, 1/ 16.0, 0 );
    var vectors2 = [];
    for( var i = 0; i < vectors.length; i ++ ) {
      vectors2.push( vectors[i].clone().applyMatrix4( xfrm ) );
    }
    return vectors2;
  },

  // DirectX 11 standard MSAA sample pattern
  standardDirctX11_MSAA8: function() {
    var vectors = [
      new THREE.Vector3(  1, -3, 0 ),
      new THREE.Vector3( -1,  3, 0 ),
      new THREE.Vector3(  5,  1, 0 ),
      new THREE.Vector3( -3, -5, 0 ),
      new THREE.Vector3( -5,  5, 0 ),
      new THREE.Vector3( -7, -1, 0 ),
      new THREE.Vector3(  3,  7, 0 ),
      new THREE.Vector3(  7, -7, 0 ),
    ];
    var xfrm = new THREE.Matrix4().makeScale( 1 / 16.0, 1/ 16.0, 0 );
    var vectors2 = [];
    for( var i = 0; i < vectors.length; i ++ ) {
      vectors2.push( vectors[i].clone().applyMatrix4( xfrm ) );
    }
    return vectors2;
  },

  // DirectX 11 standard MSAA sample pattern
  standardDirctX11_MSAA16: function() {
    var vectors = [
      new THREE.Vector3(  1,  1, 0 ),
      new THREE.Vector3( -1, -3, 0 ),
      new THREE.Vector3( -3,  2, 0 ),
      new THREE.Vector3(  4, -1, 0 ),

      new THREE.Vector3( -5, -2, 0 ),
      new THREE.Vector3(  2,  5, 0 ),
      new THREE.Vector3(  5,  3, 0 ),
      new THREE.Vector3(  3, -5, 0 ),

      new THREE.Vector3( -2,  6, 0 ),
      new THREE.Vector3(  0, -7, 0 ),
      new THREE.Vector3( -4, -6, 0 ),
      new THREE.Vector3( -6,  4, 0 ),

      new THREE.Vector3( -8,  0, 0 ),
      new THREE.Vector3(  7, -4, 0 ),
      new THREE.Vector3(  6,  7, 0 ),
      new THREE.Vector3( -7, -8, 0 ),
    ];
    var xfrm = new THREE.Matrix4().makeScale( 1 / 16.0, 1/ 16.0, 0 );
    var vectors2 = [];
    for( var i = 0; i < vectors.length; i ++ ) {
      vectors2.push( vectors[i].clone().applyMatrix4( xfrm ) );
    }
    return vectors2;
  },

  // based on this: http://images.anandtech.com/reviews/video/NVIDIA/GF100/CSAA.png
  standardDirctX11_MSAA32: function() {
    var vectors = [
      new THREE.Vector3( -4, -7, 0 ),
      new THREE.Vector3( -7, -5, 0 ),
      new THREE.Vector3( -3, -5, 0 ),
      new THREE.Vector3( -5, -4, 0 ),

      new THREE.Vector3( -1, -4, 0 ),
      new THREE.Vector3( -2, -2, 0 ),
      new THREE.Vector3( -6, -1, 0 ),
      new THREE.Vector3( -4,  0, 0 ),

      new THREE.Vector3( -7,  1, 0 ),
      new THREE.Vector3( -1,  2, 0 ),
      new THREE.Vector3( -6,  3, 0 ),
      new THREE.Vector3( -3,  3, 0 ),

      new THREE.Vector3( -7,  6, 0 ),
      new THREE.Vector3( -3,  6, 0 ),
      new THREE.Vector3( -5,  7, 0 ),
      new THREE.Vector3( -1,  7, 0 ),

      new THREE.Vector3(  5, -7, 0 ),
      new THREE.Vector3(  1, -6, 0 ),
      new THREE.Vector3(  6, -5, 0 ),
      new THREE.Vector3(  4, -4, 0 ),

      new THREE.Vector3(  2, -3, 0 ),
      new THREE.Vector3(  7, -2, 0 ),
      new THREE.Vector3(  1, -1, 0 ),
      new THREE.Vector3(  4, -1, 0 ),

      new THREE.Vector3(  2,  1, 0 ),
      new THREE.Vector3(  6,  2, 0 ),
      new THREE.Vector3(  0,  4, 0 ),
      new THREE.Vector3(  4,  4, 0 ),

      new THREE.Vector3(  2,  5, 0 ),
      new THREE.Vector3(  7,  5, 0 ),
      new THREE.Vector3(  5,  6, 0 ),
      new THREE.Vector3(  3,  7, 0 ),
    ];
    var xfrm = new THREE.Matrix4().makeScale( 1 / 16.0, 1/ 16.0, 0 );
    var vectors2 = [];
    for( var i = 0; i < vectors.length; i ++ ) {
      vectors2.push( vectors[i].clone().applyMatrix4( xfrm ) );
    }
    return vectors2;
  }

};