(function (factory) {
    if (typeof define === "function" && define.amd) {
        define(['three-full'], factory);
    } else if (typeof exports === 'object' && typeof module !== 'undefined') {
        factory(require("three-full"), exports);
    } else {

        if (typeof THREE == 'undefined')
            throw new Error('THREE is not defined', 'ThreeCSG.js');

        ThreeBSP = factory(THREE);
    }
}(function (THREE, ThreeBSP) {

    "use strict";

    if (!ThreeBSP) ThreeBSP = {};

    var EPSILON = 1e-5,
        COPLANAR = 0,
        FRONT = 1,
        BACK = 2,
        SPANNING = 3;

    ThreeBSP.Geometry = function (geometry, transfer_matrix, nodeid, flippedMesh) {
        // Convert THREE.Geometry to ThreeBSP

        if (geometry instanceof THREE.Geometry) {
            this.matrix = null; // new THREE.Matrix4; not create matrix when do not needed
        } else if (geometry instanceof THREE.Mesh) {
            // #todo: add hierarchy support
            geometry.updateMatrix();
            transfer_matrix = this.matrix = geometry.matrix.clone();
            geometry = geometry.geometry;
        } else if (geometry instanceof ThreeBSP.Node) {
            this.tree = geometry;
            this.matrix = null; // new THREE.Matrix4;
            return this;
        } else if (geometry instanceof THREE.BufferGeometry) {
            var pos_buf = geometry.getAttribute('position').array,
                norm_buf = geometry.getAttribute('normal').array,
                polygons = [], polygon, vert1, vert2, vert3;

            for (var i = 0; i < pos_buf.length; i += 9) {
                polygon = new ThreeBSP.Polygon;

                vert1 = new ThreeBSP.Vertex(pos_buf[i], pos_buf[i + 1], pos_buf[i + 2], norm_buf[i], norm_buf[i + 1], norm_buf[i + 2]);
                if (transfer_matrix) vert1.applyMatrix4(transfer_matrix);

                vert2 = new ThreeBSP.Vertex(pos_buf[i + 3], pos_buf[i + 4], pos_buf[i + 5], norm_buf[i + 3], norm_buf[i + 4], norm_buf[i + 5]);
                if (transfer_matrix) vert2.applyMatrix4(transfer_matrix);

                vert3 = new ThreeBSP.Vertex(pos_buf[i + 6], pos_buf[i + 7], pos_buf[i + 8], norm_buf[i + 6], norm_buf[i + 7], norm_buf[i + 8]);
                if (transfer_matrix) vert3.applyMatrix4(transfer_matrix);

                if (flippedMesh) polygon.vertices.push(vert1, vert3, vert2);
                else polygon.vertices.push(vert1, vert2, vert3);

                polygon.calculateProperties();
                polygons.push(polygon);
            }

            this.tree = new ThreeBSP.Node(polygons, nodeid);
            if (nodeid !== undefined) this.maxid = this.tree.maxnodeid;
            return this;

        } else if (geometry.polygons && (geometry.polygons[0] instanceof ThreeBSP.Polygon)) {
            var polygons = geometry.polygons;

            for (var i = 0; i < polygons.length; ++i) {
                var polygon = polygons[i];
                if (transfer_matrix) {
                    for (var n = 0; n < polygon.vertices.length; ++n)
                        polygon.vertices[n].applyMatrix4(transfer_matrix);
                }

                polygon.calculateProperties();
            }

            this.tree = new ThreeBSP.Node(polygons, nodeid);
            if (nodeid !== undefined) this.maxid = this.tree.maxnodeid;
            return this;

        } else {
            throw 'ThreeBSP: Given geometry is unsupported';
        }

        var polygons = [],
            nfaces = geometry.faces.length,
            face, polygon, vertex;

        for (var i = 0; i < nfaces; ++i) {
            face = geometry.faces[i];
            // faceVertexUvs = geometry.faceVertexUvs[0][i];
            polygon = new ThreeBSP.Polygon;

            if (face instanceof THREE.Face3) {
                vertex = geometry.vertices[face.a];
                // uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[0].x, faceVertexUvs[0].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[0].x, face.vertexNormals[0].y, face.vertexNormals[0].z /*face.normal , uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);

                vertex = geometry.vertices[face.b];
                //uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[1].x, faceVertexUvs[1].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[1].x, face.vertexNormals[1].y, face.vertexNormals[1].z/*face.normal , uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);

                vertex = geometry.vertices[face.c];
                // uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[2].x, faceVertexUvs[2].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[2].x, face.vertexNormals[2].y, face.vertexNormals[2].z /*face.normal, uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);
            } else if (typeof THREE.Face4) {
                vertex = geometry.vertices[face.a];
                // uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[0].x, faceVertexUvs[0].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[0].x, face.vertexNormals[0].y, face.vertexNormals[0].z /*, uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);

                vertex = geometry.vertices[face.b];
                // uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[1].x, faceVertexUvs[1].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[1].x, face.vertexNormals[1].y, face.vertexNormals[1].z /*, uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);

                vertex = geometry.vertices[face.c];
                // uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[2].x, faceVertexUvs[2].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[2].x, face.vertexNormals[2].y, face.vertexNormals[2].z /*, uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);

                vertex = geometry.vertices[face.d];
                // uvs = faceVertexUvs ? new THREE.Vector2( faceVertexUvs[3].x, faceVertexUvs[3].y ) : null;
                vertex = new ThreeBSP.Vertex(vertex.x, vertex.y, vertex.z, face.vertexNormals[3].x, face.vertexNormals[3].y, face.vertexNormals[3].z /*, uvs */);
                if (transfer_matrix) vertex.applyMatrix4(transfer_matrix);
                polygon.vertices.push(vertex);
            } else {
                throw 'Invalid face type at index ' + i;
            }

            polygon.calculateProperties();
            polygons.push(polygon);
        }

        this.tree = new ThreeBSP.Node(polygons, nodeid);
        if (nodeid !== undefined) this.maxid = this.tree.maxnodeid;
    };

    ThreeBSP.Geometry.prototype.subtract = function (other_tree) {
        var a = this.tree.clone(),
            b = other_tree.tree.clone();

        a.invert();
        a.clipTo(b);
        b.clipTo(a);
        b.invert();
        b.clipTo(a);
        b.invert();
        a.build(b.allPolygons());
        a.invert();
        a = new ThreeBSP.Geometry(a);
        a.matrix = this.matrix;
        return a;
    };

    ThreeBSP.Geometry.prototype.union = function (other_tree) {
        var a = this.tree.clone(),
            b = other_tree.tree.clone();

        a.clipTo(b);
        b.clipTo(a);
        b.invert();
        b.clipTo(a);
        b.invert();
        a.build(b.allPolygons());
        a = new ThreeBSP.Geometry(a);
        a.matrix = this.matrix;
        return a;
    };

    ThreeBSP.Geometry.prototype.intersect = function (other_tree) {
        var a = this.tree.clone(),
            b = other_tree.tree.clone();

        a.invert();
        b.clipTo(a);
        b.invert();
        a.clipTo(b);
        b.clipTo(a);
        a.build(b.allPolygons());
        a.invert();
        a = new ThreeBSP.Geometry(a);
        a.matrix = this.matrix;
        return a;
    };

    ThreeBSP.Geometry.prototype.tryToCompress = function (polygons) {

        if (this.maxid === undefined) return;

        var arr = [], parts, foundpair,
            nreduce = 0, n, len = polygons.length,
            p, p1, p2, i1, i2;

        // sort out polygons
        for (n = 0; n < len; ++n) {
            p = polygons[n];
            if (p.id === undefined) continue;
            if (arr[p.id] === undefined) arr[p.id] = [];

            arr[p.id].push(p);
        }

        for (n = 0; n < arr.length; ++n) {
            parts = arr[n];
            if (parts === undefined) continue;

            len = parts.length;

            foundpair = (len > 1);

            while (foundpair) {
                foundpair = false;

                for (i1 = 0; i1 < len - 1; ++i1) {
                    p1 = parts[i1];
                    if (!p1 || !p1.parent) continue;
                    for (i2 = i1 + 1; i2 < len; ++i2) {
                        p2 = parts[i2];
                        if (p2 && (p1.parent === p2.parent) && (p1.nsign === p2.nsign)) {

                            if (p1.nsign !== p1.parent.nsign) p1.parent.flip();

                            nreduce++;
                            parts[i1] = p1.parent;
                            parts[i2] = null;
                            if (p1.parent.vertices.length < 3) console.log('something wrong with parent');
                            foundpair = true;
                            break;
                        }
                    }
                }
            }
        }

        if (nreduce > 0) {
            polygons.splice(0, polygons.length);

            for (n = 0; n < arr.length; ++n) {
                parts = arr[n];
                if (parts !== undefined)
                    for (i1 = 0, len = parts.length; i1 < len; ++i1)
                        if (parts[i1]) polygons.push(parts[i1]);
            }

        }
    };

    ThreeBSP.Geometry.prototype.direct_subtract = function (other_tree) {
        var a = this.tree,
            b = other_tree.tree;
        a.invert();
        a.clipTo(b);
        b.clipTo(a);
        b.invert();
        b.clipTo(a);
        b.invert();
        a.build(b.collectPolygons([]));
        a.invert();
        return this;
    };

    ThreeBSP.Geometry.prototype.direct_union = function (other_tree) {
        var a = this.tree,
            b = other_tree.tree;

        a.clipTo(b);
        b.clipTo(a);
        b.invert();
        b.clipTo(a);
        b.invert();
        a.build(b.collectPolygons([]));
        return this;
    };

    ThreeBSP.Geometry.prototype.direct_intersect = function (other_tree) {
        var a = this.tree,
            b = other_tree.tree;

        a.invert();
        b.clipTo(a);
        b.invert();
        a.clipTo(b);
        b.clipTo(a);
        a.build(b.collectPolygons([]));
        a.invert();
        return this;
    };

    ThreeBSP.CreateNormal = function (axis_name, pos, size) {
        // create geometry to make cut on specified axis

        var vert1, vert2, vert3;

        if (!size || (size < 10000)) size = 10000;

        switch (axis_name) {
            case "x":
                vert1 = new ThreeBSP.Vertex(pos, -3 * size, size, 1, 0, 0),
                    vert3 = new ThreeBSP.Vertex(pos, size, size, 1, 0, 0),
                    vert2 = new ThreeBSP.Vertex(pos, size, -3 * size, 1, 0, 0);
                break;
            case "y":
                vert1 = new ThreeBSP.Vertex(-3 * size, pos, size, 0, 1, 0),
                    vert2 = new ThreeBSP.Vertex(size, pos, size, 0, 1, 0),
                    vert3 = new ThreeBSP.Vertex(size, pos, -3 * size, 0, 1, 0);
                break;
            case "z":
                vert1 = new ThreeBSP.Vertex(-3 * size, size, pos, 0, 0, 1),
                    vert3 = new ThreeBSP.Vertex(size, size, pos, 0, 0, 1),
                    vert2 = new ThreeBSP.Vertex(size, -3 * size, pos, 0, 0, 1);
                break;
        }

        var polygon = new ThreeBSP.Polygon([vert1, vert2, vert3]);
        polygon.calculateProperties();

        var node = new ThreeBSP.Node([polygon]);

        return new ThreeBSP.Geometry(node);
    };


    ThreeBSP.Geometry.prototype.cut_from_plane = function (other_tree) {
        // just cut peaces from second geometry, which just simple plane

        var a = this.tree,
            b = other_tree.tree;

        a.invert();
        b.clipTo(a);

        return this;
    };


    ThreeBSP.Geometry.prototype.toGeometry = function () {
        var i, j,
            matrix = this.matrix ? new THREE.Matrix4().getInverse(this.matrix) : null,
            geometry = new THREE.Geometry(),
            polygons = this.tree.collectPolygons([]),
            polygon_count = polygons.length,
            polygon, polygon_vertice_count,
            vertice_dict = {},
            vertex_idx_a, vertex_idx_b, vertex_idx_c,
            vertex, face;

        for (i = 0; i < polygon_count; ++i) {
            polygon = polygons[i];
            polygon_vertice_count = polygon.vertices.length;

            for (j = 2; j < polygon_vertice_count; ++j) {
                // verticeUvs = [];

                vertex = polygon.vertices[0];
                // verticeUvs.push( new THREE.Vector2( vertex.uv.x, vertex.uv.y ) );
                vertex = new THREE.Vector3(vertex.x, vertex.y, vertex.z);
                if (matrix) vertex.applyMatrix4(matrix);

                if (typeof vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z] !== 'undefined') {
                    vertex_idx_a = vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z];
                } else {
                    geometry.vertices.push(vertex);
                    vertex_idx_a = vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z] = geometry.vertices.length - 1;
                }

                vertex = polygon.vertices[j - 1];
                // verticeUvs.push( new THREE.Vector2( vertex.uv.x, vertex.uv.y ) );
                vertex = new THREE.Vector3(vertex.x, vertex.y, vertex.z);
                if (matrix) vertex.applyMatrix4(matrix);
                if (typeof vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z] !== 'undefined') {
                    vertex_idx_b = vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z];
                } else {
                    geometry.vertices.push(vertex);
                    vertex_idx_b = vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z] = geometry.vertices.length - 1;
                }

                vertex = polygon.vertices[j];
                // verticeUvs.push( new THREE.Vector2( vertex.uv.x, vertex.uv.y ) );
                vertex = new THREE.Vector3(vertex.x, vertex.y, vertex.z);
                if (matrix) vertex.applyMatrix4(matrix);
                if (typeof vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z] !== 'undefined') {
                    vertex_idx_c = vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z];
                } else {
                    geometry.vertices.push(vertex);
                    vertex_idx_c = vertice_dict[vertex.x + ',' + vertex.y + ',' + vertex.z] = geometry.vertices.length - 1;
                }

                face = new THREE.Face3(
                    vertex_idx_a,
                    vertex_idx_b,
                    vertex_idx_c,
                    new THREE.Vector3(polygon.normal.x, polygon.normal.y, polygon.normal.z)
                );

                geometry.faces.push(face);
                // geometry.faceVertexUvs[0].push( verticeUvs );
            }

        }
        return geometry;
    };

    ThreeBSP.Geometry.prototype.scale = function (x, y, z) {
        // try to scale as THREE.BufferGeometry
        var polygons = this.tree.collectPolygons([]);

        for (var i = 0; i < polygons.length; ++i) {
            var polygon = polygons[i];
            for (var k = 0; k < polygon.vertices.length; ++k) {
                var v = polygon.vertices[k];
                v.x *= x;
                v.y *= y;
                v.z *= z;
            }
            delete polygon.normal;
            polygon.calculateProperties();
        }
    };

    ThreeBSP.Geometry.prototype.toPolygons = function () {
        var polygons = this.tree.collectPolygons([]);

        this.tryToCompress(polygons);

        for (var i = 0; i < polygons.length; ++i) {
            delete polygons[i].id;
            delete polygons[i].parent;
        }

        return polygons;
    };

    ThreeBSP.Geometry.prototype.toBufferGeometry = function () {
        return ThreeBSP.CreateBufferGeometry(this.toPolygons());
    };

    ThreeBSP.CreateBufferGeometry = function (polygons) {
        var i, j, polygon_count = polygons.length, buf_size = 0;

        for (i = 0; i < polygon_count; ++i)
            buf_size += (polygons[i].vertices.length - 2) * 9;

        var positions_buf = new Float32Array(buf_size),
            normals_buf = new Float32Array(buf_size),
            iii = 0, polygon;

        function CopyVertex(vertex) {

            positions_buf[iii] = vertex.x;
            positions_buf[iii + 1] = vertex.y;
            positions_buf[iii + 2] = vertex.z;

            normals_buf[iii] = polygon.nsign * vertex.nx;
            normals_buf[iii + 1] = polygon.nsign * vertex.ny;
            normals_buf[iii + 2] = polygon.nsign * vertex.nz;
            iii += 3;
        }

        for (i = 0; i < polygon_count; ++i) {
            polygon = polygons[i];
            for (j = 2; j < polygon.vertices.length; ++j) {
                CopyVertex(polygon.vertices[0]);
                CopyVertex(polygon.vertices[j - 1]);
                CopyVertex(polygon.vertices[j]);
            }
        }

        var geometry = new THREE.BufferGeometry();
        geometry.addAttribute('position', new THREE.BufferAttribute(positions_buf, 3));
        geometry.addAttribute('normal', new THREE.BufferAttribute(normals_buf, 3));

        // geometry.computeVertexNormals();
        return geometry;
    };

    ThreeBSP.Geometry.prototype.toMesh = function (material) {
        var geometry = this.toGeometry(),
            mesh = new THREE.Mesh(geometry, material);

        if (this.matrix) {
            mesh.position.setFromMatrixPosition(this.matrix);
            mesh.rotation.setFromRotationMatrix(this.matrix);
        }

        return mesh;
    };

    ThreeBSP.Polygon = function (vertices, normal, w) {
        if (!(vertices instanceof Array)) {
            vertices = [];
        }

        this.vertices = vertices;
        this.nsign = 1;
        if (vertices.length > 0) {
            this.calculateProperties();
        } else {
            this.normal = this.w = undefined;
        }
    };

    ThreeBSP.Polygon.prototype.copyProperties = function (parent, more) {
        this.normal = parent.normal; // .clone();
        this.w = parent.w;
        this.nsign = parent.nsign;
        if (more && (parent.id !== undefined)) {
            this.id = parent.id;
            this.parent = parent;
        }
        return this;
    };

    ThreeBSP.Polygon.prototype.calculateProperties = function () {
        if (this.normal) return;

        var a = this.vertices[0],
            b = this.vertices[1],
            c = this.vertices[2];

        this.nsign = 1;

        this.normal = b.clone().subtract(a).cross(
            c.clone().subtract(a)
        ).normalize();

        this.w = this.normal.clone().dot(a);
        return this;
    };

    ThreeBSP.Polygon.prototype.clone = function () {
        var vertice_count = this.vertices.length,
            polygon = new ThreeBSP.Polygon;

        for (var i = 0; i < vertice_count; ++i)
            polygon.vertices.push(this.vertices[i].clone());

        return polygon.copyProperties(this);
    };

    ThreeBSP.Polygon.prototype.flip = function () {

        /// normal is not changed, only sign variable
        //this.normal.multiplyScalar( -1 );
        //this.w *= -1;

        this.nsign *= -1;

        this.vertices.reverse();

        return this;
    };

    ThreeBSP.Polygon.prototype.classifyVertex = function (vertex) {
        var side_value = this.nsign * (this.normal.dot(vertex) - this.w);

        if (side_value < -EPSILON) return BACK;
        if (side_value > EPSILON) return FRONT;
        return COPLANAR;
    };

    ThreeBSP.Polygon.prototype.classifySide = function (polygon) {
        var i, classification,
            num_positive = 0, num_negative = 0,
            vertice_count = polygon.vertices.length;

        for (i = 0; i < vertice_count; ++i) {
            classification = this.classifyVertex(polygon.vertices[i]);
            if (classification === FRONT) {
                ++num_positive;
            } else if (classification === BACK) {
                ++num_negative;
            }
        }

        if (num_positive > 0 && num_negative === 0) return FRONT;
        if (num_positive === 0 && num_negative > 0) return BACK;
        if (num_positive === 0 && num_negative === 0) return COPLANAR;
        return SPANNING;
    };

    ThreeBSP.Polygon.prototype.splitPolygon = function (polygon, coplanar_front, coplanar_back, front, back) {
        var classification = this.classifySide(polygon);

        if (classification === COPLANAR) {

            ((this.nsign * polygon.nsign * this.normal.dot(polygon.normal) > 0) ? coplanar_front : coplanar_back).push(polygon);

        } else if (classification === FRONT) {

            front.push(polygon);

        } else if (classification === BACK) {

            back.push(polygon);

        } else {

            var vertice_count = polygon.vertices.length,
                nnx = this.normal.x,
                nny = this.normal.y,
                nnz = this.normal.z,
                i, j, ti, tj, vi, vj,
                t, v,
                f = [], b = [];

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

                j = (i + 1) % vertice_count;
                vi = polygon.vertices[i];
                vj = polygon.vertices[j];
                ti = this.classifyVertex(vi);
                tj = this.classifyVertex(vj);

                if (ti != BACK) f.push(vi);
                if (ti != FRONT) b.push(vi);
                if ((ti | tj) === SPANNING) {
                    // t = ( this.w - this.normal.dot( vi ) ) / this.normal.dot( vj.clone().subtract( vi ) );
                    //v = vi.clone().lerp( vj, t );

                    t = (this.w - (nnx * vi.x + nny * vi.y + nnz * vi.z)) / (nnx * (vj.x - vi.x) + nny * (vj.y - vi.y) + nnz * (vj.z - vi.z));

                    v = vi.interpolate(vj, t);
                    f.push(v);
                    b.push(v);
                }
            }

            //if ( f.length >= 3 ) front.push( new ThreeBSP.Polygon( f ).calculateProperties() );
            //if ( b.length >= 3 ) back.push( new ThreeBSP.Polygon( b ).calculateProperties() );
            if (f.length >= 3) front.push(new ThreeBSP.Polygon(f).copyProperties(polygon, true));
            if (b.length >= 3) back.push(new ThreeBSP.Polygon(b).copyProperties(polygon, true));
        }
    };

    ThreeBSP.Vertex = function (x, y, z, nx, ny, nz) {
        this.x = x;
        this.y = y;
        this.z = z;
        this.nx = nx;
        this.ny = ny;
        this.nz = nz;
    };

    ThreeBSP.Vertex.prototype.setnormal = function (nx, ny, nz) {
        this.nx = nx;
        this.ny = ny;
        this.nz = nz;
    };

    ThreeBSP.Vertex.prototype.clone = function () {
        return new ThreeBSP.Vertex(this.x, this.y, this.z, this.nx, this.ny, this.nz);
    };

    ThreeBSP.Vertex.prototype.add = function (vertex) {
        this.x += vertex.x;
        this.y += vertex.y;
        this.z += vertex.z;
        return this;
    };

    ThreeBSP.Vertex.prototype.subtract = function (vertex) {
        this.x -= vertex.x;
        this.y -= vertex.y;
        this.z -= vertex.z;
        return this;
    };

    ThreeBSP.Vertex.prototype.multiplyScalar = function (scalar) {
        this.x *= scalar;
        this.y *= scalar;
        this.z *= scalar;
        return this;
    };

    ThreeBSP.Vertex.prototype.cross = function (vertex) {
        var x = this.x,
            y = this.y,
            z = this.z;

        this.x = y * vertex.z - z * vertex.y;
        this.y = z * vertex.x - x * vertex.z;
        this.z = x * vertex.y - y * vertex.x;

        return this;
    };

    ThreeBSP.Vertex.prototype.normalize = function () {
        var length = Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z);

        this.x /= length;
        this.y /= length;
        this.z /= length;

        return this;
    };

    ThreeBSP.Vertex.prototype.dot = function (vertex) {
        return this.x * vertex.x + this.y * vertex.y + this.z * vertex.z;
    };

    ThreeBSP.Vertex.prototype.diff = function (vertex) {
        var dx = (this.x - vertex.x),
            dy = (this.y - vertex.y),
            dz = (this.z - vertex.z),
            len2 = this.x * this.x + this.y * this.y + this.z * this.z;

        return (dx * dx + dy * dy + dz * dz) / (len2 > 0 ? len2 : 1e-10);
    };

    /*
       ThreeBSP.Vertex.prototype.lerp = function( a, t ) {
          this.add(
             a.clone().subtract( this ).multiplyScalar( t )
          );

          this.normal.add(
             a.normal.clone().sub( this.normal ).multiplyScalar( t )
          );

          //this.uv.add(
          //   a.uv.clone().sub( this.uv ).multiplyScalar( t )
          //);

          return this;
       };
       ThreeBSP.Vertex.prototype.interpolate = function( other, t ) {
          return this.clone().lerp( other, t );
       };
    */

    ThreeBSP.Vertex.prototype.interpolate = function (a, t) {
        var t1 = 1 - t;
        return new ThreeBSP.Vertex(this.x * t1 + a.x * t, this.y * t1 + a.y * t, this.z * t1 + a.z * t,
            this.nx * t1 + a.nx * t, this.ny * t1 + a.ny * t, this.nz * t1 + a.nz * t);
    };

    ThreeBSP.Vertex.prototype.applyMatrix4 = function (m) {

        // input: THREE.Matrix4 affine matrix

        var x = this.x, y = this.y, z = this.z, e = m.elements;

        this.x = e[0] * x + e[4] * y + e[8] * z + e[12];
        this.y = e[1] * x + e[5] * y + e[9] * z + e[13];
        this.z = e[2] * x + e[6] * y + e[10] * z + e[14];

        x = this.nx;
        y = this.ny;
        z = this.nz;

        this.nx = e[0] * x + e[4] * y + e[8] * z;
        this.ny = e[1] * x + e[5] * y + e[9] * z;
        this.nz = e[2] * x + e[6] * y + e[10] * z;

        return this;
    };

    // ================================================================================================

    ThreeBSP.Node = function (polygons, nodeid) {
        this.polygons = [];
        this.front = this.back = undefined;

        if (!(polygons instanceof Array) || polygons.length === 0) return;

        this.divider = polygons[0].clone();

        var polygon_count = polygons.length,
            front = [], back = [];

        for (var i = 0; i < polygon_count; ++i) {
            if (nodeid !== undefined) {
                polygons[i].id = nodeid++;
                delete polygons[i].parent;
            }

            this.divider.splitPolygon(polygons[i], this.polygons, this.polygons, front, back);
        }

        if (nodeid !== undefined) this.maxnodeid = nodeid;

        if (front.length > 0)
            this.front = new ThreeBSP.Node(front);

        if (back.length > 0)
            this.back = new ThreeBSP.Node(back);
    };

    ThreeBSP.Node.isConvex = function (polygons) {
        var i, j, len = polygons.length;
        for (i = 0; i < len; ++i)
            for (j = 0; j < len; ++j)
                if (i !== j && polygons[i].classifySide(polygons[j]) !== BACK) return false;
        return true;
    };

    ThreeBSP.Node.prototype.build = function (polygons) {
        var polygon_count = polygons.length,
            front = [], back = [];

        if (!this.divider)
            this.divider = polygons[0].clone();

        for (var i = 0; i < polygon_count; ++i)
            this.divider.splitPolygon(polygons[i], this.polygons, this.polygons, front, back);

        if (front.length > 0) {
            if (!this.front) this.front = new ThreeBSP.Node();
            this.front.build(front);
        }

        if (back.length > 0) {
            if (!this.back) this.back = new ThreeBSP.Node();
            this.back.build(back);
        }
    };

    ThreeBSP.Node.prototype.collectPolygons = function (arr) {
        var len = this.polygons.length;
        for (var i = 0; i < len; ++i) arr.push(this.polygons[i]);
        if (this.front) this.front.collectPolygons(arr);
        if (this.back) this.back.collectPolygons(arr);
        return arr;
    };

    ThreeBSP.Node.prototype.allPolygons = function () {
        var polygons = this.polygons.slice();
        if (this.front) polygons = polygons.concat(this.front.allPolygons());
        if (this.back) polygons = polygons.concat(this.back.allPolygons());
        return polygons;
    };

    ThreeBSP.Node.prototype.numPolygons = function () {
        var res = this.polygons.length;
        if (this.front) res += this.front.numPolygons();
        if (this.back) res += this.back.numPolygons();
        return res;
    };

    ThreeBSP.Node.prototype.clone = function () {
        var node = new ThreeBSP.Node();

        node.divider = this.divider.clone();
        node.polygons = this.polygons.map(function (polygon) {
            return polygon.clone();
        });
        node.front = this.front && this.front.clone();
        node.back = this.back && this.back.clone();

        return node;
    };

    ThreeBSP.Node.prototype.invert = function () {
        var polygon_count = this.polygons.length;

        for (var i = 0; i < polygon_count; ++i)
            this.polygons[i].flip();

        this.divider.flip();
        if (this.front) this.front.invert();
        if (this.back) this.back.invert();

        var temp = this.front;
        this.front = this.back;
        this.back = temp;

        return this;
    };

    ThreeBSP.Node.prototype.clipPolygons = function (polygons) {

        if (!this.divider) return polygons.slice();

        var polygon_count = polygons.length, front = [], back = [];

        for (var i = 0; i < polygon_count; ++i)
            this.divider.splitPolygon(polygons[i], front, back, front, back);

        if (this.front) front = this.front.clipPolygons(front);
        if (this.back) back = this.back.clipPolygons(back);
        else back = [];

        return front.concat(back);
    };

    ThreeBSP.Node.prototype.clipTo = function (node) {
        this.polygons = node.clipPolygons(this.polygons);
        if (this.front) this.front.clipTo(node);
        if (this.back) this.back.clipTo(node);
    };

    return ThreeBSP;

}));