three-dimensional-covert/service/util/math.js

import * as THREE from 'three'

var math = {
    getBaseLog(x, y) {
        //返回以 x 为底 y 的对数（即 logx y） .  Math.log 返回一个数的自然对数
        return Math.log(y) / Math.log(x)
    },
    convertVisionVector: function (e) {
        return new THREE.Vector3(e.x, e.z, -e.y)
    },
    invertVisionVector: function (e) {
        //反转给算法部
        return new THREE.Vector3(e.x, -e.z, e.y)
    },
    convertVisionQuaternion: function (e) {
        return new THREE.Quaternion(e.x, e.z, -e.y, e.w).multiply(new THREE.Quaternion().setFromAxisAngle(new THREE.Vector3(0, 1, 0), THREE.MathUtils.degToRad(90)))
    },
    invertVisionQuaternion: function (e) {
        //反转给算法部
        var a = e.clone().multiply(new THREE.Quaternion().setFromAxisAngle(new THREE.Vector3(0, 1, 0), THREE.MathUtils.degToRad(-90)))
        return new THREE.Quaternion(a.x, -a.z, a.y, a.w)
    },
    convertWorkshopVector: function (e) {
        return new THREE.Vector3(-e.x, e.y, e.z)
    },
    convertWorkshopQuaternion: function (e) {
        return new THREE.Quaternion(-e.x, e.y, e.z, -e.w).multiply(new THREE.Quaternion(Math.sqrt(2) / 2, Math.sqrt(2) / 2, 0, 0))
    },
    convertWorkshopPanoramaQuaternion: function (e) {
        return new THREE.Quaternion(e.x, -e.y, -e.z, e.w).normalize().multiply(new THREE.Quaternion().setFromAxisAngle(new THREE.Vector3(0, 1, 0), THREE.MathUtils.degToRad(270)))
    },
    convertWorkshopOrthoZoom: function (e, dom) {
        //xzw
        return e === -1 ? -1 : e * (dom.clientHeight / dom.clientHeight)
    },

    getVec2Angle: function (dir1, dir2) {
        return Math.acos(THREE.MathUtils.clamp(this.getVec2Cos(dir1, dir2), -1, 1))
    },
    getVec2Cos: function (dir1, dir2) {
        return dir1.dot(dir2) / dir1.length() / dir2.length()
    },

    closeTo: function (a, b, num) {
        if (num != void 0) return Math.abs(a - b) < num
        return Math.abs(a - b) < 1e-6
    },
    toPrecision: function (e, t) {
        //xzw change 保留小数
        var f = function (e, t) {
            var i = Math.pow(10, t)
            return Math.round(e * i) / i
        }
        if (e instanceof Array) {
            for (var s = 0; s < e.length; s++) {
                e[s] = f(e[s], t)
            }
            return e
        } else if (e instanceof Object) {
            for (var s in e) {
                e[s] = f(e[s], t)
            }
            return e
        } else return f(e, t)
    },
    isEmptyQuaternion: function (e) {
        return 0 === Math.abs(e.x) && 0 === Math.abs(e.y) && 0 === Math.abs(e.z) && 0 === Math.abs(e.w)
    },
    projectPositionToCanvas: function (e, t, i, domE) {
        ;(i = i || new THREE.Vector3()), i.copy(e)
        var r = 0.5 * domE.clientWidth,
            o = 0.5 * domE.clientHeight
        return i.project(t), (i.x = i.x * r + r), (i.y = -(i.y * o) + o), i
    },
    convertScreenPositionToNDC: function (e, t, i, domE) {
        /* return i = i || new THREE.Vector2,
        i.x = e / window.innerWidth * 2 - 1,
        i.y = 2 * -(t / window.innerHeight) + 1,
        i
		 */

        return (i = i || new n.Vector2()), (i.x = (e / domE.clientWidth) * 2 - 1), (i.y = 2 * -(t / domE.clientHeight) + 1), i
    },

    handelPadding: (function () {
        //去除player左边和上面的宽高,因为pc的player左上有其他element  许钟文

        var pads = new Map() //记录下来避免反复计算

        return function (x, y, domE) {
            let pad

            let padInfo = pads.get(domE)
            if (padInfo) {
                if (domE.clientWidth == padInfo.width && domE.clientHeight == padInfo.height) {
                    pad = padInfo.pad
                }
            }
            if (!pad) {
                pad = {
                    x: this.getOffset('left', domE),
                    y: this.getOffset('top', domE),
                }

                pads.set(domE, {
                    width: domE.clientWidth,
                    height: domE.clientHeight,
                    pad,
                })
            }

            return {
                x: x - pad.x,
                y: y - pad.y,
            }
        }
    })(),

    getOffset: function (type, element, parent) {
        //获取元素的边距 许钟文
        var offset = type == 'left' ? element.offsetLeft : element.offsetTop
        if (!parent) parent = document.body
        while ((element = element.offsetParent)) {
            if (element == parent) break
            offset += type == 'left' ? element.offsetLeft : element.offsetTop
        }
        return offset
    },

    constrainedTurn: function (e) {
        var t = e % (2 * Math.PI)
        return (t = t > Math.PI ? (t -= 2 * Math.PI) : t < -Math.PI ? (t += 2 * Math.PI) : t)
    },
    getFOVDotThreshold: function (e) {
        return Math.cos(THREE.MathUtils.degToRad(e / 2))
    },
    transform2DForwardVectorByCubeFace: function (e, t, i, n) {
        switch (e) {
            case GLCubeFaces.GL_TEXTURE_CUBE_MAP_POSITIVE_X:
                i.set(1, t.y, t.x)
                break
            case GLCubeFaces.GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
                i.set(-1, t.y, -t.x)
                break
            case GLCubeFaces.GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
                i.set(-t.x, 1, -t.y)
                break
            case GLCubeFaces.GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
                i.set(-t.x, -1, t.y)
                break
            case GLCubeFaces.GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
                i.set(-t.x, t.y, 1)
                break
            case GLCubeFaces.GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
                i.set(t.x, t.y, -1)
        }
        n && i.normalize()
    },

    getFootPoint: function (oldPos, p1, p2, restricInline) {
        //找oldPos在线段p1, p2上的垂足
        /* if(isWorld){//输出全局坐标 需要考虑meshGroup.position
			p1 = p1.clone();
			p2 = p2.clone();
			p1.y += mainDesign.meshGroup.position.y;
			p2.y += mainDesign.meshGroup.position.y;
		} */
        var op1 = oldPos.clone().sub(p1)
        var p1p2 = p1.clone().sub(p2)
        var p1p2Len = p1p2.length()
        var leftLen = op1.dot(p1p2) / p1p2Len
        var pos = p1.clone().add(p1p2.multiplyScalar(leftLen / p1p2Len))

        if (restricInline && pos.clone().sub(p1).dot(pos.clone().sub(p2)) > 0) {
            //foot不在线段上
            if (pos.distanceTo(p1) < pos.distanceTo(p2)) pos = p1.clone()
            else pos = p2.clone()
        }

        return pos
    },

    /**
     * 计算多边形的重心
     * @param {*} points
     */
    getCenterOfGravityPoint: function (mPoints) {
        var area = 0.0 //多边形面积
        var Gx = 0.0,
            Gy = 0.0 // 重心的x、y

        for (var i = 1; i <= mPoints.length; i++) {
            var ix = mPoints[i % mPoints.length].x
            var iy = mPoints[i % mPoints.length].y
            var nx = mPoints[i - 1].x
            var ny = mPoints[i - 1].y
            var temp = (ix * ny - iy * nx) / 2.0
            area += temp
            Gx += (temp * (ix + nx)) / 3.0
            Gy += (temp * (iy + ny)) / 3.0
        }
        Gx = Gx / area
        Gy = Gy / area
        return { x: Gx, y: Gy }
    },

    getBound: function (ring) {
        var bound = new THREE.Box2()
        for (var j = 0, len = ring.length; j < len; j++) {
            bound.expandByPoint(ring[j])
        }
        return bound
    },

    isPointInArea: function (ring, point, ifAtLine) {
        //判断点是否在某个环内
        var bound = this.getBound(ring)
        if (point.x < bound.min.x || point.x > bound.max.x || point.y < bound.min.y || point.y > bound.max.y) return false

        var inside = false
        var x = point.x,
            y = point.y

        for (var i = 0, j = ring.length - 1; i < ring.length; j = i++) {
            var xi = ring[i].x,
                yi = ring[i].y
            var xj = ring[j].x,
                yj = ring[j].y

            if (
                (xi - x) * (yj - y) == (xi - x) * (yi - y) &&
                x >= Math.min(xi, xj) &&
                x <= Math.max(xi, xj) && //xzw add
                y >= Math.min(yi, yj) &&
                y <= Math.max(yi, yj)
            ) {
                return !!ifAtLine //在线段上，则判断为…… （默认在外）
            }

            if (yi > y != yj > y && x < ((xj - xi) * (y - yi)) / (yj - yi) + xi) {
                inside = !inside
            }
        }

        return inside
    },

    getArea: function (ring) {
        //求面积  顺时针为正  来自three shape
        for (var t = ring.length, i = 0, n = t - 1, r = 0; r < t; n = r++) i += ring[n].x * ring[r].y - ring[r].x * ring[n].y
        return -0.5 * i
    },
    isInBetween: function (a, b, c, precision) {
        // 如果b几乎等于a或c，返回false.为了避免浮点运行时两值几乎相等，但存在相差0.00000...0001的这种情况出现使用下面方式进行避免

        /* if (Math.abs(a - b) < 0.000001 || Math.abs(b - c) < 0.000001) {
            return false;
        } 
 
        return (a <= b && b <= c) || (c <= b && b <= a);*/

        //更改：如果b和a或c中一个接近 就算在a和c之间
        return (a <= b && b <= c) || (c <= b && b <= a) || this.closeTo(a, b, precision) || this.closeTo(b, c, precision)
    },

    ifPointAtLineBound: function (point, linePoints, precision) {
        //待验证  横线和竖线比较特殊
        return math.isInBetween(linePoints[0].x, point.x, linePoints[1].x, precision) && math.isInBetween(linePoints[0].y, point.y, linePoints[1].y, precision)
    },

    isLineIntersect: function (line1, line2, notSegment) {
        //线段和线段是否有交点.  notSegment代表是直线而不是线段
        var a1 = line1[1].y - line1[0].y
        var b1 = line1[0].x - line1[1].x
        var c1 = a1 * line1[0].x + b1 * line1[0].y
        //转换成一般式: Ax+By = C
        var a2 = line2[1].y - line2[0].y
        var b2 = line2[0].x - line2[1].x
        var c2 = a2 * line2[0].x + b2 * line2[0].y
        // 计算交点
        var d = a1 * b2 - a2 * b1

        // 当d==0时，两线平行
        if (d == 0) {
            return false
        } else {
            var x = (b2 * c1 - b1 * c2) / d
            var y = (a1 * c2 - a2 * c1) / d

            // 检测交点是否在两条线段上
            /* if (notSegment || (isInBetween(line1[0].x, x, line1[1].x) || isInBetween(line1[0].y, y, line1[1].y)) &&
			(isInBetween(line2[0].x, x, line2[1].x) || isInBetween(line2[0].y, y, line2[1].y))) {
			return {x,y};
		  } */
            if (notSegment || (math.ifPointAtLineBound({ x, y }, line1) && math.ifPointAtLineBound({ x, y }, line2))) {
                return { x, y }
            }
        }
    },

    getNormal: function (line2d) {
        //获取二维法向量 方向向内
        var x, y //要求的向量
        //line2d的向量
        var x1 = line2d.points[1].x - line2d.points[0].x
        var y1 = line2d.points[1].y - line2d.points[0].y
        //假设法向量的x或y固定为1或-1
        if (y1 != 0) {
            x = 1
            y = -(x1 * x) / y1
        } else if (x1 != 0) {
            //y如果为0，正常情况x不会是0
            y = 1
            x = -(y1 * y) / x1
        } else {
            console.log('两个点一样')
            return null
        }

        //判断方向里或者外：
        var vNormal = new THREE.Vector3(x, 0, y)
        var vLine = new THREE.Vector3(x1, 0, y1)
        var vDir = vNormal.cross(vLine)
        if (vDir.y > 0) {
            x *= -1
            y *= -1
        }
        return new THREE.Vector2(x, y).normalize()
    },

    getQuaBetween2Vector: function (oriVec, newVec, upVec) {
        //获取从oriVec旋转到newVec可以应用的quaternion
        var angle = oriVec.angleTo(newVec)
        var axis = oriVec.clone().cross(newVec).normalize() //两个up之间
        if (axis.length() == 0) {
            //当夹角为180 或 0 度时，得到的axis为（0,0,0），故使用备用的指定upVec
            return new THREE.Quaternion().setFromAxisAngle(upVec, angle)
        }
        return new THREE.Quaternion().setFromAxisAngle(axis, angle)
    },

    getScaleForConstantSize: (function () {
        //获得规定二维大小的mesh的scale值。可以避免因camera的projection造成的mesh视觉大小改变。  来源：tag.updateDisc
        var w
        var i = new THREE.Vector3(),
            o = new THREE.Vector3(),
            l = new THREE.Vector3(),
            c = new THREE.Vector3(),
            h = new THREE.Vector3()
        return function (op = {}) {
            if (op.width2d) w = op.width2d
            //如果恒定二维宽度
            else {
                var currentDis
                if (op.camera.type == 'OrthographicCamera') {
                    //floorplan要直接使用activeControl.camera，主要用到projectionMatrix
                    currentDis = (op.camera.right - op.camera.left) / op.camera.zoom / 3
                } else {
                    currentDis = op.position.distanceTo(op.camera.position) //dollhouse要直接使用player.camera, 因为activeControl.camera没有更新matrixWorld
                }

                if ((op.nearBound == void 0 && op.farBound != void 0) || (op.nearBound != void 0 && op.farBound == void 0)) {
                    //仅限制最大或最小的话，不判断像素大小，直接限制mesh的scale
                    //这个判断也可以写到getScaleForConstantSize里，可以更严谨控制像素宽度，这里只简单计算大小
                    let scale
                    if (op.farBound == void 0 && currentDis < op.nearBound) {
                        scale = (op.scale * currentDis) / op.nearBound
                    } else if (op.nearBound == void 0 && currentDis > op.farBound) {
                        scale = (op.scale * currentDis) / op.farBound
                    } else {
                        scale = op.scale
                    }
                    return scale
                }

                w = op.maxSize - (op.maxSize - op.minSize) * THREE.MathUtils.smoothstep(currentDis, op.nearBound, op.farBound)
                //maxSize ： mesh要表现的最大像素宽度；   nearBound： 最近距离，若比nearBound近，则使用maxSize
            }
            i.copy(op.position).project(op.camera), //tag中心在屏幕上的二维坐标
                o.set(op.dom.clientWidth / 2, op.dom.clientHeight / 2, 1).multiply(i), //转化成px   -w/2 到 w/2的范围
                l.set(w / 2, 0, 0).add(o), //加上tag宽度的一半
                c.set(2 / op.dom.clientWidth, 2 / op.dom.clientHeight, 1).multiply(l), //再转回  -1 到 1的范围
                h.copy(c).unproject(op.camera) //再转成三维坐标，求得tag边缘的位置
            var g = h.distanceTo(op.position) //就能得到tag的三维半径

            return g
        }
    })(),

    //W , H, left, top分别是rect的宽、高、左、上
    getCrossPointAtRect: function (p1, aim, W, H, left, top) {
        //求射线p1-aim在rect边界上的交点，其中aim在rect范围内，p1则不一定(交点在aim这边的延长线上)

        var x, y, borderX
        var r = (aim.x - p1.x) / (aim.y - p1.y) //根据相似三角形原理先求出这个比值
        var getX = function (y) {
            return r * (y - p1.y) + p1.x
        }
        var getY = function (x) {
            return (1 / r) * (x - p1.x) + p1.y
        }
        if (aim.x >= p1.x) {
            borderX = W + left
        } else {
            borderX = left
        }
        x = borderX
        y = getY(x)
        if (y < top || y > top + H) {
            if (y < top) {
                y = top
            } else {
                y = top + H
            }
            x = getX(y)
        }
        return new THREE.Vector2(x, y)
    },
    getDirFromUV: function (uv) {
        //获取dir   反向计算 - -  二维转三维比较麻烦
        var dirB //所求 单位向量

        uv.x %= 1
        if (uv.x < 0) uv.x += 1 //调整为0-1

        var y = Math.cos(uv.y * Math.PI) //uv中纵向可以直接确定y，  根据上面getUVfromDir的反向计算

        var angle = 2 * Math.PI * uv.x - Math.PI //x/z代表的是角度

        var axisX, axisZ //axis为1代表是正，-1是负数
        if (-Math.PI <= angle && angle < 0) {
            axisX = -1 //下半圆
        } else {
            axisX = 1 //上半圆
        }
        if (-Math.PI / 2 <= angle && angle < Math.PI / 2) {
            axisZ = 1 //右半圆
        } else {
            axisZ = -1 //左半圆
        }

        var XDivideZ = Math.tan(angle)
        var z = Math.sqrt((1 - y * y) / (1 + XDivideZ * XDivideZ))
        var x = XDivideZ * z

        if (z * axisZ < 0) {
            //异号
            z *= -1
            x *= -1
            if (x * axisX < 0) {
                //      console.log("wrong!!!!!??????????")
            }
        }

        x *= -1 //计算完成后这里不能漏掉 *= -1
        dirB = new THREE.Vector3(x, y, z)

        //理想状态下x和z和anotherDir相同
        return dirB
    },

    getUVfromDir: function (dir) {
        //获取UV  同shader里的计算
        var dir = dir.clone()
        dir.x *= -1 //计算前这里不能漏掉 *= -1  见shader
        var tx = Math.atan2(dir.x, dir.z) / (Math.PI * 2.0) + 0.5 //atan2(y,x) 返回从 X 轴正向逆时针旋转到点 (x,y) 时经过的角度。区间是-PI 到 PI 之间的值
        var ty = Math.acos(dir.y) / Math.PI
        return { x: tx, y: ty }

        //理想状态下tx相同
    },
    crossRight: function (vec3, matrix) {
        //向量右乘矩阵，不能用向量的applyMatrix4（左乘）
        var e = matrix.elements
        var v = new THREE.Vector3()
        v.x = e[0] * vec3.x + e[1] * vec3.y + e[2] * vec3.z + e[3]
        v.y = e[4] * vec3.x + e[5] * vec3.y + e[6] * vec3.z + e[7]
        v.z = e[8] * vec3.x + e[9] * vec3.y + e[10] * vec3.z + e[11]
        //v.w不要
        return v
    },
    getNormalDir: function (point, supportsTiles, currentPano) {
        //获取A单位法线
        /* console.log("lookVector:")
         console.log(objects.player.cameraControls.activeControl.lookVector) */

        var dir = point.clone().sub(currentPano.position) //OA
        /* console.log("A的dir（无matrix转化）:")
         console.log(dir.clone().normalize()); */

        if (supportsTiles) {
            var matrixWorld = currentPano.rot90Matrix.clone() //因为热点求点时所右乘的matrix必须是单张全景照片时用的转90度的matrix才行
        } else {
            var matrixWorld = currentPano.matrixWorld.clone()
        }
        dir = this.crossRight(dir, matrixWorld) //右乘matrixWorld 得matrix转化的向量
        dir.normalize()
        /* var b = player.currentPano.skyboxMesh.matrixWorld.clone().getInverse(player.currentPano.skyboxMesh.matrixWorld)
         console.log(crossRight(dir,b).normalize()) */

        return dir
    },
    getDirByLonLat: function (lon, lat) {
        var dir = new THREE.Vector3()
        var phi = THREE.MathUtils.degToRad(90 - lat)
        var theta = THREE.MathUtils.degToRad(lon)
        dir.x = Math.sin(phi) * Math.cos(theta)
        dir.y = Math.cos(phi)
        dir.z = Math.sin(phi) * Math.sin(theta)
        return dir
    }, //0,0 => (1,0,0)     270=>(0,0,-1)

    getLineIntersect2(o = {}) {
        //得两条直线在其向量构成的面的法线方向的交点，投影在线上点的中点。
        if (o.A != void 0) {
            // Ap1为一条线，Bp2为一条线
            var A = o.A
            var B = o.B
            var p1 = o.p1
            var p2 = o.p2

            var dir0 = o.dir0 || new THREE.Vector3().subVectors(p1, A)
            var dir1 = o.dir1 || new THREE.Vector3().subVectors(p2, B)
        }
        if (A.equals(B)) return { pos3d: p1.clone() }

        //寻找两个向量所在的面
        let normal = dir0.clone().cross(dir1) //面的法线

        //先把整体旋转到使在xz平面上，求完交点再转回来
        var qua = math.getQuaBetween2Vector(normal, new THREE.Vector3(0, 1, 0), new THREE.Vector3(0, 1, 0))

        let newPoints = [A, B, p1, p2].map(e => {
            return e.clone().applyQuaternion(qua)
        })

        var pos2d = math.isLineIntersect(
            [
                { x: newPoints[0].x, y: newPoints[0].z },
                { x: newPoints[2].x, y: newPoints[2].z },
            ],
            [
                { x: newPoints[1].x, y: newPoints[1].z },
                { x: newPoints[3].x, y: newPoints[3].z },
            ],
            true
        )
        var quaInverse = qua.clone().invert()

        let pos3d = new THREE.Vector3(pos2d.x, 0, pos2d.y)
        let pos3d1 = pos3d.clone().setY(newPoints[0].y)
        let pos3d2 = pos3d.clone().setY(newPoints[1].y)

        pos3d1.applyQuaternion(quaInverse)
        pos3d2.applyQuaternion(quaInverse)

        pos3d = new THREE.Vector3().addVectors(pos3d1, pos3d2).multiplyScalar(0.5)
        return { pos3d, mid1: pos3d1, mid2: pos3d2 }
    },

    getLineIntersect(o) {
        //两条三维直线相交 //取两线最短线段中心点  并且不能超出起点
        o = o || {}
        if (o.A != void 0) {
            // Ap1为一条线，Bp2为一条线
            var A = o.A
            var B = o.B
            var p1 = o.p1
            var p2 = o.p2
        }

        if (A.equals(B)) return { pos3d: p1.clone() }

        /* console.log("v1:")
        console.log(A.clone().sub(p1).normalize())
        console.log("v2:")
        console.log(B.clone().sub(p2).normalize())
         */

        //调试热点夹角
        var line1 = p1.clone().sub(A).normalize()
        var line2 = p2.clone().sub(B).normalize()
        var angle = line1.angleTo(line2)
        //var pano = player.model.panos.index[player.posGets.list[1]]
        //console.log('真实两线夹角: ', THREE.MathUtils.radToDeg(angle)) /*+ "旧夹角min: "+getAngle(pano.recentAngleScore)+"("+pano.recentAngleScore+")" */

        //----------

        var compute = function () {
            var pos3d
            var ux = p1.x - A.x
            var uy = p1.y - A.y
            var uz = p1.z - A.z

            var vx = p2.x - B.x
            var vy = p2.y - B.y
            var vz = p2.z - B.z

            var wx = A.x - B.x
            var wy = A.y - B.y
            var wz = A.z - B.z

            var a = ux * ux + uy * uy + uz * uz
            //u*u
            var b = ux * vx + uy * vy + uz * vz
            //u*v
            var c = vx * vx + vy * vy + vz * vz
            //v*v
            var d = ux * wx + uy * wy + uz * wz
            //u*w
            var e = vx * wx + vy * wy + vz * wz
            //v*w
            var dt = a * c - b * b

            var sd = dt
            var td = dt

            var sn = 0.0
            //sn = be-cd
            var tn = 0.0
            //tn = ae-bd

            var behind = function (index) {
                //在后方交点的话，直接其中一个点    不用两posget点中心点是因为可能从不同方位 距离很大
                pos3d = (index == 1 ? p1 : p2).clone()
                //console.log(pos3d , ' 在后方交点，使用点' + index)
            }.bind(this)

            if (math.closeTo(dt, 0.0)) {
                //两直线平行
                sn = 0.0
                //在s上指定取s0
                sd = 1.0
                //防止计算时除0错误
                tn = e
                //按(公式3)求tc
                td = c
            } else {
                sn = b * e - c * d
                tn = a * e - b * d
                if (sn < 0.0) {
                    //最近点在s起点以外，同平行条件
                    behind(1)
                    return { pos3d, behind: true }
                    sn = 0.0
                    tn = e
                    td = c
                } else if (sn > sd) {
                    //超出终点不限制
                    /* //最近点在s终点以外(即sc>1,则取sc=1)
                            sn = sd;
                            tn = e + b; //按(公式3)计算
                            td = c; */
                }
            }

            if (tn < 0.0) {
                //最近点在t起点以外
                behind(2)
                return { pos3d, behind: true }
                tn = 0.0
                if (-d < 0.0) sn = 0.0
                //按(公式2)计算，如果等号右边小于0，则sc也小于零，取sc=0
                else if (-d > a) sn = sd
                //按(公式2)计算，如果sc大于1，取sc=1
                else {
                    sn = -d
                    sd = a
                }
            }
            /*  else if (tn > td){   //超出终点不限制 
                    tn = td;
                    if ((-d + b) < 0.0)
                        sn = 0.0;
                    else if ((-d + b) > a)
                        sn = sd;
                    else
                    {
                        sn = (-d + b);
                        sd = a;
                    }
                } */

            var sc = 0.0
            var tc = 0.0

            if (math.closeTo(sn, 0.0)) sc = 0.0
            else sc = sn / sd
            if (math.closeTo(tn, 0.0)) tc = 0.0
            else tc = tn / td
            //两个最近点
            var mid1 = new THREE.Vector3(A.x + sc * ux, A.y + sc * uy, A.z + sc * uz)
            var mid2 = new THREE.Vector3(B.x + tc * vx, B.y + tc * vy, B.z + tc * vz)

            /* console.log("v11:")
            console.log(A.clone().sub(mid1).normalize())
            console.log("v22:")
            console.log(B.clone().sub(mid2).normalize()) */

            //console.log('另一个结果', math.getLineIntersect2(o)) //结果一样的，只是没有限制后方交点

            let r = { pos3d: mid1.clone().add(mid2).multiplyScalar(0.5), mid1, mid2 }
            return r
        }

        return compute()

        //https://blog.csdn.net/u011511587/article/details/52063663  三维空间两直线/线段最短距离、线段计算算法
    },

    getShapeGeo: function (points, holes) {
        //获取任意形状（多边形或弧形）的形状面  //quadraticCurveTo() 这是弧形的含函数
        var shape = new THREE.Shape()
        shape.moveTo(points[0].x, points[0].y)
        for (var i = 1, len = points.length; i < len; i++) {
            shape.lineTo(points[i].x, points[i].y)
        }

        /* var holePath = new THREE.Path()
				.moveTo( 20, 10 )
				.absarc( 10, 10, 10, 0, Math.PI * 2, true ) 
			arcShape.holes.push( holePath );
		 */
        if (holes) {
            //挖空
            holes.forEach(points => {
                var holePath = new THREE.Path()
                holePath.moveTo(points[0].x, points[0].y)
                for (var i = 1, len = points.length; i < len; i++) {
                    holePath.lineTo(points[i].x, points[i].y)
                }
                shape.holes.push(holePath)
            })
        }
        var geometry = new THREE.ShapeBufferGeometry(shape) //ShapeGeometry
        return geometry
    },
    getUnPosPlaneGeo: (function () {
        //获取还没有赋值位置的plane geometry
        var e = new Uint16Array([0, 1, 2, 0, 2, 3]),
            //	, t = new Float32Array([-.5, -.5, 0, .5, -.5, 0, .5, .5, 0, -.5, .5, 0])
            i = new Float32Array([0, 0, 1, 0, 1, 1, 0, 1]),
            g = new THREE.BufferGeometry()
        g.setIndex(new THREE.BufferAttribute(e, 1)),
            //g.setAttribute("position", new n.BufferAttribute(t, 3)),
            g.setAttribute('uv', new THREE.BufferAttribute(i, 2))
        return function () {
            return g
        }
    })(),
    getPlaneGeo: function (A, B, C, D) {
        var geo = this.getUnPosPlaneGeo().clone()
        var pos = new Float32Array([A.x, A.y, A.z, B.x, B.y, B.z, C.x, C.y, C.z, D.x, D.y, D.z])
        geo.setAttribute('position', new THREE.BufferAttribute(pos, 3))
        geo.computeVertexNormals()
        geo.computeBoundingSphere() //for raycaster
        return geo
    },
    drawPlane: function (A, B, C, D, material) {
        var wall = new THREE.Mesh(this.getPlaneGeo(A, B, C, D), material)
        return wall
    },
    movePlane: function (mesh, A, B, C, D) {
        var pos = new Float32Array([A.x, A.y, A.z, B.x, B.y, B.z, C.x, C.y, C.z, D.x, D.y, D.z])
        mesh.geometry.setAttribute('position', new THREE.BufferAttribute(pos, 3))
        mesh.geometry.computeBoundingSphere() //for checkIntersect
    },

    getAngle(vec1, vec2, axis) {
        var angle = vec1.angleTo(vec2)
        var axis_ = vec1.clone().cross(vec2)
        if (axis_[axis] < 0) {
            angle *= -1
        }
        return angle
    },

    linearClamp(value, x1, x2, y1, y2) {
        //x为bound.min, bound.max
        value = THREE.MathUtils.clamp(value, x1, x2)
        return y1 + ((y2 - y1) * (value - x1)) / (x2 - x1)
    },

    isInsideFrustum(bounding, camera) {
        // bounding是否在视野范围内有可见部分（视野就是一个锥状box）
        let frustumMatrix = new THREE.Matrix4()
        frustumMatrix.multiplyMatrices(camera.projectionMatrix, camera.matrixWorldInverse)

        let frustum = new THREE.Frustum()
        frustum.setFromProjectionMatrix(frustumMatrix)

        if (bounding instanceof THREE.Sphere) {
            return frustum.intersectsSphere(bounding)
        } else {
            return frustum.intersectsBox(bounding)
        }
    },

    getStandardYaw(yaw1, yaw2) {
        //使yaw1过渡到yaw2时朝角度差小的那边走。如果差距大于半个圆，就要反个方向转(把大的那个数字减去360度)
        if (Math.abs(yaw1 - yaw2) > Math.PI) {
            yaw1 > yaw2 ? (yaw1 -= Math.PI * 2) : (yaw2 -= Math.PI * 2)
        }
        return [yaw1, yaw2]
    },
}

export default math