three.js 原始碼註釋（十四）Math/Sphere.js
阿新 • • 發佈：2019-02-04
俺也是剛開始學,好多地兒肯定不對還請見諒.
以下程式碼是THREE.JS 原始碼檔案中Math/Sphere.js檔案的註釋.
// File:src/math/Sphere.js /** * @author bhouston / http://exocortex.com * @author mrdoob / http://mrdoob.com/ */ /* ///Sphere物件的建構函式.用來在三維空間內建立一個球體物件.Sphere物件的功能函式採用 ///定義構造的函式原型物件來實現. /// /// 用法: var center = new Vector3(0,0,0),radius = 5; var sphere = new Sphere(center,radius); ///建立一個圓心是0,0,0半徑是5的球體. */ ///<summary>Sphere</summary> ///<param name ="center" type="Vector3">中心點座標值</param> ///<param name ="radius" type="Number">Number球體半徑</param> THREE.Sphere = function ( center, radius ) { this.center = ( center !== undefined ) ? center : new THREE.Vector3(); //賦值或者初始化center this.radius = ( radius !== undefined ) ? radius : 0; //賦值或者初始化radius }; /**************************************** ****下面是Sphere物件提供的功能函式. ****************************************/ THREE.Sphere.prototype = { constructor: THREE.Sphere, //構造器,返回對建立此物件的Sphere函式的引用 /* ///set方法用來從新設定球體的起始點,結束點,center,radius座標值.並返回新半徑,座標值的球體. */ ///<summary>set</summary> ///<param name ="center" type="Vector3">中心點座標值</param> ///<param name ="radius" type="Number">Number球體半徑</param> ///<returns type="Sphere">返回新半徑,座標值的球體</returns> set: function ( center, radius ) { this.center.copy( center ); this.radius = radius; return this; //返回新半徑,座標值的球體 }, /* ///setFromPoints方法通過獲得Vector3物件組成的points陣列中的到圓心距離最大的值重新設定球體的半徑,通過可選引數optionalCenter用來設定球體的圓心.並返回新半徑,座標值的球體. /// NOTE:注意如果給setFromPoints()方法設定了optionalCenter引數,points陣列中數值到圓心的距離將會改變. */ ///<summary>setFromPoints</summary> ///<param name ="points" type="Vector3Array">Vector3物件組成的points陣列</param> ///<param name ="optionalCenter" type="Vector3">可選引數,接收返回結果,球體的中心點</param> ///<returns type="Sphere">返回新半徑,座標值的球體</returns> setFromPoints: function () { var box = new THREE.Box3(); return function ( points, optionalCenter ) { var center = this.center; if ( optionalCenter !== undefined ) { center.copy( optionalCenter ); } else { box.setFromPoints( points ).center( center ); } var maxRadiusSq = 0; for ( var i = 0, il = points.length; i < il; i ++ ) { maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( points[ i ] ) ); //求points陣列中到圓心的最大值並賦值給maxRadiusSq } this.radius = Math.sqrt( maxRadiusSq ); return this; //返回新半徑,座標值的球體 }; }(), /* ///copy方法用來複制球體的圓心,半徑,center,radius值.返回新半徑,座標值的球體 */ ///<summary>copy</summary> ///<param name ="sphere" type="Sphere">球體</param> ///<returns type="Sphere">返回新半徑,座標值的球體</returns> copy: function ( sphere ) { this.center.copy( sphere.center ); this.radius = sphere.radius; return this; //返回新半徑,座標值的球體 }, /* ///empty方法用來判斷球體的半徑是否小於等於0,用來判斷空間中半徑是0,或者小於0的球體. */ ///<summary>empty</summary> ///<returns type="Boolean">返回true 或者 false</returns> empty: function () { return ( this.radius <= 0 ); //返回true 或者 false }, /* ///containsPoint方法用來獲得引數point(一個Vector3的三維點座標)是否在當前球體內. */ ///<summary>containsPoint</summary> ///<param name ="point" type="Vector3">一個Vector3的三維點座標</param> ///<returns type="Boolean">返回true 或者 false</returns> containsPoint: function ( point ) { return ( point.distanceToSquared( this.center ) <= ( this.radius * this.radius ) ); //返回true 或者 false }, /* ///distanceToPoint方法用來獲得三維空間內一點到Sphere球體物件表面的最小長度. */ ///<summary>distanceToPoint</summary> ///<param name ="point" type="Vector3">一個三維空間內的Vector3的三維點座標</param> ///<returns type="Number">返回三維空間內一點到Sphere球體物件表面的最小長度.</returns> distanceToPoint: function ( point ) { return ( point.distanceTo( this.center ) - this.radius ); //返回三維空間內一點到Sphere球體物件表面的最小長度. }, /* ///intersectsSphere方法獲取當前球體是否與引數sphere球體物件相交,返回true 或者 false */ ///<summary>intersectsSphere</summary> ///<param name ="sphere" type="Sphere">一個Sphere的球體</param> ///<returns type="Boolean">返回true 或者 false</returns> intersectsSphere: function ( sphere ) { var radiusSum = this.radius + sphere.radius; return sphere.center.distanceToSquared( this.center ) <= ( radiusSum * radiusSum ); //返回true 或者 false }, /* ///clampPoint方法用來通過引數point收縮球體.如果point在球體外,強制將point設定到球體表面,如果point在球體內,重新設定球體半徑為point到當前球體半徑的距離. */ ///<summary>clampPoint</summary> ///<param name ="point" type="Vector3">一個Vector3的三維點座標</param> ///<param name ="optionalTarget" type="Vector3">可選引數,接收返回結果,返回剪裁過的邊界點</param> ///<returns type="Vector3">返回剪裁過的邊界點.</returns> clampPoint: function ( point, optionalTarget ) { var deltaLengthSq = this.center.distanceToSquared( point ); var result = optionalTarget || new THREE.Vector3(); result.copy( point ); if ( deltaLengthSq > ( this.radius * this.radius ) ) { result.sub( this.center ).normalize(); result.multiplyScalar( this.radius ).add( this.center ); } return result; // 返回剪裁過的邊界點 }, /* ///getBoundingBox方法返回當前球體的Box3立方體邊界(這裡應該外切於球體的一個立方體) /// 與Box3類中的getBoundingSphere()方法對應. */ ///<summary>getBoundingBox</summary> ///<param name ="optionalTarget" type="THREE.Box3()">可選引數,THREE.Box3()立方體物件,用來接收返回值</param> ///<returns type="THREE.Sphere()">返回當前球體的Box3立方體邊界(這裡應該外切於球體的一個立方體)</returns> getBoundingBox: function ( optionalTarget ) { var box = optionalTarget || new THREE.Box3(); box.set( this.center, this.center ); box.expandByScalar( this.radius ); return box; //返回當前球體的Box3立方體邊界(這裡應該外切於球體的一個立方體) }, /* ///applyMatrix4方法通過傳遞matrix(旋轉,縮放,移動等變換矩陣)對當前Sphere球體物件的圓心和半徑,應用變換. */ ///<summary>applyMatrix4</summary> ///<param name ="matrix" type="Matrix4">(旋轉,縮放,移動等變換矩陣</param> ///<returns type="Boolean">返回變換後的球體.</returns> applyMatrix4: function ( matrix ) { this.center.applyMatrix4( matrix ); this.radius = this.radius * matrix.getMaxScaleOnAxis(); return this; //返回變換後的球體. }, /* ///translate方法用來通過引數offset,移動當前球體的位置. */ ///<summary>translate</summary> ///<param name ="offset" type="Vector3">偏移量</param> ///<returns type="Boolean">返回新半徑,座標值的球體</returns> translate: function ( offset ) { this.center.add( offset ); return this; //返回新半徑,座標值的球體 }, /* ///equals方法用來獲得引數sphere(一個Sphere的球體)是否與當前球體完全相等,即圓心和半徑相等. */ ///<summary>equals</summary> ///<param name ="sphere" type="Sphere">一個Sphere的球體</param> ///<returns type="Boolean">返回true 或者 false</returns> equals: function ( sphere ) { return sphere.center.equals( this.center ) && ( sphere.radius === this.radius ); //返回true 或者 false }, /*clone方法 ///clone方法克隆一個球體物件. */ ///<summary>clone</summary> ///<returns type="Sphere">返回球體物件</returns> clone: function () { return new THREE.Sphere().copy( this ); //返回球體物件 } };
以下程式碼是THREE.JS 原始碼檔案中Math/Line3.js檔案的註釋.