商域无疆 (http://blog.csdn.net/omni360/)
本文遵循“署名-非商业用途-保持一致”创作公用协议
转载请保留此句：商域无疆 - 本博客专注于敏捷开发及移动和物联设备研究：数据可视化、GOLANG、Html5、WEBGL、THREE.JS，否则，出自本博客的文章拒绝转载或再转载，谢谢合作。
俺也是刚开始学,好多地儿肯定不对还请见谅.
以下代码是THREE.JS 源码文件中extras/geometries/PolyhedronGeometry.js文件的注释.
更多更新在 :https://github.com/omni360/three.js.sourcecode
/** * @author clockworkgeek / https://github.com/clockworkgeek * @author timothypratley / https://github.com/timothypratley * @author WestLangley / http://github.com/WestLangley*//*///PolyhedronGeometry用来在三维空间内创建一个多面体对象,二十面体,八面体,四面体都会调用当前对象.//////用法: /// var vertices = [ 1, 1, 1, - 1, - 1, 1, - 1, 1, - 1, 1, - 1, - 1 ];/// var indices = [ 2, 1, 0, 0, 3, 2, 1, 3, 0, 2, 3, 1 ];/// var geometry = new THREE.PolyhedronGeometry(vertices,indices,70);/// var material = new THREE.MeshBasicMaterial({color: 0x00ff00});/// var icos = new THREE.Mesh(geometry,material);/// scene.add(icos);*////<summary>PolyhedronGeometry</summary>///<param name ="vertices" type="float">多面体顶点数组</param>///<param name ="indices" type="float">多面体顶点索引顺序</param>///<param name ="radius" type="float">多面体半径,默认初始化为1</param>///<param name ="detail" type="float">细节因子,默认为0,当超过0将会有更多的顶点,当前的几何体就不会是多面体,当参数detail大于1,将会变成一个球体.</param>THREE.PolyhedronGeometry = function ( vertices, indices, radius, detail ) {THREE.Geometry.call( this );//调用Geometry对象的call方法,将原本属于Geometry的方法交给当前对象PolyhedronGeometry来使用.radius = radius || 1;//多面体半径,默认初始化为1detail = detail || 0;//细节因子,默认为0,当超过0将会有更多的顶点,当前的几何体就不会是多面体,当参数detail大于1,将会变成一个球体.var that = this;//计算顶点数据,压入vertices数组.for ( var i = 0, l = vertices.length; i < l; i += 3 ) {prepare( new THREE.Vector3( vertices[ i ], vertices[ i + 1 ], vertices[ i + 2 ] ) );}var midpoints = [], p = this.vertices;var faces = [];//计算三角面.for ( var i = 0, j = 0, l = indices.length; i < l; i += 3, j ++ ) {var v1 = p[ indices[ i ] ];var v2 = p[ indices[ i + 1 ] ];var v3 = p[ indices[ i + 2 ] ];faces[ j ] = new THREE.Face3( v1.index, v2.index, v3.index, [ v1.clone(), v2.clone(), v3.clone() ] );}var centroid = new THREE.Vector3();for ( var i = 0, l = faces.length; i < l; i ++ ) {subdivide( faces[ i ], detail );}// Handle case when face straddles the seam// 处理当面横跨缝合线的特殊情况for ( var i = 0, l = this.faceVertexUvs[ 0 ].length; i < l; i ++ ) {var uvs = this.faceVertexUvs[ 0 ][ i ];var x0 = uvs[ 0 ].x;var x1 = uvs[ 1 ].x;var x2 = uvs[ 2 ].x;var max = Math.max( x0, Math.max( x1, x2 ) );var min = Math.min( x0, Math.min( x1, x2 ) );if ( max > 0.9 && min < 0.1 ) { // 0.9 is somewhat arbitraryif ( x0 < 0.2 ) uvs[ 0 ].x += 1;if ( x1 < 0.2 ) uvs[ 1 ].x += 1;if ( x2 < 0.2 ) uvs[ 2 ].x += 1;}}// Apply radius// 对顶点应用位置,乘以半径值.for ( var i = 0, l = this.vertices.length; i < l; i ++ ) {this.vertices[ i ].multiplyScalar( radius );}// Merge vertices 合并顶点this.mergeVertices();//去除多余的顶点this.computeFaceNormals();//计算面的法线this.boundingSphere = new THREE.Sphere( new THREE.Vector3(), radius );//计算球体边界/*///prepare是计算顶点位置的具体实现,将传入的向量(参数Vector3)投影到球体的表面*////<summary>prepare</summary>///<param name ="radius" type="Vector3"></param>///<return type="Vector3">球体体半径</param>// Project vector onto sphere's surface// 投影矢量到球体的表面.function prepare( vector ) {var vertex = vector.normalize().clone();vertex.index = that.vertices.push( vertex ) - 1;// Texture coords are equivalent to map coords, calculate angle and convert to fraction of a circle.// 纹理坐标等于贴图uv坐标,计算角度并转换为圆的一部分.var u = azimuth( vector ) / 2 / Math.PI + 0.5;var v = inclination( vector ) / Math.PI + 0.5;vertex.uv = new THREE.Vector2( u, 1 - v );return vertex;//返回对应的顶点}/*///make是细分曲面的具体实现,递归计算曲面顶点,转换为细分的三角形*////<summary>make</summary>///<param name ="v1" type="Vector3">三角形的第一个顶点</param>///<param name ="v2" type="Vector3">三角形的第二个顶点</param>///<param name ="v3" type="Vector3">三角形的第三个顶点</param>// Approximate a curved face with recursively sub-divided triangles.//递归计算曲面顶点,转换为细分的三角形.function make( v1, v2, v3 ) {var face = new THREE.Face3( v1.index, v2.index, v3.index, [ v1.clone(), v2.clone(), v3.clone() ] );that.faces.push( face );centroid.copy( v1 ).add( v2 ).add( v3 ).divideScalar( 3 );var azi = azimuth( centroid );that.faceVertexUvs[ 0 ].push( [correctUV( v1.uv, v1, azi ),correctUV( v2.uv, v2, azi ),correctUV( v3.uv, v3, azi )] );}/*///make是细分曲面的具体实现,递归计算曲面顶点,转换为细分的三角形*////<summary>make</summary>///<param name ="face" type="Face3">三角面</param>///<param name ="detail" type="float">细节因子,默认为0,当超过0将会有更多的顶点,当前的几何体就不会是多面体,当参数detail大于1,将会变成一个球体</param>// Analytically subdivide a face to the required detail level.//按照要求的细节因子,细分三角面.function subdivide( face, detail ) {var cols = Math.pow(2, detail);var cells = Math.pow(4, detail);var a = prepare( that.vertices[ face.a ] );var b = prepare( that.vertices[ face.b ] );var c = prepare( that.vertices[ face.c ] );var v = [];// Construct all of the vertices for this subdivision.// 构建所有的细分三角形顶点.for ( var i = 0 ; i <= cols; i ++ ) {v[ i ] = [];var aj = prepare( a.clone().lerp( c, i / cols ) );var bj = prepare( b.clone().lerp( c, i / cols ) );var rows = cols - i;for ( var j = 0; j <= rows; j ++) {if ( j == 0 && i == cols ) {v[ i ][ j ] = aj;} else {v[ i ][ j ] = prepare( aj.clone().lerp( bj, j / rows ) );}}}// Construct all of the faces.// 构建所有的三角面for ( var i = 0; i < cols ; i ++ ) {for ( var j = 0; j < 2 * (cols - i) - 1; j ++ ) {var k = Math.floor( j / 2 );if ( j % 2 == 0 ) {make(v[ i ][ k + 1],v[ i + 1 ][ k ],v[ i ][ k ]);} else {make(v[ i ][ k + 1 ],v[ i + 1][ k + 1],v[ i + 1 ][ k ]);}}}}/*///azimuth方法获得一个点当从上面看时,绕y轴的角度.*////<summary>azimuth</summary>///<param name ="vector" type="Vector3">三维向量</param>// Angle around the Y axis, counter-clockwise when looking from above.// 当从上面看时,绕y轴的角度.function azimuth( vector ) {return Math.atan2( vector.z, - vector.x );}/*///inclination方法获得一个点在xz平面上的角度.*////<summary>inclination</summary>///<param name ="vector" type="Vector3">三维向量</param>// Angle above the XZ plane.// 获得一个点在xz平面上的角度.function inclination( vector ) {return Math.atan2( - vector.y, Math.sqrt( ( vector.x * vector.x ) + ( vector.z * vector.z ) ) );}/*///inclination方法获得一个点在xz平面上的角度.*////<summary>inclination</summary>///<param name ="uv" type="Vector2">二维向量</param>///<param name ="vector" type="Vector3">三维向量</param>///<param name ="azimuth" type="Vector3">一个点当从上面看时,绕y轴的角度</param>// Texture fixing helper. Spheres have some odd behaviours.// 纹理替换辅助器,因为多面体表面和球体相比有一些奇怪的棱角,这里为了让纹理更好的适配多面体表面.function correctUV( uv, vector, azimuth ) {if ( ( azimuth < 0 ) && ( uv.x === 1 ) ) uv = new THREE.Vector2( uv.x - 1, uv.y );if ( ( vector.x === 0 ) && ( vector.z === 0 ) ) uv = new THREE.Vector2( azimuth / 2 / Math.PI + 0.5, uv.y );return uv.clone();}};/*****************************************************下面是PolyhedronGeometry对象的方法属性定义,继承自Geometry对象.**************************************************/THREE.PolyhedronGeometry.prototype = Object.create( THREE.Geometry.prototype );
商域无疆 (http://blog.csdn.net/omni360/)
本文遵循“署名-非商业用途-保持一致”创作公用协议
转载请保留此句：商域无疆 - 本博客专注于敏捷开发及移动和物联设备研究：数据可视化、GOLANG、Html5、WEBGL、THREE.JS，否则，出自本博客的文章拒绝转载或再转载，谢谢合作。
以下代码是THREE.JS 源码文件中extras/geometries/PolyhedronGeometry.js文件的注释.
更多更新在 :https://github.com/omni360/three.js.sourcecode