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Math/Ray.js文件的注释.
更多更新在 : https://github.com/omni360/three.js.sourcecode/blob/master/Three.js
今天把Three.js的Ray类注释完了,非常重要的一个类.在场景中拾取对象,经常会用到这个类.
// File:src/math/Ray.js
/**
* @author bhouston / http://exocortex.com
*/
/*
///Ray对象的构造函数.用来创建一个三维空间里的射线对象.Ray对象的功能函数采用
///定义构造的函数原型对象来实现,ray主要是用来进行碰撞检测,在选择场景中的对象时经常会用到,判断当前鼠标是否与对象重合用来选择对象.
///
/// 用法: var origin = new Vector3(1,1,1),direction = new Vector3(9,9,9); var ray = new Ray(origin,direction);
/// 创建一个原点为origin,方向为direction的射线.
*/
///<summary>Ray</summary>
///<param name ="origin" type="Vector3">射线的端点,Vector3对象</param>
///<param name ="direction" type="Vector3">射线的方向,Vector3对象</param>
THREE.Ray = function ( origin, direction ) {
this.origin = ( origin !== undefined ) ? origin : new THREE.Vector3();
this.direction = ( direction !== undefined ) ? direction : new THREE.Vector3();
};
/****************************************
****下面是Vector3对象提供的功能函数.
****************************************/
THREE.Ray.prototype = {
constructor: THREE.Ray, //构造器,返回对创建此对象的Ray函数的引用
/*
///set方法用来从新设置射线的端点和方向(origin,direction).并返回新的射线.
*/
///<summary>set</summary>
///<param name ="origin" type="Vector3">x坐标</param>
///<param name ="direction" type="Vector3">y坐标</param>
///<returns type="Ray">返回新的射线</returns>
set: function ( origin, direction ) {
this.origin.copy( origin );
this.direction.copy( direction );
return this; //返回新的射线
},
/*
///copy方法用来复制射线的端点,方向,origin,direction坐标值.并返回新的坐标值的射线.
*/
///<summary>copy</summary>
///<param name ="ray" type="Ray">射线</param>
///<returns type="Ray">返回新坐标值的射线</returns>
copy: function ( ray ) {
this.origin.copy( ray.origin );
this.direction.copy( ray.direction );
return this; //返回新坐标值的射线
},
/*
///at方法将返回沿当前射线方向的从端点起长度为t的点.如果传入了optionalTarget参数,将结果保存到optionalTarget中.
/// NOTE:optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象
*/
///<summary>at</summary>
///<param name ="t" type="Number">数值,到端点的长度</param>
///<param name ="optionalTarget" type="Vector3">optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象</param>
///<returns type="Ray">返回沿当前射线方向的从端点起长度为t的点/returns>
at: function ( t, optionalTarget ) {
var result = optionalTarget || new THREE.Vector3();
return result.copy( this.direction ).multiplyScalar( t ).add( this.origin ); //将返回沿当前射线方向的从端点起长度为t的点
},
/*
///recast方法将调用at(t)方法返回沿当前射线方向的从端点起长度为t的点,并将范围的点设为端点.
*/
///<summary>recast</summary>
///<param name ="t" type="Number">数值,到端点的长度</param>
///<returns type="Ray">返回新端点的射线/returns>
recast: function () {
var v1 = new THREE.Vector3();
return function ( t ) {
this.origin.copy( this.at( t, v1 ) ); //调用at(t)方法返回沿当前射线方向的从端点起长度为t的点,并将范围的点设为端点.
return this; //返回新端点的射线
};
}(),
/*
///closestPointToPoint方法将返回任意点point到射线上的垂足.如果传入了optionalTarget参数,将结果保存到optionalTarget中.
/// NOTE:optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象
/// NOTE:注意closestPointToPoint()方法定义如果垂足不在射线上,返回原点.
*/
///<summary>closestPointToPoint</summary>
///<param name ="point" type="Vector3">任意点Vector3对象</param>
///<param name ="optionalTarget" type="Vector3">optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象</param>
///<returns type="Ray">返回任意点point到射线上的垂足/returns>
closestPointToPoint: function ( point, optionalTarget ) {
var result = optionalTarget || new THREE.Vector3();
result.subVectors( point, this.origin );
var directionDistance = result.dot( this.direction ); //调用dot方法返回两个向量的点积,并赋值给directionDistance.
if ( directionDistance < 0 ) { //如果directionDistance小于0,表示垂足不在射线上,
return result.copy( this.origin ); //返回原点
}
return result.copy( this.direction ).multiplyScalar( directionDistance ).add( this.origin ); //返回任意点point到射线上的垂足
},
/*
///distanceToPoint方法将返回任意点到该射线的距离.
/// NOTE:注意distanceToPoint()方法定义如果传入的参数point在端点后面,返回端点到该点的距离.
*/
///<summary>distanceToPoint</summary>
///<param name ="point" type="Vector3">任意点Vector3对象</param>
///<returns type="Number">返回任意点point到射线的距离或到射线端点的距离./returns>
distanceToPoint: function () {
var v1 = new THREE.Vector3();
return function ( point ) {
var directionDistance = v1.subVectors( point, this.origin ).dot( this.direction ); //调用dot方法返回两个向量的点积,并赋值给directionDistance.
// point behind the ray
// 判断端点是否在端点后面
if ( directionDistance < 0 ) { //如果directionDistance小于0,表示参数point在射线端点后面
return this.origin.distanceTo( point ); //返回端点到该点的距离
}
v1.copy( this.direction ).multiplyScalar( directionDistance ).add( this.origin ); //如果参数point在射线端点前面,
return v1.distanceTo( point ); //返回该点到射线的距离,即到垂足的距离.
};
}(),
/*
///distanceSqToSegment方法将返回有参数v0,v1组成的线段到当前射线的最小距离.可选参数optionalPointOnRay, optionalPointOnSegment,分别用来存储在射线上和在线段上的垂足.
*/
///<summary>distanceToPoint</summary>
///<param name ="v0" type="Vector3">任意点Vector3对象</param>
///<param name ="v1" type="Vector3">任意点Vector3对象</param>
///<param name ="optionalPointOnRay" type="Vector3">optionalPointOnRay是可选参数,如果没有设置,系统自动创建一个临时Vector3对象,用来存储在射线上的垂足</param>
///<param name ="optionalPointOnSegment" type="Vector3">optionalPointOnSegment是可选参数,如果没有设置,系统自动创建一个临时Vector3对象,用来存储在线段上的垂足</param>
///<returns type="Number">返回任意点point到射线的距离或到射线端点的距离./returns>
distanceSqToSegment: function ( v0, v1, optionalPointOnRay, optionalPointOnSegment ) {
// from http://www.geometrictools.com/LibMathematics/Distance/Wm5DistRay3Segment3.cpp
// It returns the min distance between the ray and the segment
// distanceSqToSegment()方法返回线段到当前射线的最小距离
// defined by v0 and v1
// 线段由v0,v1构成
// It can also set two optional targets :
// 可一传递两个可选参数optionalPointOnRay, optionalPointOnSegment
// - The closest point on the ray
// 参数optionalPointOnRay用来存储在射线上的垂足
// - The closest point on the segment
// 参数optionalPointOnSegment用来存储在线段上的垂足
var segCenter = v0.clone().add( v1 ).multiplyScalar( 0.5 ); //获得线段的中点
var segDir = v1.clone().sub( v0 ).normalize(); //获得线段的单位向量,
var segExtent = v0.distanceTo( v1 ) * 0.5; //线段的长度的一半?
var diff = this.origin.clone().sub( segCenter ); //
var a01 = - this.direction.dot( segDir );
var b0 = diff.dot( this.direction );
var b1 = - diff.dot( segDir );
var c = diff.lengthSq();
var det = Math.abs( 1 - a01 * a01 );
var s0, s1, sqrDist, extDet;
if ( det >= 0 ) {
// The ray and segment are not parallel.
// 线段和射线不平行
s0 = a01 * b1 - b0;
s1 = a01 * b0 - b1;
extDet = segExtent * det;
if ( s0 >= 0 ) {
if ( s1 >= - extDet ) {
if ( s1 <= extDet ) {
// region 0
// Minimum at interior points of ray and segment.
var invDet = 1 / det;
s0 *= invDet;
s1 *= invDet;
sqrDist = s0 * ( s0 + a01 * s1 + 2 * b0 ) + s1 * ( a01 * s0 + s1 + 2 * b1 ) + c;
} else {
// region 1
s1 = segExtent;
s0 = Math.max( 0, - ( a01 * s1 + b0 ) );
sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;
}
} else {
// region 5
s1 = - segExtent;
s0 = Math.max( 0, - ( a01 * s1 + b0 ) );
sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;
}
} else {
if ( s1 <= - extDet ) {
// region 4
s0 = Math.max( 0, - ( - a01 * segExtent + b0 ) );
s1 = ( s0 > 0 ) ? - segExtent : Math.min( Math.max( - segExtent, - b1 ), segExtent );
sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;
} else if ( s1 <= extDet ) {
// region 3
s0 = 0;
s1 = Math.min( Math.max( - segExtent, - b1 ), segExtent );
sqrDist = s1 * ( s1 + 2 * b1 ) + c;
} else {
// region 2
s0 = Math.max( 0, - ( a01 * segExtent + b0 ) );
s1 = ( s0 > 0 ) ? segExtent : Math.min( Math.max( - segExtent, - b1 ), segExtent );
sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;
}
}
} else {
// Ray and segment are parallel.
// 线段和射线平行
s1 = ( a01 > 0 ) ? - segExtent : segExtent;
s0 = Math.max( 0, - ( a01 * s1 + b0 ) );
sqrDist = - s0 * s0 + s1 * ( s1 + 2 * b1 ) + c;
}
if ( optionalPointOnRay ) {
optionalPointOnRay.copy( this.direction.clone().multiplyScalar( s0 ).add( this.origin ) );
}
if ( optionalPointOnSegment ) {
optionalPointOnSegment.copy( segDir.clone().multiplyScalar( s1 ).add( segCenter ) );
}
return sqrDist; //返回最小长度.
},
/*
///isIntersectionSphere方法用来判断当前射线是否与参数sphere球体相交相交.
/// NOTE:isIntersectionSphere方法要求Sphere球体对象,必须有radius和center属性,sphereGeometry无效
*/
///<summary>isIntersectionSphere</summary>
///<param name ="sphere" type="Sphere">Sphere球体对象,必须有radius和center属性,sphereGeometry无效</param>
///<returns type="Boolean">返回true 或者 false</returns>
isIntersectionSphere: function ( sphere ) {
return this.distanceToPoint( sphere.center ) <= sphere.radius; //返回true 或者 false
},
/*
///intersectSphere方法用来判断当前射线是否与参数sphere球体相交,如果相交返回交点.如果不想交返回null
/// NOTE:intersectSphere方法要求Sphere球体对象,必须有radius和center属性,sphereGeometry无效
/// NOTE:intersectSphere方法经常用在鼠标拾取球体
*/
///<summary>intersectSphere</summary>
///<param name ="sphere" type="Sphere">Sphere球体对象,必须有radius和center属性,sphereGeometry无效</param>
///<param name ="optionalTarget" type="Vector3">optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象,用来存储射线与球体的交点</param>
///<returns type="Boolean">如果相交返回交点.如果不想交返回null</returns>
intersectSphere: function () {
// from http://www.scratchapixel.com/lessons/3d-basic-lessons/lesson-7-intersecting-simple-shapes/ray-sphere-intersection/
var v1 = new THREE.Vector3();
return function ( sphere, optionalTarget ) {
v1.subVectors( sphere.center, this.origin );
var tca = v1.dot( this.direction );
var d2 = v1.dot( v1 ) - tca * tca;
var radius2 = sphere.radius * sphere.radius;
if ( d2 > radius2 ) return null; //如果不相交返回null
var thc = Math.sqrt( radius2 - d2 );
// t0 = first intersect point - entrance on front of sphere
// t0射线与球体的第一个交点,从球体的前面进入
var t0 = tca - thc;
// t1 = second intersect point - exit point on back of sphere
// t1射线与球体的第二个交点,从球体的背面射出
var t1 = tca + thc;
// test to see if both t0 and t1 are behind the ray - if so, return null
// 如果t0,t1都小于0,说明球体在射线端点的后面,返回null.
if ( t0 < 0 && t1 < 0 ) return null;
// test to see if t0 is behind the ray:
// 如果t0射线与球体的第一个交点在射线端点的后面,
// if it is, the ray is inside the sphere, so return the second exit point scaled by t1,
// 说明射线端点在球体的内部,所以返回射线与球体表面的交点是t1,从球体的背面射出的交点.
// in order to always return an intersect point that is in front of the ray.
// 一般情况下总是返回一个交点,这里返回的是从球体的背面射出的交点.
if ( t0 < 0 ) return this.at( t1, optionalTarget );
// else t0 is in front of the ray, so return the first collision point scaled by t0
// 另一种情况,球体在射线的前面,返回t0,射线从球体体正面射入的交点.
return this.at( t0, optionalTarget );
}
}(),
/*
///isIntersectionPlane方法用来判断当前射线是否与参数Plane平面相交,经常用来判断用户是否选中了场景中的平面.
/// NOTE:isIntersectionPlane方法要求Plane平面对象,必须有normal属性
*/
///<summary>isIntersectionPlane</summary>
///<param name ="plane" type="Plane">Plane平面对象,必须有normal属性</param>
///<returns type="Boolean">返回true 或者 false</returns>
isIntersectionPlane: function ( plane ) {
// check if the ray lies on the plane first
// 检查射线原点是否在Plane平面上,
var distToPoint = plane.distanceToPoint( this.origin ); //获得平面到射线原点(就是鼠标所在位置)的距离
if ( distToPoint === 0 ) { //如果在平面上
return true; //返回true
}
var denominator = plane.normal.dot( this.direction ); //调用normal.dot方法获得射线到平面法线的单位向量,并赋值给denominator
if ( denominator * distToPoint < 0 ) { //原点到平面的距离乘以单位向量小于0,说明平面在射线的前面.
return true; //返回true
}
// ray origin is behind the plane (and is pointing behind it)
// 射线原点在Plane平面的后面,
return false; //返回false
},
/*
///distanceToPlane方法将返回参数plane平面到当前射线的最小距离.
/// NOTE:distanceToPlane方法要求Plane平面对象,必须有normal属性
*/
///<summary>distanceToPlane</summary>
///<param name ="plane" type="Plane">Plane平面对象,必须有normal属性</param>
///<returns type="Number">返回任意点point到射线的距离或到射线端点的距离t,如果射线在当前平面上返回0.射线与平面永不相交或其他未知定义返回null</returns>
distanceToPlane: function ( plane ) {
var denominator = plane.normal.dot( this.direction );
if ( denominator == 0 ) {
// line is coplanar, return origin
// 射线和平面共面,返回原点0.
if ( plane.distanceToPoint( this.origin ) == 0 ) {
return 0; //如果射线在当前平面上返回0
}
// Null is preferable to undefined since undefined means.... it is undefined
// 其他未知定义返回null
return null; //其他未知定义返回null
}
var t = - ( this.origin.dot( plane.normal ) + plane.constant ) / denominator;
// Return if the ray never intersects the plane
// 射线与平面永不相交返回null
return t >= 0 ? t : null; //射线与平面永不相交返回null,或者返回距离t
},
/*
///intersectPlane方法用来判断当前射线是否与参数plane平面相交,如果相交返回交点.如果不想交返回null
/// NOTE:intersectSphere方法要求plane平面对象,必须有normal属性
/// NOTE:intersectSphere方法经常用在鼠标拾取plane平面
*/
///<summary>intersectPlane</summary>
///<param name ="plane" type="Plane">Plane平面对象,必须有normal属性</param>
///<param name ="optionalTarget" type="Vector3">optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象,用来存储射线与平面的交点</param>
///<returns type="Boolean">如果相交返回交点.如果射线与平面永不相交或其他未知定义返回null</returns>
intersectPlane: function ( plane, optionalTarget ) {
var t = this.distanceToPlane( plane ); //调用distanceToPlane方法将返回参数plane平面到当前射线的最小距离
if ( t === null ) { //如果射线与平面永不相交或其他未知定义返回null
return null; //返回null
}
return this.at( t, optionalTarget ); //如果相交返回交点
},
/*
///isIntersectionBox方法用来判断当前射线是否与参数Box立方体相交,经常用来判断用户是否选中了场景中的Box立方体对象.
/// NOTE:isIntersectionPlane方法要求Box立方体对象,必须有min,max属性
*/
///<summary>isIntersectionBox</summary>
///<param name ="box" type="Box3">Box立方体对象,必须有min,max属性</param>
///<returns type="Boolean">返回true 或者 false</returns>
isIntersectionBox: function () {
var v = new THREE.Vector3();
return function ( box ) {
return this.intersectBox( box, v ) !== null; //调用intersectBox()方法,判断是否不等于null,返回true 或者 false
};
}(),
/*
///intersectBox方法用来判断当前射线是否与参数Box立方体相交,如果相交返回交点.如果不想交返回null
/// NOTE:intersectBox方法要求Box立方体对象,必须有min,max属性
/// NOTE:intersectBox方法经常用在鼠标拾取Box立方体
*/
///<summary>intersectBox</summary>
///<param name ="box" type="Box3">Box立方体对象,必须有min,max属性</param>
///<param name ="optionalTarget" type="Vector3">optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象,用来存储射线与立方体的交点</param>
///<returns type="Boolean">如果相交返回交点.如果射线与Box立方体永不相交或其他未知定义返回null</returns>
intersectBox: function ( box , optionalTarget ) {
// http://www.scratchapixel.com/lessons/3d-basic-lessons/lesson-7-intersecting-simple-shapes/ray-box-intersection/
var tmin,tmax,tymin,tymax,tzmin,tzmax;
var invdirx = 1 / this.direction.x,
invdiry = 1 / this.direction.y,
invdirz = 1 / this.direction.z;
var origin = this.origin;
//下面的这些是判断射线的原点在立方体的前后左右,还是立方体内,还是永不相交.如果射线原点在立方体后面或者不相交,返回null
if ( invdirx >= 0 ) {
tmin = ( box.min.x - origin.x ) * invdirx;
tmax = ( box.max.x - origin.x ) * invdirx;
} else {
tmin = ( box.max.x - origin.x ) * invdirx;
tmax = ( box.min.x - origin.x ) * invdirx;
}
if ( invdiry >= 0 ) {
tymin = ( box.min.y - origin.y ) * invdiry;
tymax = ( box.max.y - origin.y ) * invdiry;
} else {
tymin = ( box.max.y - origin.y ) * invdiry;
tymax = ( box.min.y - origin.y ) * invdiry;
}
if ( ( tmin > tymax ) || ( tymin > tmax ) ) return null;
// These lines also handle the case where tmin or tmax is NaN
// (result of 0 * Infinity). x !== x returns true if x is NaN
if ( tymin > tmin || tmin !== tmin ) tmin = tymin;
if ( tymax < tmax || tmax !== tmax ) tmax = tymax;
if ( invdirz >= 0 ) {
tzmin = ( box.min.z - origin.z ) * invdirz;
tzmax = ( box.max.z - origin.z ) * invdirz;
} else {
tzmin = ( box.max.z - origin.z ) * invdirz;
tzmax = ( box.min.z - origin.z ) * invdirz;
}
if ( ( tmin > tzmax ) || ( tzmin > tmax ) ) return null;
if ( tzmin > tmin || tmin !== tmin ) tmin = tzmin;
if ( tzmax < tmax || tmax !== tmax ) tmax = tzmax;
//return point closest to the ray (positive side)
//返回射线到立方体的垂足(正面的).
if ( tmax < 0 ) return null;
return this.at( tmin >= 0 ? tmin : tmax, optionalTarget ); //返回交点并设置给可选参数optionalTarget
},
/*
///intersectTriangle方法用来判断当前射线是否与参数a,b,c组成的Triangle三角形对象相交,如果相交返回交点.如果不想交返回null
/// NOTE:intersectTriangle方法要求Box立方体对象,必须有min,max属性
/// NOTE:intersectTriangle方法经常用在鼠标拾取Triangle三角形
/// NOTE:可以参考博客http://www.cnblogs.com/graphics/archive/2010/08/09/1795348.html
*/
///<summary>intersectTriangle</summary>
///<param name ="a" type="Vector3">Triangle三角形的角点a</param>
///<param name ="b" type="Vector3">Triangle三角形的角点b</param>
///<param name ="c" type="Vector3">Triangle三角形的角点c</param>
///<param name ="backfaceCulling" type="Boolean">true 或者 false,用来表示是否选择背面</param>
///<param name ="optionalTarget" type="Vector3">optionalTarget是可选参数,如果没有设置,系统自动创建一个临时Vector3对象,用来存储射线与立方体的交点</param>
///<returns type="Boolean">如果相交返回交点.如果射线与Triangle三角形永不相交或其他未知定义返回null</returns>
intersectTriangle: function () {
// Compute the offset origin, edges, and normal.
var diff = new THREE.Vector3();
var edge1 = new THREE.Vector3();
var edge2 = new THREE.Vector3();
var normal = new THREE.Vector3();
return function ( a, b, c, backfaceCulling, optionalTarget ) {
// from http://www.geometrictools.com/LibMathematics/Intersection/Wm5IntrRay3Triangle3.cpp
edge1.subVectors( b, a );
edge2.subVectors( c, a );
normal.crossVectors( edge1, edge2 );
// Solve Q + t*D = b1*E1 + b2*E2 (Q = kDiff, D = ray direction,
// E1 = kEdge1, E2 = kEdge2, N = Cross(E1,E2)) by
// |Dot(D,N)|*b1 = sign(Dot(D,N))*Dot(D,Cross(Q,E2))
// |Dot(D,N)|*b2 = sign(Dot(D,N))*Dot(D,Cross(E1,Q))
// |Dot(D,N)|*t = -sign(Dot(D,N))*Dot(Q,N)
var DdN = this.direction.dot( normal );
var sign;
//下面的这些是判断射线的原点在Triangle三角形的前后左右,还是立方体内,还是永不相交.如果射线原点在立方体后面或者不相交,返回null
if ( DdN > 0 ) {
if ( backfaceCulling ) return null;
sign = 1;
} else if ( DdN < 0 ) {
sign = - 1;
DdN = - DdN;
} else {
return null;
}
diff.subVectors( this.origin, a );
var DdQxE2 = sign * this.direction.dot( edge2.crossVectors( diff, edge2 ) );
// b1 < 0, no intersection
// b1 <0 ,不相交
if ( DdQxE2 < 0 ) {
return null;
}
var DdE1xQ = sign * this.direction.dot( edge1.cross( diff ) );
// b2 < 0, no intersection
// b2 <0 ,不相交
if ( DdE1xQ < 0 ) {
return null;
}
// b1+b2 > 1, no intersection
// b1+b2 > 1 ,不相交
if ( DdQxE2 + DdE1xQ > DdN ) {
return null;
}
// Line intersects triangle, check if ray does.
// 射线与三角形相交
var QdN = - sign * diff.dot( normal );
// t < 0, no intersection
// t < 0, 不相交
if ( QdN < 0 ) {
return null;
}
// Ray intersects triangle.
// 射线与三角形相交.
return this.at( QdN / DdN, optionalTarget ); //返回交点.
};
}(),
/*
///applyMatrix4方法通过传递参数matrix4(旋转,缩放,移动等变换矩阵)对当前射线对象的原点及方向矢量,应用变换.
*/
///<summary>applyMatrix4</summary>
///<param name ="matrix4" type="Matrix4">(旋转,缩放,移动等变换矩阵</param>
///<returns type="Boolean">返回变换后的射线对象.</returns>
applyMatrix4: function ( matrix4 ) {
this.direction.add( this.origin ).applyMatrix4( matrix4 ); //对射线的方向矢量应用变换
this.origin.applyMatrix4( matrix4 ); //对射线的原点应用变换
this.direction.sub( this.origin );
this.direction.normalize();
return this; //返回变换后的射线对象
},
/*equals方法
///equals方法相当于比较运算符===,将当前射线和参数ray中的(origin,direction)值进行对比,返回bool型值.
*/
///<summary>equals</summary>
///<param name ="ray" type="Ray">射线(origin,direction)</param>
///<returns type="bool">返回true or false</returns>
equals: function ( ray ) {
return ray.origin.equals( this.origin ) && ray.direction.equals( this.direction ); //返回true or false
},
/*clone方法
///clone方法克隆一个射线对象.
*/
///<summary>clone</summary>
///<returns type="Ray">返回射线对象</returns>
clone: function () {
return new THREE.Ray().copy( this ); //返回射线对象
}
};
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Math/Ray.js文件的注释.
更多更新在 : https://github.com/omni360/three.js.sourcecode/blob/master/Three.js