JavaFX 类 Point3D用法及代码示例

Point3D类是JavaFX的一部分。此类定义3D空间中的3维点。 Point3D类通过其x，y，z坐标表示3D点。

该类的构造函数是：

• Point3D(double x, double y, double z)：使用指定的坐标创建Point3D对象。

常用方法：

方法	说明
distance(double x, double y, double z)	计算此点与指定点之间的距离
distance(Point3D p)	计算此点与指定Point3D对象之间的距离
equals(java.lang.Object o)	返回该点的哈希码值。
getX()	返回x坐标
getY()	返回y坐标
getZ()	返回z坐标
hashCode()	返回此Point3D对象的哈希码。

下面的程序将说明Point3D类的用法：

1. Java程序创建一个Point3D对象并显示其坐标并找到其与原点的距离：在此程序中，我们通过传递其x，y，z坐标作为参数来创建一个名为point3d_1的Point3D对象。我们使用getX()，getY()，getZ()函数获取x，y，z参数并显示它。我们还计算点到原点的距离并显示出来。

   // Java program to create a point 3D  
   // object and display its coordinates 
   // and find its distance from origin 
   import javafx.geometry.Point3D; 
     
   public class Point3D_1 { 
     
       // Main Method 
       public static void main(String args[]) 
       { 
     
           // Create a point3D object 
           Point3D point3d_1 = new Point3D(20.0f, 50.0f, 70.0f); 
     
           double x, y, z; 
     
           // get the coordinates of the point 
           x = point3d_1.getX(); 
           y = point3d_1.getY(); 
           z = point3d_1.getZ(); 
     
           // display the coordinates of the point 
           System.out.println("x coordinate = " + x  
                               + ", y coordinate = " 
                               + y + ", z coordinate = " + z); 
     
           // print its distance from origin 
           System.out.println("Distance From Origin = " 
                        + point3d_1.distance(0, 0, 0)); 
       } 
   }

   输出：

   x coordinate = 20.0, y coordinate = 50.0, z coordinate = 70.0
   Distance From Origin = 88.31760866327846
   

2. Java程序创建3个Point3D对象并显示其坐标和距原点的距离，并检查3个点中的哪个点相似以及两个点之间的距离：在此程序中，我们通过传递其x，y，z坐标作为参数来创建3个Point3D对象，分别命名为point3d_1，point3d_2，point3d_3。我们使用getX()，getY()，getZ()函数获取x，y，z参数并显示它。我们还计算了该点到原点的距离，并针对三个点中的每一个都显示了该距离。我们还使用equals()函数显示两个点是否相等，并使用距离函数显示两个点之间的距离。

   // Java program to create 3 Point3D objects and  
   // display their coordinates and distance from  
   // origin and check which of the 3 points are  
   // similar and their distances between two points 
   import javafx.geometry.Point3D; 
     
   public class Point3D_2 { 
     
       // Main Method 
       public static void main(String args[]) 
       { 
     
           // create three point3D objects 
           Point3D point3d_1 = new Point3D(20.0f, 50.0f, 70.0f); 
           Point3D point3d_2 = new Point3D(20.0f, 50.0f, 70.0f); 
           Point3D point3d_3 = new Point3D(200.0f, 20.0f, 90.0f); 
     
           // display the coordinates of the 3 points 
           display(point3d_1); 
           display(point3d_2); 
           display(point3d_3); 
     
           // check whether any point is equal to other or not 
           System.out.println("Point 1 equals point 2 = " 
                          + point3d_1.equals(point3d_2)); 
     
           System.out.println("Point 2 equals point 3 = " 
                          + point3d_2.equals(point3d_3)); 
     
           System.out.println("Point 3 equals point 1 = " 
                           + point3d_3.equals(point3d_1)); 
     
           // distance between two points 
           System.out.println("Distane between point 1 and point 2 = " 
                                     + point3d_1.distance(point3d_2)); 
     
           System.out.println("Distane between point 2 and point 3 = " 
                                      + point3d_2.distance(point3d_3)); 
     
           System.out.println("Distane between point 3 and point 1 = " 
                                     + point3d_3.distance(point3d_1)); 
       } 
     
       // Display Method 
       public static void display(Point3D point3d) 
       { 
     
           double x, y, z; 
     
           // get the coordinates of the point 
           x = point3d.getX(); 
           y = point3d.getY(); 
           z = point3d.getZ(); 
     
           // display the coordinates of the point 
           System.out.println("x coordinate = " + x  
                              + ", y coordinate = " 
                              + y + ", z coordinate = " + z); 
     
           // print its distance from origin 
           System.out.println("Distance From Origin = " +  
                               point3d.distance(0, 0, 0)); 
       } 
   }

   输出：

   x coordinate = 20.0, y coordinate = 50.0, z coordinate = 70.0
   Distance From Origin = 88.31760866327846
   x coordinate = 20.0, y coordinate = 50.0, z coordinate = 70.0
   Distance From Origin = 88.31760866327846
   x coordinate = 200.0, y coordinate = 20.0, z coordinate = 90.0
   Distance From Origin = 220.22715545545242
   Point 1 equals point 2 = true
   Point 2 equals point 3 = false
   Point 3 equals point 1 = false
   Distane between point 1 and point 2 = 0.0
   Distane between point 2 and point 3 = 183.5755975068582
   Distane between point 3 and point 1 = 183.5755975068582
   

注意：以上程序可能无法在在线IDE中运行。请使用离线编译器。

参考：https://docs.oracle.com/javafx/2/api/javafx/geometry/Point3D.html