代碼來計算角度不起作用

Question

我想要計算兩個點之間在java中的角度度數。這是我用來計算角度的代碼。

public static double calcAngle(Point.Double p1, Point.Double p2) 
{ 
    double xDiff = p2.x - p1.x; 
    double yDiff = p2.y - p1.y; 
    return Math.toDegrees(Math.atan2(yDiff, xDiff)); 
} 

這裏是我的代碼

double playerX = panel.getCharacter().getX(); 
double playerY = panel.getCharacter().getY(); 
int dispenserX = x*Block.WIDTH; 
int dispenserY = y*Block.HEIGHT; 
Point2D.Double player = new Point2D.Double(playerX, playerY); 
Point2D.Double dispenser = new Point2D.Double(dispenserX, dispenserY); 
double angle = calcAngle(dispenser, player); 
System.out.println(angle); 
panel.addEntity(newEntityFireball(x*Block.WIDTH,y*Block.HEIGHT,angle,1));//adds a fireball at a 45 degree angle 
System.out.println(angle); 
System.out.println(dispenser); 
System.out.println(player); 

從分配器發射火球，其餘不是針對球員，爲什麼？它似乎以一個隨機的角度移動。這裏

編輯是火球類

import java.awt.image.BufferedImage; 
import java.io.IOException; 

import javax.imageio.ImageIO; 

public class EntityFireball extends Entity 
{ 
    private double angle; 
    private double speed; 
    private int life; 

    public EntityFireball(double x, double y, double angle, double speed) 
    { 
     super(x, y, 20, 20); 
     this.angle = angle; 
     this.speed = speed; 
    } 

    public void update(boolean inRange) 
    { 
     life++; 

     if(life>2500) 
      removeEntityFromGame(this); 

     if(inRange) 
     { 
      float xDirection = (float) (Math.sin((float) Math.toRadians(angle)) * speed); 
      float yDirection = (float) (Math.cos((float) Math.toRadians(angle)) * -speed); 
      double newX = getX() + xDirection; 
      double newY = getY() + yDirection; 
      setX(newX); 
      setY(newY); 
     } 
    } 

    public BufferedImage getImage() 
    { 
     try 
     { 
      return ImageIO.read(Main.class.getResourceAsStream("/images/Fireball.png")); 
     } 
     catch (IOException e) 
     { 
      return null; 
     } 
    } 
    } 

Answer 1

變化

float xDirection = (float) (Math.sin((float) Math.toRadians(angle)) * speed); 
float yDirection = (float) (Math.cos((float) Math.toRadians(angle)) * -speed); 

到

float xDirection = (float) (Math.cos((float) Math.toRadians(angle)) * speed); 
float yDirection = (float) (Math.sin((float) Math.toRadians(angle)) * speed); 

此外，要更改2D路線矢量成一個角度，然後改變其回2D課程矢量。這是一個相當數量的循環觸發，使您得到與您最初一樣的答案。有沒有一個原因，你不只是離開它的載體？

public static Point2D.Double calcAngle(Point.Double p1, Point.Double p2){ 
    double xDiff = p2.x - p1.x; 
    double yDiff = p2.y - p1.y; 
    return new Point2D.Double(xDiff,yDiff); 
} 


public class EntityFireball extends Entity { 
    private Point2D.Double course; 
    private double speed; 
    private int life; 

    public EntityFireball(double x, double y, double angle, Point2D.Double course){ 
     super(x, y, 20, 20); 
     this.angle = angle; 
     this.course=course; 
    } 

    public void update(boolean inRange){ 
     life++; 
     if(life>2500) 
      removeEntityFromGame(this); 

     if(inRange){ 
      float xDirection = course.x; 
      float yDirection = course.y; 
      double newX = getX() + xDirection; 
      double newY = getY() + yDirection; 
      setX(newX); 
      setY(newY); 
     } 
    } 
} 

Answer 2

只取絕對值：

public static double calcAngle(Point.Double p1, Point.Double p2) 
{ 
    double xDiff = Math.abs(p2.x - p1.x); 
    double yDiff = Math.abs(p2.y - p1.y); 
    return Math.toDegrees(Math.atan2(yDiff, xDiff)); 
} 

Answer 3

我的猜測是，你已經轉換角度度，但後來都將它視爲弧度當你進行繪圖時的角度。這可以解釋爲什麼它在「隨機方向」