正如标题中所提到的,我有两个Circle
' s第一个是可拖动的,第二个是固定的,我会旋转(带阻力)第一个围绕第二个而不重叠,但我的Circle
反应奇怪,我确定错误来自阻力条件,但我不知道如何解决它,那个& #39;为什么我需要你的帮助,这是一个极小且可测试的代码:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
public class Collision extends Application{
private Pane root = new Pane();
private Scene scene;
private Circle CA = new Circle(20);
private Circle CB = new Circle(20);
private double xOffset = 0;
private double yOffset = 0;
@Override
public void start(Stage stage) throws Exception{
initCircles();
scene = new Scene(root,500,500);
stage.setScene(scene);
stage.show();
}
private void initCircles(){
CA.setCenterX(100);
CA.setCenterY(100);
CA.setFill(Color.rgb(255, 0, 0,0.2));
CA.setStroke(Color.BLACK);
CB.setCenterX(250);
CB.setCenterY(200);
CB.setFill(Color.rgb(255, 0, 0,0.2));
CB.setStroke(Color.BLACK);
CA.setOnMousePressed(evt->{
xOffset = CA.getCenterX() - evt.getSceneX();
yOffset = CA.getCenterY() - evt.getSceneY();
});
CA.setOnMouseDragged(evt->{
//get Scene coordinate from MouseEvent
drag(evt.getSceneX(),evt.getSceneY());
});
root.getChildren().addAll(CA,CB);
}
private void drag(double x, double y){
/* calculate the distance between
* the center of the first and the second circle
*/
double distance = Math.sqrt (Math.pow(CA.getCenterX() - CB.getCenterX(),2) + Math.pow(CA.getCenterY() - CB.getCenterY(),2));
if (!(distance < (CA.getRadius() + CB.getRadius()))){
CA.setCenterX(x + xOffset);
CA.setCenterY(y + yOffset);
}else{
/**************THE PROBLEM :Condition to drag************/
CA.setCenterX(CA.getCenterX() - (CB.getCenterX()-CA.getCenterX()));
CA.setCenterY(CA.getCenterY() - (CB.getCenterY()-CA.getCenterY()));
/*What condition must be established for the
* circle to behave correctly
*/
/********************************************************/
}
}
public static void main(String[] args) {
launch(args);
}
}
以下是简要概述:
注意: 为了我的辩护,我搜索并发现了几个与我相近但没有精确或精确解决方案的主题,其中包括:
-The circle remains blocked at the time of the collision
-Two circle that push each other
-JavaScript, Difficult to understand and convert to java
感谢您的帮助!
答案 0 :(得分:2)
Point2D
可以解释为2D矢量,并且具有从中创建新矢量等的有用方法。您可以这样做:
private void drag(double x, double y){
// place drag wants to move circle to:
Point2D newCenter = new Point2D(x + xOffset, y+yOffset);
// center of fixed circle:
Point2D fixedCenter = new Point2D(CB.getCenterX(), CB.getCenterY());
// minimum distance between circles:
double minDistance = CA.getRadius() + CB.getRadius() ;
// if they overlap, adjust newCenter:
if (newCenter.distance(fixedCenter) < minDistance) {
// vector between fixedCenter and newCenter:
Point2D newDelta = newCenter.subtract(fixedCenter);
// adjust so that length of delta is distance between two centers:
Point2D adjustedDelta = newDelta.normalize().multiply(minDistance);
// move newCenter to match adjusted delta:
newCenter = fixedCenter.add(adjustedDelta);
}
CA.setCenterX(newCenter.getX());
CA.setCenterY(newCenter.getY());
}
显然,你可以在不使用Point2D
而只是进行计算的情况下完成所有这些工作,但我认为API调用使代码更容易理解。