Question

我试图检测JavaFX中两个形状之间的碰撞，这个方法不起作用。我正在检索两个形状的节点，然后使用intersects方法来比较它们的位置。我可以在这里改变什么？谢谢！

public void collisionDetection() {
        if (_circle.getNode().intersects(_square.getRect().getX(), _square.getRect().getY(), 100.0, 30.0)) {
        System.out.println("collision detected");
        }
    }
}

Answer 1

评论中引用的其他问题（How to use intersect() method of Node Class in JavaFX?）的答案是不准确的。 Node＃intersects（Bounds）方法不将另一个节点的局部边界作为输入，而是将另一个节点的边界作为调用节点的局部坐标系。因此，您需要转换边界以便能够检测冲突，如下所示：

if (_circle.intersects(
        _circle.sceneToLocal(_square.localToScene(
            _square.getBoundsInLocal()))) {
    // ...
}

Answer 2

我创建了一个碰撞检测应用程序，您可以使用它来更好地理解碰撞检测。

主要：

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

/**
 *
 * @author blj0011
 */
public class CollisionDection extends Application {

    @Override
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));

        Scene scene = new Scene(root);

        stage.setScene(scene);
        stage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

FXML：

<?xml version="1.0" encoding="UTF-8"?>

<?import java.lang.Double?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.shape.Polygon?>

<AnchorPane id="AnchorPane" fx:id="apMain" prefHeight="446.0" prefWidth="577.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8.0.111" fx:controller="collisiondection.FXMLDocumentController">
    <children>
        <Label fx:id="lblMain" layoutX="254.0" layoutY="408.0" minHeight="16" minWidth="69" />
      <Polygon fx:id="polyOne" fill="DODGERBLUE" layoutX="122.0" layoutY="166.0" stroke="BLACK" strokeType="INSIDE">
        <points>
          <Double fx:value="-50.0" />
          <Double fx:value="40.0" />
          <Double fx:value="50.0" />
          <Double fx:value="40.0" />
          <Double fx:value="0.0" />
          <Double fx:value="-60.0" />
        </points>
      </Polygon>
      <Polygon fx:id="polyTwo" fill="DODGERBLUE" layoutX="419.0" layoutY="166.0" stroke="BLACK" strokeType="INSIDE">
        <points>
          <Double fx:value="-50.0" />
          <Double fx:value="40.0" />
          <Double fx:value="50.0" />
          <Double fx:value="40.0" />
          <Double fx:value="0.0" />
          <Double fx:value="-60.0" />
        </points>
      </Polygon>
    </children>
</AnchorPane>

控制器：

import java.net.URL;
import java.util.ResourceBundle;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.geometry.Point2D;
import javafx.scene.control.Label;
import javafx.scene.input.MouseEvent;
import javafx.scene.shape.Polygon;
import javafx.scene.shape.Shape;

/**
 *
 * @author sedj601
 */
public class FXMLDocumentController implements Initializable {

    @FXML private Label lblMain;
    @FXML private Polygon polyOne, polyTwo;    

    final ObjectProperty<Point2D> mousePosition = new SimpleObjectProperty<>();

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
        polyOne.setOnMousePressed((MouseEvent event) -> {
            mousePosition.set(new Point2D(event.getSceneX(), event.getSceneY()));
        });

        polyOne.setOnMouseDragged((MouseEvent event) -> {
            double deltaX = event.getSceneX() - mousePosition.get().getX();
            double deltaY = event.getSceneY() - mousePosition.get().getY();
            polyOne.setLayoutX(polyOne.getLayoutX()+deltaX);
            polyOne.setLayoutY(polyOne.getLayoutY()+deltaY);
            mousePosition.set(new Point2D(event.getSceneX(), event.getSceneY()));

            Shape intersect = Shape.intersect(polyOne, polyTwo);

            if(intersect.getBoundsInLocal().getWidth() != -1)
            {
                System.out.println("This object can overlap other the other object!");
                lblMain.setText("Collision detected!");
            }
            else
            {
                intersect.getBoundsInLocal().getWidth();
                lblMain.setText("Collision not detected!");
            }            
        });

        polyTwo.setOnMousePressed((MouseEvent event) -> {
            mousePosition.set(new Point2D(event.getSceneX(), event.getSceneY()));
        });

        polyTwo.setOnMouseDragged((MouseEvent event) -> {
            double deltaX = event.getSceneX() - mousePosition.get().getX();
            double deltaY = event.getSceneY() - mousePosition.get().getY();
            polyTwo.setLayoutX(polyTwo.getLayoutX() + deltaX);
            polyTwo.setLayoutY(polyTwo.getLayoutY() + deltaY);
            mousePosition.set(new Point2D(event.getSceneX(), event.getSceneY()));

            Shape intersect = Shape.intersect(polyOne, polyTwo);
            {
                if(intersect.getBoundsInLocal().getWidth() != -1)
                {      
                    System.out.println("This object can not overlap other the other object!");
                    polyTwo.setLayoutX(polyTwo.getLayoutX() - deltaX);
                    polyTwo.setLayoutY(polyTwo.getLayoutY() - deltaY);
                    lblMain.setText("Collision detected!");
                }
                else
                {
                    lblMain.setText("Collision not detected!");
                }
            }
        });   
    }
}

JavaFX两个形状相交 - 碰撞方法不起作用

2 个答案: