在TimeLine中进行Javafx碰撞检测

Question

我使用时间线动画线，但我不能检测碰撞。这是一个简短的例子，我基本上是在尝试做什么。

    Line line = new Line(100, 200, 200, 200);
    Line line1= new Line(350,50,350,300);

    Timeline animation = new Timeline(
            new KeyFrame(Duration.seconds(1.5), new KeyValue(line.endXProperty(), 400))
    );
    animation.setCycleCount(1);
    animation.play();

    if(line.getBoundsInParent().intersects(line1.getBoundsInParent())){
        System.out.println("Collision!");
    }

    Pane root = new Pane(line);
    root.getChildren().add(line1);
    Scene scene = new Scene(root, 400, 400);
    primaryStage.setScene(scene);
    primaryStage.show();

我使用了我在堆栈溢出中找到的其他一些代码，方法，想法。就像下面这样：

    Bounds bounds = line.getLayoutBounds();
    Shape intersect = Shape.intersect(line, line1);

    boolean intersects = intersect.getBoundsInLocal().getWidth() != -1;

    System.out.println("Intersects: " + intersects);

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

以及此代码的一些变体。

任何想法都会有所帮助

Answer 1

在这种情况下，当< code>line.endX达到350时，就会发生“冲突”(线条第一次相交)。

因此，您可以简单地执行以下操作：

    BooleanBinding intersecting = line.endXProperty().greaterThanOrEqualTo(350);
    intersecting.addListener((obs, wasIntersecting, isNowIntersecting) -> {
        System.out.println("Collision!");
    });

即:

import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.binding.BooleanBinding;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
import javafx.util.Duration;

public class AnimatedLine extends Application {

    @Override
    public void start(Stage primaryStage) {
        Line line = new Line(100, 200, 200, 200);
        Line line1= new Line(350,50,350,300);

        BooleanBinding intersecting = line.endXProperty().greaterThanOrEqualTo(350);
        intersecting.addListener((obs, wasIntersecting, isNowIntersecting) -> {
            System.out.println("Collision!");
        });

        Timeline animation = new Timeline(
                new KeyFrame(Duration.seconds(1.5), new KeyValue(line.endXProperty(), 400))
        );
        animation.setCycleCount(1);
        animation.play();


        Pane root = new Pane(line);
        root.getChildren().add(line1);
        Scene scene = new Scene(root, 400, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

一般来说，检测两个线段是否相交可能比一个水平一个垂直的情况要困难一点，但是你总是可以很容易地求解方程并做类似的事情。