java - 不断检查子弹是否触及节点

Question

我有一个非常简单的程序，您可以在其中使用W、A、S、D 和 space 键进行射击。所有的射击和移动动画都有效，但我不确定如何实现一个程序不断检查子弹是否触及节点(例如圆圈)的系统。

我在想我可以用一个ArrayList 来存储所有的子弹，然后使用一个TimerTask 来检查子弹是否碰到了一个节点；但我觉得这会减慢程序速度，而且子弹可能会在 TimerTask 等待再次运行时通过它们。

任何建议都会有所帮助。

代码:Pastebin

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Circle;
import javafx.animation.*;
import javafx.util.Duration;
public class functionalShooter extends Application {
    private String currentDirection = "W";
    public static void main(String[] args){ launch(args);   }
    @Override public void start(Stage stage) throws Exception{
        Pane root = new Pane();
        Scene scene = new Scene(root, 600, 400);
        stage.setScene(scene);
        stage.setResizable(false);
        stage.show();

        Circle player = new Circle(10);
        player.setLayoutX(300);
        player.setLayoutY(200);

        Circle other = new Circle(100, 100, 10);

        root.getChildren().addAll(player, other);

        //key events
        scene.setOnKeyPressed(event -> {
            switch(event.getCode()){
                case A:
                    player.setLayoutX(player.getLayoutX()-10);
                    currentDirection = "A";
                    break;
                case D:
                    player.setLayoutX(player.getLayoutX()+10);
                    currentDirection = "D";
                    break;
                case W:
                    player.setLayoutY(player.getLayoutY()-10);
                    currentDirection = "W";
                    break;
                case S:
                    player.setLayoutY(player.getLayoutY()+10);
                    currentDirection = "S";
                    break;
                case SPACE:
                    if (currentDirection.equals("D")){
                        Circle newCircle = new Circle(player.getLayoutX()+10, player.getLayoutY(), 5);
                        root.getChildren().add(newCircle);
                        shoot(newCircle);
                    }
                    else if (currentDirection.equals("A")){
                        Circle newCircle = new Circle(player.getLayoutX()-10, player.getLayoutY(), 5);
                        root.getChildren().add(newCircle);
                        shoot(newCircle);
                    }
                    else if (currentDirection.equals("S")){
                        Circle newCircle = new Circle(player.getLayoutX(), player.getLayoutY()+10, 5);
                        root.getChildren().add(newCircle);
                        shoot(newCircle);
                    }
                    else {
                        Circle newCircle = new Circle(player.getLayoutX(), player.getLayoutY()-10, 5);
                        root.getChildren().add(newCircle);
                        shoot(newCircle);
                    }
                    break;
            }
        });
    }

    private void shoot(Circle bullet){
        Timeline timeline = new Timeline();
        if (currentDirection.equals("D")){
            KeyValue start = new KeyValue(bullet.translateXProperty(), 0);
            KeyValue end = new KeyValue(bullet.translateXProperty(), 800);
            KeyFrame startF = new KeyFrame(Duration.ZERO, start);
            KeyFrame endF = new KeyFrame(Duration.seconds(10), end);
            timeline.getKeyFrames().addAll(startF, endF);
        }
        else if (currentDirection.equals("A")){
            KeyValue start = new KeyValue(bullet.translateXProperty(), 0);
            KeyValue end = new KeyValue(bullet.translateXProperty(), -800);
            KeyFrame startF = new KeyFrame(Duration.ZERO, start);
            KeyFrame endF = new KeyFrame(Duration.seconds(10), end);
            timeline.getKeyFrames().addAll(startF, endF);
        }
        else if (currentDirection.equals("S")){
            KeyValue start = new KeyValue(bullet.translateYProperty(), 0);
            KeyValue end = new KeyValue(bullet.translateYProperty(), 800);
            KeyFrame startF = new KeyFrame(Duration.ZERO, start);
            KeyFrame endF = new KeyFrame(Duration.seconds(10), end);
            timeline.getKeyFrames().addAll(startF, endF);
        }
        else{
            KeyValue start = new KeyValue(bullet.translateYProperty(), 0);
            KeyValue end = new KeyValue(bullet.translateYProperty(), -800);
            KeyFrame startF = new KeyFrame(Duration.ZERO, start);
            KeyFrame endF = new KeyFrame(Duration.seconds(10), end);
            timeline.getKeyFrames().addAll(startF, endF);
        }
        timeline.setAutoReverse(false);
        timeline.setCycleCount(1);
        timeline.play();
    }
}

Answer 1

您可以使用 Shape.intersect() 检查 bullet 是否与 other 相交在自定义中 Interpolator提供给每个相关的KeyValue .下面的片段向 shoot() 添加了一个 Interpolator，但是每个方向都需要一个相同的插值器。实现是线性的，简单地返回 t 不变，但你也可以看看 this抛物线插值器。我还使 other 成为一个类变量，shoot() 可以访问它。我毫不迟疑地向空中发射了一打子弹。请注意，您不需要 start 值:“一个将是 synthesized，使用当前的目标值”播放动画。

private Circle other = new Circle(100, 100, 10);
…
else {
    KeyValue end = new KeyValue(bullet.translateYProperty(), -800, new Interpolator() {
        @Override
        protected double curve(double t) {
            if (!Shape.intersect(bullet, other).getBoundsInLocal().isEmpty()) {
                System.out.println("Intersection");
            }
            return t;
        }
    });
    KeyFrame endF = new KeyFrame(Duration.seconds(10), end);
    timeline.getKeyFrames().addAll(endF);
}