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java - JavaFX 使 imageView 朝着它所面对的方向前进

问题描述

我想让一个 imageView 对象移动到它所面对的方向。

我让它在 X/Y 轴上移动并让它旋转，但我真的不知道如何解决这个移动到它所面临的方向的问题（例如，在我的代码中我使用汽车，我只想让它朝其面对的方向移动）

我很感激任何我可以学习的想法或教程。

public class Main extends Application {

    private static final double W = 800;
    private static final double H = 600;
    private boolean goNorth, goSouth, goWest, goEast;
    private ImageView hero;
    private int toAngle = 0;


    @Override
    public void start(Stage primaryStage) throws FileNotFoundException {
        FileInputStream hero_image_input = new FileInputStream("C:\\Users\\A650262\\Desktop\\police-310208_1280.png");
        Image hero_image = new Image(hero_image_input);
        hero = new ImageView(hero_image);

        hero.setFitHeight(120);
        hero.setFitWidth(200);

        BorderPane root = new BorderPane();
        Scene scene = new Scene(root,800,800);

        scene.setOnKeyPressed(new EventHandler<KeyEvent>(){ 
            @Override
            public void handle(KeyEvent event)
            {
                switch(event.getCode())
                {
                case UP: goNorth = true; break;
                case DOWN: goSouth = true; break;
                case LEFT: goWest = true; break;
                case RIGHT: goEast = true; break;
                }
            }
        });

        scene.setOnKeyReleased(new EventHandler<KeyEvent>() {
            @Override
            public void handle(KeyEvent event)
            {
                switch(event.getCode())
                {
                case UP: goNorth = false; break;
                case DOWN: goSouth = false; break;
                case LEFT: goWest = false; break;
                case RIGHT: goEast = false; break;
                }
            }
        });


        root.getChildren().addAll(hero);
        primaryStage.setScene(scene);
        primaryStage.show();

        AnimationTimer timer = new AnimationTimer() {
            @Override
            public void handle(long now) {
                int dx = 0, dy = 0;

                if (goNorth) dy -= 5;
                if (goSouth) dy += 5;
                if (goEast) rotate(3);
                if (goWest)  rotate(-3);

                moveHeroBy(dx, dy);
            }
        };
        timer.start();
    }

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

    private void moveHeroBy(int dx, int dy) {
        if (dx == 0 && dy == 0) return;
        double x = dx + hero.getLayoutX();
        double y = dy + hero.getLayoutY();
        moveHeroTo(x,y);

    }

    private void moveHeroTo(double x, double y) {
        hero.relocate(x, y);
        System.out.println(hero.getNodeOrientation() + " " + hero.getEffectiveNodeOrientation());

    }

    public void rotate(int angle){

        toAngle = toAngle + angle;
        if (toAngle == 360)
        {
            toAngle = 0;
        }
        hero.setRotate(toAngle);
    }


}

标签： javajavafximageview

解决方案

使用Rotate和Translate变换来移动图像。这样，您可以使用 将Rotate汽车最初面向的方向转换为当前方向。

private final Rotate rotate = new Rotate();
private final Translate translate = new Translate();

// upwards facing direction TODO: adjust
private final Point2D initialDirection = new Point2D(0, -1);

rotate.setPivotX(hero.getFitWidth() / 2);
rotate.setPivotY(hero.getFitHeight() / 2);
hero.getTransforms().addAll(translate, rotate);

AnimationTimer timer = new AnimationTimer() {
    @Override
    public void handle(long now) {
        double delta = 0;

        if (goNorth) {
            delta += 5;
        }
        if (goSouth) {
            delta -= 5;
        }
        if (goEast) {
            rotate(3);
        }
        if (goWest) {
            rotate(-3);
        }

        Point2D pt = rotate.deltaTransform(initialDirection.multiply(delta));

        moveHeroBy(pt.getX(), pt.getY());
    }
};

private void moveHeroBy(double dx, double dy) {
    if (dx == 0 && dy == 0) {
        return;
    }
    double x = dx + translate.getX();
    double y = dy + translate.getY();
    translate.setX(x);
    translate.setY(y);
}

public void rotate(int angle) {
    angle += rotate.getAngle();
    if (angle == 360) {
        angle = 0;
    }
    rotate.setAngle(angle);
}

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