Question

我目前有一个球从画布的墙壁上弹开。我在屏幕中间添加了一个矩形。每当球与矩形碰撞时，我希望它也能从它上面反弹，但我不知道该怎么做。我有一个名为“r”的矩形。

如何让球将矩形视为墙壁，并在它撞击时改变方向？代码示例将不胜感激。感谢。

这是我从球墙反弹的代码：

public void handle(ActionEvent t) {

                    // Moves the ball depending on the values of X and Y
                    circle.setLayoutX(circle.getLayoutX() + X);
                    circle.setLayoutY(circle.getLayoutY() + Y);                        

                    final Bounds bounds = canvas.getBoundsInLocal();
           // Boolean values to check if a wall has been hit
                    boolean leftWall = circle.getLayoutX() <= (bounds.getMinX() + circle.getRadius()); 
                    boolean topWall = circle.getLayoutY() <= (bounds.getMinY() + circle.getRadius());
                    boolean rightWall = circle.getLayoutX() >= (bounds.getMaxX() - circle.getRadius());
                    boolean bottomWall = circle.getLayoutY() >= (bounds.getMaxY() - circle.getRadius());



                    // If the bottom or top wall has been touched, the ball reverses direction.
                    if (bottomWall || topWall) {

                        Y = Y * -1;
                    }
                    // If the left or right wall has been touched, the ball reverses direction.
                    if (leftWall || rightWall) {
                        X = X * -1;
                    }
                }              

        }));

        loop.setCycleCount(Timeline.INDEFINITE);
        loop.play();
    }

Answer 1

我不知道JavaFx，但这是一个想法：

while (1) {
    bool btop = pos.y >= top
    bool bbottom = pos.y <= bottom
    bool bleft = pos.x <= left
    bool bright = pos.x >= right
    bool rect_btop = pos.y <= rect_top && pos.x >= rect_left && pos.x <= rect_right
    bool rect_bbottom = pos.y <= rect_bottom && pos.x >= rect_left && pos.x <= rect_right
    bool rect_bright = pos.x <= rect_right && pos.y >= rect_bottom && pos.y <= rect_top
    bool rect_bleft = pos.x >= rect_left && pos.y >= rect_bottom && pos.y <= rect_top

    if (btop || bottom || rect_btop || rect_bbottom)
        vy -= vy

    if (bleft || bright || rect_bleft || rect_bright)
        vx -= vx
}

然而，有更好和可扩展的解决方案（编码突破砖）。

Answer 2

this post对我有很大帮助

//example import for externally loaded library
//this will not form part of the bundle but will allow typescript to understand external libraries throughout the project
import _ from 'lodash'; 

declare global { 
    //Example global constant for libraries served via webpack externals. example webpack config:: externals: { _: 'lodash' }
    //This assumes lodash was already load in DOM for example in <head> via CDN link before main.js is loaded.
    const _: typeof _; 

    //example of custom types
    type JSONPrimitive = string | number | boolean | null;
    type JSONValue = JSONPrimitive | JSONObject | JSONArray;
    type JSONObject = { [member: string]: JSONValue };

    //example of custom interface
    interface JSONArray extends Array<JSONValue> {}
}

如何让球从Javafx中的物体上弹开？

2 个答案: