How to orient the muzzle of a gun ? [JavaFX]

问题

I am creating a game in which you use guns and play against the computer/someone else. You can orient that gun with a slider. But I don't manage to orient the muzzle of the gun. I tried in different ways, nothing worked as expected. I googled a bit but I found nothing that worked and nothing that seems to have a chance of working. So I ask you, what haven't I tried yet ? What should I do different ?

Here is a picture explaining what I said :

Expectations

Here is the concerned code :

package canons;

import javafx.scene.Parent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;

public class Canon extends Parent {
    private int posX = 500; // x position of the gun
    private int posY = 250; // y position of the gun
    private int tailleCorps = 20; // size of the body
    private Rectangle buse; // muzzle
    private Circle corps; // body

    public Canon(Color couleurCorps, Color couleurBuse) {
        this.getChildren().addAll(getBuse(), getCorps());
        this.setTranslateX(posX);
        this.setTranslateY(posY);
    }

    public Rectangle getBuse() {
        if(buse == null) { // verify if they aren't created yet. Security.
            buse = new Rectangle();
            buse.setWidth(70);
            buse.setHeight(20);
            buse.setArcWidth(15); // round extremities
            buse.setArcHeight(30);
            buse.setFill(Color.BLACK);
            buse.setTranslateX(posX);
            buse.setTranslateY(posY + tailleCorps/4);
        }    
        return buse;
    }

    public Circle getCorps() {
        if(corps == null) { // verify if they aren't created yet. Security.
            corps = new Circle(tailleCorps);
            corps.setTranslateX(posX);
            corps.setTranslateY(posY);
        }
        return corps;
    }
}

If I haven't been clear enough, please feel free to ask me any other questions on my problem/code. Thanks.

EDIT:

Using buse.getTransforms.add(new Rotate(angle, x, y));

EDIT 2:

I still didn't find the way to make it work... I've post an answer where I show what I've now. Thanks.

回答1:

I've found another solution, and it is for the moment the best I've found. It's not what I want but it is whats look like it the most.

So this is the code now :

package canons;

import javafx.scene.Parent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.scene.transform.Rotate;

public class Canon extends Parent {
    private int posX = 500, posY = 250;
    private double valeurAngle;
    private Rectangle buse;
    private Circle corps, obus;

    public Canon(Color couleurCorps, Color couleurBuse) {
        this.getChildren().addAll(getBuse(), getCorps());
        this.setTranslateX(posX);
        this.setTranslateY(posY);
    }

    public Rectangle getBuse() {
        if(buse == null) { // sécurité, évite de recréer plusieurs fois le même objet
            buse = new Rectangle();
            buse.setWidth(60);
            buse.setHeight(20);
            buse.setArcWidth(15); // extrémités arrondies
            buse.setArcHeight(30);
            buse.setFill(Color.BLACK);
            buse.setTranslateX(posX);
            buse.setTranslateY(posY - buse.getHeight() / 2);
        }
        return buse;
    }

    public Circle getCorps() {
        if(corps == null) { // sécurité, évite de recréer plusieurs fois le même 
            corps = new Circle(20);
            corps.setTranslateX(posX);
            corps.setTranslateY(posY);
        }
        return corps;
    }

    public void orienter(double angle) {
        Rotate rotate = new Rotate();
        rotate.setPivotX(buse.getX()); //Pivot X Top-Left corner
        rotate.setPivotY(buse.getY()); //Pivot Y
        rotate.setAngle(angle); //Angle degrees
        buse.getTransforms().add(rotate);
        valeurAngle = angle;
    }

And this is what I have :

First exemple

Second exemple

Third exemple

Fourth exemple

Another one

Last one

I hope you now have a better idea of what I mean. Thanks.

来源：https://stackoverflow.com/questions/53178512/how-to-orient-the-muzzle-of-a-gun-javafx