java - 光滑2d |以相同的速度射击

Question

问题:

我成功地在我的小游戏中实现了射击机制，但有一个问题。
如果我的光标离玩家较远，子弹的速度会更快；如果光标离玩家较近，子弹的速度会较慢。

所以我的问题是:如何让子弹始终以相同的速度移动？

链接:

The game (finished)

代码(来自 Shot.java):

public Shot(World world, Camera camera, float x, float y, int width, int height, Color color, float targetX, float targetY) {
    super(world, camera, x, y, width, height, color);

    this.targetX = targetX;
    this.targetY = targetY;

    dx = targetX - x;
    dy = targetY - y;
}

@Override
public void render(GameContainer gc, Graphics g) {
    g.setColor(color);
    g.fillOval(x - camera.getX(), y - camera.getY(), width, height);
}

@Override
public void update(GameContainer gc, int delta) {
    x += dx * delta * .005f;
    y += dy * delta * .005f;
}

我做到了!这是我的解决方案(感谢 Axis 的帮助):

float dx, dy;
Vector2f vector;

public Shot(World world, Camera camera, float x, float y, float targetX, float targetY, int width, int height, Color color) {
    super(world, camera, x, y, width, height, color);

    dx = targetX - x;
    dy = targetY - y;

    vector = new Vector2f(dx, dy).normalise();
}

@Override
public void render(GameContainer gc, Graphics g) {
    g.setColor(color);
    g.fillOval(x - camera.getX(), y - camera.getY(), width, height);
}

@Override
public void update(GameContainer gc, int delta) {
    x += vector.getX() * delta * 0.8f;
    y += vector.getY() * delta * 0.8f;
}

Answer 1

首先，我建议切换到 vector 类，而不是将所有内容拆分为 x 和 y。从长远来看，这将为您节省大量时间。

你需要做的就是改变

public Shot(World world, Camera camera, Vector2 pos, int width, int height, Color color, Vector2 target) {
    super(world, camera, pos, width, height, color);
    this.target = target

    //dx = targetX - x; get rid of this
    //dy = targetY - y; and this

//add a vector called direction

this.direction = (target - pos).Normalize();
}

@Override
public void update(GameContainer gc, int delta) {

pos += direction * delta * bulletSpeed;
}