尝试从Player类绘制时，Player不会移动

Question

因此，我目前正在为玩家重构游戏中的代码，并创建了一个玩家类：

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;

public class Player
{
    protected String name;
    protected float health, maxHealth;
    protected Texture texture;
    protected int xPos, yPos;

    public Player(String name, float maxHealth, Texture texture) {
        this(name, maxHealth, texture, 0, 0);
    }

    public Player(String name, float maxHealth, Texture texture, int xPos, int yPos) {
        this.name = name;
        this.health = this.maxHealth = maxHealth;
        this.texture = texture;
        this.xPos = xPos;
        this.yPos = yPos;
    }

    public Texture getTexture() {
        return this.texture;
    }

    public int getX() {
        return xPos;
    }
    public int getY() {
        return yPos;
    }

    public String getName() {
        return name;
    }

    public void draw(SpriteBatch spriteBatch) {
        spriteBatch.begin();
        spriteBatch.draw(texture, xPos, yPos, 0.5f, 0.5f, 0, 0,
                texture.getWidth(), texture.getHeight(), false, false);
        spriteBatch.end();
    }

    public void update(float delta) {
        processMovement(delta);
    }

    public void processMovement(float delta) {
        if(Gdx.input.isKeyPressed(Input.Keys.A)) {
            xPos -= 50 * delta;
        }
        if(Gdx.input.isKeyPressed(Input.Keys.D)) {
            xPos += 50 * delta;
        }
    }
}

我使用的是正交相机，我还没有添加任何地形，因为我下一步要做的是，但是我希望玩家始终留在中心，但当我绘制地形时，让玩家在地形周围移动。

我用来创建摄像头和绘制播放器的代码如下：

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Screen;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;

public class GameState implements Screen
{
    private PixelGame parent;

    private OrthographicCamera camera;
    private Player player;
    private Texture playerTexture;
    private SpriteBatch spriteBatch;

    public GameState(PixelGame parent) {
        this.parent = parent;
        this.playerTexture = new Texture(Gdx.files.internal("player/sprite.png"));
        this.player = new Player("Me", 20, playerTexture);
        this.spriteBatch = new SpriteBatch();
    }

    @Override
    public void render(float delta) {
        camera.update();
        spriteBatch.setProjectionMatrix(camera.combined);

        Gdx.gl.glClearColor(0, 0, 0.2f, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        player.draw(spriteBatch);
        player.update(delta);
    }

    @Override
    public void show() {
    }

    @Override
    public void dispose() {
    }

    @Override
    public void resize(int width, int height) {
        float ratio = (float)width / (float)height;
        camera = new OrthographicCamera(2f * ratio, 2f);
    }

    @Override
    public void pause() {
    }

    @Override
    public void resume() {
    }

    @Override
    public void hide() {
    }
}

player sprite似乎不会移动，但当我将值更改为>75时，player sprite会像无人事务一样在屏幕上冲刺。

Answer 1

你的类中的xPos和yPos是整型的。我会说这就是问题所在。您的processMovement()方法每秒被调用100次，而50 * delta很可能小于1，因此取整为0，因为必须将值存储在整型变量中。尝试将xPos和yPos更改为浮点数。

如果这不起作用(如果不尝试代码就不能确定)，那么就进行一些调试。设置断点。查看是否调用了processMovement()，如果是，那么变量delta的值是什么。如何计算。