Libgdx之Sprite 精灵类

已经介绍了这么多容器类来加载图片，下面出场的的是Sprite，也就是精灵类，这个可以说是集大成者，里面封装了更多的方法来操作纹理。
Sprite可以保存几何属性，大小(size, width, height)，位置(position) 和旋转中心点(origin).
精灵总是一个矩形，而且绘制起点也是左下角

下面说说在实际中经常使用到的几个方法

    /** Sets the position where the sprite will be drawn. If origin, rotation, or scale are changed, it is slightly more efficient * to set the position after those operations. If both position and size are to be changed, it is better to use * {@link #setBounds(float, float, float, float)}. */
    public void setPosition (float x, float y)

/** Sets the position relative to the current position where the sprite will be drawn. If origin, rotation, or scale are * changed, it is slightly more efficient to translate after those operations. */
    public void translate (float xAmount, float yAmount) 

/** Place origin in the center of the sprite */
    public void setOriginCenter()

// 下面这个方法经常来用作碰撞检测
/** Returns the bounding axis aligned {@link Rectangle} that bounds this sprite. The rectangles x and y coordinates describe its * bottom left corner. If you change the position or size of the sprite, you have to fetch the triangle again for it to be * recomputed. * * @return the bounding Rectangle */
    public Rectangle getBoundingRectangle () 

测试代码

Sprite sprite, sprite2;
    SpriteBatch batch;
    float rotation = 2;
    Rectangle rec, rec2;

    @Override
    public void create() {
        sprite = new Sprite(new Texture(Gdx.files.internal("badlogic.jpg")));
        sprite2 = new Sprite(new Texture(Gdx.files.internal("badlogic.jpg")));
        // 设置(320, 240)为sprite的中心点，并且以它为中心绘制
        sprite.setCenter(320, 240);
        sprite.setOriginCenter(); // 设置旋转中心在中心
        rec = sprite.getBoundingRectangle(); // 后面做碰撞检测用

        sprite2.setSize(60, 60); // 设置精灵大小为40*40
        batch = new SpriteBatch();
    }

    @Override
    public void render() {
        Gdx.gl.glClearColor(1, 0, 0, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        float dt = Gdx.graphics.getDeltaTime();
        rotation += dt / 360;
        sprite.rotate(rotation);

        // 每秒钟移动20
        sprite2.translate(20 * dt, 20 * dt);

        rec2 = sprite2.getBoundingRectangle();
        if (rec2.overlaps(rec)) {
            System.out.println("conflict");
            sprite.setAlpha(0.5f);
            sprite2.setAlpha(1.0f);
            sprite2.setScale(2.0f);
        }

        batch.begin();
        sprite.draw(batch);
        sprite2.draw(batch, 0.8f);
        batch.end();
    }

    @Override
    public void dispose() {
        sprite.getTexture().dispose();
        sprite2.getTexture().dispose();
        batch.dispose();
    }