Libgdx之TexturePacker TextureAtlas

Libgdx发展之初默认使用OpenGL ES 1.0，这是要求图片大小必须是2的n次方。但现在默认是使用的是2.0，这样就不必要求图片的大小。但是为了节约内存，还是推荐使用图片打包工具，将图片打包，这时使用的工具就是TexturePacker。
文章用到的工具下载： http://download.csdn.net/detail/zqiang_55/9480077

Texturepacker

下面的截图列出了对工具的一些说明

TextureAtlas

说白了TextureAtlas就是一个解析TexturePacker打包的图片一个工具。下面先看一下其类图

从类图可以知道，TextureAtlas继承了Disposable接口，因此在程序退出时需要调用dispose()方法。AtlasRegion是一个内部类，继承自TextureRegion

/** Loads the specified pack file using {@link FileType#Internal}, using the parent directory of the pack file to find the page * images. */
    public TextureAtlas (String internalPackFile) {
        this(Gdx.files.internal(internalPackFile));
    }

    /** Loads the specified pack file, using the parent directory of the pack file to find the page images. */
    public TextureAtlas (FileHandle packFile) {
        this(packFile, packFile.parent());
    }

    /** Returns the first region found with the specified name. This method uses string comparison to find the region, so the result * should be cached rather than calling this method multiple times. * @return The region, or null. */
    public AtlasRegion findRegion (String name) {
        for (int i = 0, n = regions.size; i < n; i++)
            if (regions.get(i).name.equals(name)) return regions.get(i);
        return null;
    }

    /** Returns all regions with the specified name, ordered by smallest to largest {@link AtlasRegion#index index}. This method * uses string comparison to find the regions, so the result should be cached rather than calling this method multiple times. */
    public Array<AtlasRegion> findRegions (String name) {
        Array<AtlasRegion> matched = new Array();
        for (int i = 0, n = regions.size; i < n; i++) {
            AtlasRegion region = regions.get(i);
            if (region.name.equals(name)) matched.add(new AtlasRegion(region));
        }
        return matched;
    }

测试用例，从网上找了4张图片，用TexturePacker打包之后如下图：

注意，用工具打包之后会生成2个文件.atlas和.png 2个文件，2个文件都需要拷贝到工程目录下，atlas文件是对png文件的描述。

    TextureAtlas atlas;
    AtlasRegion baidu, kugou, xiami, kuwo;
    SpriteBatch batch;

    @Override
    public void create() {
        atlas = new TextureAtlas(Gdx.files.internal("textureatlas.atlas"));
        baidu = atlas.findRegion("baidu");
        kugou = atlas.findRegion("kugou");
        xiami = atlas.findRegion("xiami");
        kuwo = atlas.findRegion("kuwo");

        batch = new SpriteBatch();
    }

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

        batch.begin();
        batch.draw(baidu, 10, 10);
        batch.draw(kugou, 320, 240);
        batch.draw(xiami, 10, 240);
        batch.draw(xiami, 320, 10);
        batch.end();

    }

    @Override
    public void dispose() {
        atlas.dispose();
        batch.dispose();
    }

测试结果