libgdx无法绘制精灵

Question

I am trying really hard to draw a sprite with LibGDX, but I fail. If you need more than the snippets, the source is here: https://github.com/reisi007/Planes2DLibGDX/blob/master/Main/src/com/reisisoft/Planes2D/Planes2D.java

So, what am I doing? I am loading a PNG (1024x1024) and creating sprites, which I put in a Map. This map I put in a map again (later different resolutions)

 private void putTextures(Resolutions resolutions) {
    Map<GObjects, Sprite> map;
    switch (resolutions) {
        case MidRes:
            map = new EnumMap<GObjects, Sprite>(GObjects.class);
            map.put(GObjects.PlaneR, new Sprite(txtMidRes, 0, 0, 600, 278));
            map.put(GObjects.PlaneG, new Sprite(txtMidRes, 0, 278, 600, 278));
            map.put(GObjects.PlaneB, new Sprite(txtMidRes, 0, 556, 600, 104));
            map.put(GObjects.Grass, new Sprite(txtMidRes, 0, 834, 600, 104));
            map.put(GObjects.Bullet, new Sprite(txtMidRes, 600, 834, 299, 138));
            all.put(Resolutions.MidRes, map);
            break;
    }
}

There is a function I get a sprite from the current resolutions:

private boolean setCurrentResolutions(Resolutions resolution) {
    if (resolution == null)
        return false;
    currentResolution = resolution;
    currentResolutionSprites = all.get(Resolutions.MidRes);
    return true;
}

private Sprite requestSprite(GObjects gObject) {
    return currentResolutionSprites.get(gObject);
}

I am testing the Winows build, whichs size is 800x480. The origin of the sprite I want to draw is: X 300.0 Y 139.0 The width is 300, height is 140. Next the render function:

public void render() {
    camera.update();
    spriteBatch.setProjectionMatrix(camera.combined);
    Update();
    spriteBatch.begin();
    Draw();
    spriteBatch.end();
}

As this is not really helping, here the Draw method:

public void Draw() {
    s.draw(spriteBatch);
}

What I see is just black. I tried with OpenGL 1,1.1,2 and various solution from StackOverflow

Finally the "create" method:

// On creation
public void create() {
    curH = Gdx.graphics.getHeight();
    curW = Gdx.graphics.getWidth();
    camera = new OrthographicCamera(curW, curH);
    spriteBatch = new SpriteBatch();
    // Load texture
    txtMidRes = new Texture(Gdx.files.internal("planes.png"));
    txtMidRes.setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear);
    // Create Sprites for EVERY supported resolution
    putTextures(Resolutions.MidRes);
    // Set resolution according to H/W
    setCurrentResolutions(Resolutions.MidRes);
    s = requestSprite(GObjects.PlaneR);
    s.setSize(300, 140);
    s.setPosition(Gdx.graphics.getWidth() / 2 - s.getWidth() / 2,
            Gdx.graphics.getHeight() / 2 - s.getHeight() / 2);
}

Thanks for helping

Florian

Answer 1

First of all, the link you provided to the full source doesn't match the snippets there. Maybe there is a forgotten push ?

Now some ideas on your issue :

• You haven't set the camera position. Try :

  camera.position.set(curH / 2f, curW / 2f, 0);

• You don't need to build your sprites manually, libgdx provides features to do that. See Texture packer on the official doc.

• You can also handle resolutions automatically with AssetManager . See this post for more information.