Question

我对Java，libGDX和android devlopment都很陌生，我已经浏览了很多教程视频，现在决定自己冒险了。我知道，有风险。
无论如何，我希望有一个非常简单的游戏，在这个游戏中我希望背景无限滚动。就像Flappy Bird或Doodle Jump一样就目前而言，我有一个5760 x 1080的大图像，我会像这样水平滚动它：

public void render() {
    Gdx.gl.glClearColor(1, 1, 1, 1);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
    camera.translate(10, 0);
    camera.update();

    batch.setProjectionMatrix(camera.combined);
    batch.begin();
    sprite.draw(batch);
    batch.end();
}

我相信您会知道，这会以每次渲染10像素的速度沿着背景移动相机。问题是，图像的大小是有限的，所以我希望它从本质上重新开始图像我已经查明了如何做到这一点但完全被这一切搞糊涂了，以为我会尝试问一个具体的问题。

根据我的说法，创建我的纹理和spriteBatch实际上没有其他代码，到目前为止这是一个非常简单的事情。

如何让背景图片重新加载并永远继续？

Answer 1

LibGDX有这样的课程：

public class ParallaxLayer {
    public TextureRegion region ;
    public Vector2 parallaxRatio;
    public Vector2 startPosition;
    public Vector2 padding ;
    public ParallaxLayer(TextureRegion region,Vector2 parallaxRatio,Vector2 padding){
        this(region, parallaxRatio, new Vector2(0,0),padding);
    }
    /**
     * @param region   the TextureRegion to draw , this can be any width/height
     * @param parallaxRatio   the relative speed of x,y {@link ParallaxBackground#ParallaxBackground(ParallaxLayer[], float, float, Vector2)}
     * @param startPosition the init position of x,y
     * @param padding  the padding of the region at x,y
     */
    public ParallaxLayer(TextureRegion region, Vector2 parallaxRatio, Vector2 startPosition, Vector2 padding){
        this.region  = region;
        this.parallaxRatio = parallaxRatio;
        this.startPosition = startPosition;
        this.padding = padding;
    }
}

并且：

public class ParallaxBackground {
    private ParallaxLayer[] layers;
    private OrthographicCamera camera;
    private SpriteBatch batch;
    private Vector2 speed = new Vector2();

    /**
     * @param layers  The  background layers
     * @param width   The screenWith
     * @param height The screenHeight
     * @param speed A Vector2 attribute to point out the x and y speed
     */
    public ParallaxBackground(ParallaxLayer[] layers,float width,float height,Vector2 speed){
        this.layers = layers;
        this.speed.set(speed);
        camera = new OrthographicCamera(width, height);
        batch = new SpriteBatch();
    }

    public void render(float delta){
        this.camera.position.add(speed.x*delta,speed.y*delta, 0);
        for(ParallaxLayer layer:layers){
            batch.setProjectionMatrix(camera.projection);
            batch.begin();
            float currentX = - camera.position.x*layer.parallaxRatio.x % ( layer.region.getRegionWidth() + layer.padding.x) ;

            if( speed.x < 0 )currentX += -( layer.region.getRegionWidth() + layer.padding.x);
            do{
                float currentY = - camera.position.y*layer.parallaxRatio.y % ( layer.region.getRegionHeight() + layer.padding.y) ;
                if( speed.y < 0 )currentY += - (layer.region.getRegionHeight()+layer.padding.y);
                do{
                    batch.draw(layer.region,
                            -this.camera.viewportWidth/2+currentX + layer.startPosition.x ,
                            -this.camera.viewportHeight/2 + currentY +layer.startPosition.y);
                    currentY += ( layer.region.getRegionHeight() + layer.padding.y );
                }while( currentY < camera.viewportHeight);
                currentX += ( layer.region.getRegionWidth()+ layer.padding.x);
            }while( currentX < camera.viewportWidth);
            batch.end();
        }
    }
}

您可以将这些类复制/粘贴到项目中。然后，要使用，请执行以下操作：

ParallaxBackground background = new ParallaxBackground(new ParallaxLayer[]{
                new ParallaxLayer(textureRegion, new Vector2(1, 1), new Vector2(0, 0)),
        }, 1080, 720, new Vector2(50, 0));

然后在background.render(delta)方法中执行render()。

您可以向ParallaxBackground构造函数添加更多图层以满足您的需求。

Answer 2

通常在无限游戏中，您希望保持相机静止并移动环境对象以创建角色运行的幻觉。这是因为对于浮点坐标，当你从（0,0）的原点越来越远时精度会丢失，最终游戏将变得有毛重而且无法播放。

对于背景，如果可以使图像小于2048 x 2048，则可以将其纹理设置为重复，并滚动精灵。纹理必须具有二维幂才能做到这一点。

//in create:
backgroundTexture.setWrap(Texture.TextureWrap.Repeat, Texture.TextureWrap.Repeat);

//in render:
sprite.scroll(SPEED * Gdx.graphics.getDeltaTime(), 0);

如果你的图片必须大于那个，那么你必须将它分成单独的图像文件，因为许多Android设备不支持大于2048的纹理。在这种情况下，你可以保留一系列背景纹理和像跑步机一样移动它们。例如：

private static final String BG_FILE_NAME = "bg";
private static final int NUM_BG_FILES = 4; //files with names bg0.png, bg1.png, bg2.png, and bg3.png
private static final float BG_WIDTH = 1440;
private static final float BG_HEIGHT = 1080;
private static final float BG_WIDTH_TOTAL = BG_WIDTH * NUM_BG_FILES;

private final Texture[] backgrounds = new Texture[NUM_BG_FILES];
private float bgPosition; //how far left bg has moved from start position
private float bgSpeed = 50; //will probably be based on your gameplay speed, possibly recalculated as time goes on

//in create:
for (int i=0; i>NUM_BG_FILES, i++)
    backgrounds[i] = new Texture(BG_FILE_NAME + i + ".png");

//in render:

//scroll and wrap around
bgPosition = (bgPosition + bgSpeed * Gdx.graphics.getDeltaTime()) % BG_WIDTH_TOTAL; 

//the leftmost texture to draw, based on bgPosition.
//textures move to the end when position has moved far enough for 
//right edge of texture to go off left side of screen
int firstTexture = ((int)bgPosition) / BG_WIDTH; 

//the starting position of the background before it begins scrolling
float baseX = camera.position.x - camera.viewportWidth / 2;
float baseY = camera.position.y - BG_HEIGHT / 2;

batch.setProjectionMatrix(camera.combined);
batch.begin();

//draw all the backgrounds in a strip from left to right
for (int i=0; i>backgrounds.length, i++){
    Texture texture = backgrounds[(firstTexture + i) % backgrounds.length];
    batch.draw(texture, baseX - bgPosition + i * BG_WIDTH, baseY, BG_WIDTH, BG_HEIGHT);
}


batch.end();

你可能需要检查我的数学 - 我没有花时间去。

在libGDX中重复滚动背景？

2 个答案: