blocks|key|249562|text|如果您想隐藏转换，并且在设置它一次之后不去考虑它，您可以创建一个继承所有所需功能的类，但在将其传递给父类的函数之前，首先转换坐标。不幸的是，这会花费很多时间。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|249563|或者，您也可以创建一个方法，对整个Coordinate对象(或您正在使用的任何对象)执行简单的y'+=+height+-+y转换，并在每次操作之前调用它一次。|offset|length|style|CODE|249564|entityMap^0|0|H|A|1B|F|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|I|$]]

If you want to hide the transformation and not think about it after setting it up once, you can make a class that inherits all of the functionalities you need, but first transforms the coordinates before passing it to its parent class's function. Unfortunately, this would take a lot of time. 

You could alternatively make a method that does the simple <code>y' = height - y</code> transformation on the whole <code>Coordinate</code> object (or whatever it is you're using), and call it once before each operation.

blocks|key|253132|text|我想说，这图形库很有趣。我从下面的链接中找到了这个评估：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|253133|253134|+另一个问题是，在Libgdx的不同部分使用了不同的坐标系。有时轴的原点在左下角，y轴指向上，有时在精灵的左上角指向下。绘制网格时，原点甚至位于屏幕的中心。这造成了相当多的混乱和额外的工作，以使一切都在屏幕上的正确位置。|blockquote|offset|length|style|BOLD|253135|253136|253137|http://www.csc.kth.se/utbildning/kandidatexjobb/datateknik/2011/rapport/ahmed_rakiv_OCH_aule_jonas_K11072.pdf|253138|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1|S|0|0|0|0|31|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|V|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|W|8|@$F|X|G|Y|H|I]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|11|8|@]|9|@$F|12|G|13|1|14]]|A|$]]|$1|N|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|O|$P|$5|Q|R|S|A|$T|M]]]]

Interesting graphics library, I would say. I found this assessment from the link below:

<blockquote>
 Another issue was that different coordinate systems were used in different parts of Libgdx. Sometimes the origin of the axes was in the
 bottom left corner with the y-axis pointing upwards and sometimes in
 the top left corner of the sprite pointing downwards. When drawing
 Meshes the origin was even in the center of the screen. This caused
 quite a bit of confusion and extra work to get everything in the
 correct place on the screen.
</blockquote>

<a href="http://www.csc.kth.se/utbildning/kandidatexjobb/datateknik/2011/rapport/ahmed_rakiv_OCH_aule_jonas_K11072.pdf" rel="noreferrer">http://www.csc.kth.se/utbildning/kandidatexjobb/datateknik/2011/rapport/ahmed_rakiv_OCH_aule_jonas_K11072.pdf</a>

blocks|key|3146726|text|如果你使用相机(你应该这样做)，改变坐标系是非常简单的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3146727|camera=+new+OrthographicCamera(Gdx.graphics.getWidth(),+Gdx.graphics.getHeight());
camera.setToOrtho(true,+Gdx.graphics.getWidth(),+Gdx.graphics.getHeight());|code-block|syntax|javascript|3146728|如果您使用TextureRegions和/或TextureAtlas，那么您需要做的就是调用region.flip(false，true)。|3146729|默认情况下，我们使用y-up的原因(您可以轻松更改，如上图所示)如下：|3146730|你的模拟代码很可能会使用标准的欧几里得坐标系和y-up+|3146731|，如果你是3D的，你有y-up|unordered-list-item|3146732|
|3146733|，默认的坐标系是OpenGL中的右手坐标系，y-up。当然，你可以通过一些矩阵魔术轻松地改变这一点。|3146734|3146735|在libgdx中，我们使用y-down的地方只有两个：|3146736|向下事件像素图坐标(左上角原点，以窗口坐标形式给出的事件坐标(左上角原点，y向下)|3146737|同样，您可以使用相机或少量矩阵数学轻松地将使用的坐标系更改为您想要的任何坐标系。|3146738|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|15|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|17|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|18|8|@]|9|@]|A|$]]|$1|R|3|S|5|O|7|19|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1B|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|1D|8|@]|9|@]|A|$]]|$1|10|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|11|$]]

If you use a Camera (which you should) changing the coordinate system is pretty simple:

<pre><code>camera= new OrthographicCamera(Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
camera.setToOrtho(true, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
</code></pre>

If you use TextureRegions and/or a TextureAtlas, all you need to do in addition to that is call region.flip(false, true). 

The reasons we use y-up by default (which you can easily change as illustrated above) are as follows:

<ul>
<li>your simulation code will most likely use a standard euclidian coordinate system with y-up</li>
<li>if you go 3D you have y-up</li>
<li>The default coordinate system is a right handed one in OpenGL, with y-up. You can of course easily change that with some matrix magic.</li>
</ul>

The only two places in libgdx where we use y-down are:

<ul>
<li>Pixmap coordinates (top upper left origin, y-down)</li>
<li>Touch event coordinates which are given in window coordinates (top upper left origin, y-down)</li>
</ul>

Again, you can easily change the used coordinate system to whatever you want using either Camera or a tiny bit of matrix math.

blocks|key|2932048|text|只是稍微扩展一下上面说的坏逻辑，如果你正在使用TextureAtlas+(带TextureRegions)，你需要翻转它们，就像坏逻辑说的那样，除了相机工作。如果您使用的是TextureAtlas，则可以在加载地图集后立即使用此代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2932049|String+textureFile+=+"data/textures.txt";++
atlas+=+new+TextureAtlas(Gdx.files.internal(textureFile),+Gdx.files.internal("data"));++
//+Let's+flip+all+the+regions.++Required+for+y=0+is+TOP
Array<AtlasRegion>+tr+=+atlas.getRegions();++++++
for+(int+i+=+0;+i+<+tr.size;+i%2B%2B)+{
++TextureRegion+t+=+tr.get(i);
++t.flip(false,+true);
}|code-block|syntax|javascript|2932050|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Just to expand a little on what badlogic said above, if you are using a TextureAtlas (with TextureRegions) you need to flip them, as badlogic said, in addition to the camera work. If you are using a TextureAtlas, you can use this code right after loading your atlas: 

<pre><code>String textureFile = "data/textures.txt"; 
atlas = new TextureAtlas(Gdx.files.internal(textureFile), Gdx.files.internal("data")); 
// Let's flip all the regions. Required for y=0 is TOP
Array&lt;AtlasRegion&gt; tr = atlas.getRegions(); 
for (int i = 0; i &lt; tr.size; i++) {
 TextureRegion t = tr.get(i);
 t.flip(false, true);
}
</code></pre>

blocks|key|2932074|text|我能够通过OrthographicCamera使用建议的翻转坐标系正确地渲染纹理和字体。下面是我所做的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2932075|private+SpriteBatch+batch;
private+BitmapFont+font;
private+OrthographicCamera+cam;
private+Texture+tex;

@Override
public+void+create+()+{
++++batch+=+new+SpriteBatch();
++++
++++font+=+new+BitmapFont(true);
++++font.setColor(Color.WHITE);
++++
++++cam+=+new+OrthographicCamera(Gdx.graphics.getWidth(),+Gdx.graphics.getHeight());
++++cam.setToOrtho(true,+Gdx.graphics.getWidth(),+Gdx.graphics.getHeight());
++++tex+=+new+Texture("badlogic.jpg");
}

@Override
public+void+dispose()+{
++++batch.dispose();
++++font.dispose();
++++tex.dispose();
}

@Override
public+void+render+()+{
++++cam.update();
++++batch.setProjectionMatrix(cam.combined);
++++
++++Gdx.gl.glClearColor(0,+0,+0,+1);
++++Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
++++batch.begin();
++++
++++font.draw(batch,+"Test",+50,+50);
++++batch.draw(tex,+100,+100,+tex.getWidth(),+tex.getHeight(),+0,+0,+tex.getWidth(),+tex.getHeight(),+false,+true);
++++
++++batch.end();
}|code-block|syntax|javascript|2932076|需要注意的重要事项是：|2932077|对于BitmapFont构造函数，布尔值翻转字体|2932078|+batch.draw()您需要使用所有这些参数，因为在末尾需要一个布尔值flipY来翻转纹理(我可以扩展SpriteBatch或创建一个实用方法，以避免总是传递这么多参数。)|unordered-list-item|2932079|
|2932080|Notice+batch.setProjectionMatrix()|2932081|2932082|现在，我们将看到我是否会在今晚晚些时候回到这里，进行编辑，以修复所有这些问题或发现。|2932083|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|M|7|10|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|11|8|@]|9|@]|A|$]]|$1|P|3|Q|5|M|7|12|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

I was able to get textures and fonts rendering correctly using the suggested flipped coordinate system via OrthographicCamera. Here's what I did:
<pre><code>private SpriteBatch batch;
private BitmapFont font;
private OrthographicCamera cam;
private Texture tex;

@Override
public void create () {
 batch = new SpriteBatch();
 
 font = new BitmapFont(true);
 font.setColor(Color.WHITE);
 
 cam = new OrthographicCamera(Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
 cam.setToOrtho(true, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
 tex = new Texture(&quot;badlogic.jpg&quot;);
}

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

@Override
public void render () {
 cam.update();
 batch.setProjectionMatrix(cam.combined);
 
 Gdx.gl.glClearColor(0, 0, 0, 1);
 Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
 batch.begin();
 
 font.draw(batch, &quot;Test&quot;, 50, 50);
 batch.draw(tex, 100, 100, tex.getWidth(), tex.getHeight(), 0, 0, tex.getWidth(), tex.getHeight(), false, true);
 
 batch.end();
}
</code></pre>
Important things to notice are:
<ul>
<li>The BitmapFont constructor, the boolean flips the font</li>
<li>For batch.draw() you need to use all those parameters because you need a boolean flipY at the end to flip the texture (I may extend SpriteBatch or make a utility method to avoid passing so many parameters all the time.)</li>
<li>Notice batch.setProjectionMatrix(cam.combined); in render()</li>
</ul>
Now we will see if I am back here later tonight doing edits to fix any other issues or discoveries with doing all this.

blocks|key|251237|text|我刚刚创建了一个类，它扩展了添加y+=+Gdx.graphics.getHeight()+-+y+-+height的某些方法的SpriteBatch。简单但有效。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|251238|entityMap^0|G|15|1R|B|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

I just made a class that extends <code>SpriteBatch</code> that overides certain methods adding <code>y = Gdx.graphics.getHeight() - y - height</code>. Simple but effective.

LibGDX has a coordinate system where (0,0) is at the bottom-left. (like this image: <a href="https://i.stack.imgur.com/jVrJ0.png" rel="noreferrer">http://i.stack.imgur.com/jVrJ0.png</a>) 

This has me beating my head against a wall, mainly because I'm porting a game I had already made with the usual coordinate system (where 0,0 is in the Top Left Corner).

My question: Is there any simple way of changing this coordinate system?

Changing the Coordinate System in LibGDX (Java)

LibGDX有一个坐标系，其中(0,0)位于左下角。(如下图：)这让我很头疼，主要是因为我移植了一个我已经用通常的坐标系(其中0,0在左上角)制作的游戏。我的问题是：有什么简单的方法可以改变这个坐标系吗？

问更改LibGDX中的坐标系(Java)
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