如何在 LibGDX 中进行混合 [英] How to do blending in LibGDX
问题描述
我基本上想在 LibGDX 中使用混合模式，但不知道该怎么做.我在互联网上找到了这张图片.我想在 LibGDX 上做同样的事情.谁能教教我.
I basically want to play around with blending modes in LibGDX but don't know how to do it. I found this image on internet. I want to do the same thing on LibGDX. Can someone teach me how.
我一直在使用 Scene2D.这是我的非工作片段.
I've been playing around using Scene2D. Here's my non-working snippet.
private class MyGroup extends Group {
Image red, blue;
public MyGroup() {
Texture texture = new Texture(Gdx.files.internal("images/red.png"));
texture.setFilter(TextureFilter.Linear, TextureFilter.Linear);
red = new Image(texture);
texture = new Texture(Gdx.files.internal("images/blue.png"));
texture.setFilter(TextureFilter.Linear, TextureFilter.Linear);
blue = new Image(texture);
red.setX(-25);
blue.setX(25);
}
@Override
public void draw(Batch batch, float parentAlpha) {
batch.end();
batch.begin();
batch.enableBlending();
red.draw(batch, parentAlpha);
Gdx.gl.glEnable(Gdx.gl20.GL_BLEND);
Gdx.gl.glBlendFuncSeparate(
Gdx.gl20.GL_DST_COLOR,
Gdx.gl20.GL_SRC_COLOR,
Gdx.gl20.GL_ONE,
Gdx.gl20.GL_ONE);
blue.draw(batch, parentAlpha);
}
}
推荐答案
我意识到这不是一个新问题，但我想我会与其他任何人分享一些信息，他们在不了解渲染的情况下解决了这个问题/答案在 OpenGL 中(了解这些术语有很大帮助，因此您不仅仅是猜测混合和匹配)请注意 这个网站是我自己学到的大部分内容，因此可以在那里找到更完整的信息.
I realize this is not a new question, but I thought I would share some information for anyone else who makes it to this question/answer without knowing much about rendering in OpenGL (Knowing these terms helps a lot so you aren't just guessing mix-and-matching) Note that this site is how I learned most of this myself, so more complete information can be found there.
目标颜色:缓冲区中的颜色，除非被修改或被新值覆盖，否则(最终)会被绘制.
Destination Color: the color in the buffer, which will (eventually) be drawn unless it is modified or overwritten with new values.
源颜色:来自附加渲染命令的颜色，可能与目标颜色交互，也可能不交互(取决于我们的设置)
Source Color: the color coming in from additional rendering commands, which may or may not interact with the destination color (depending on our settings)
默认混合方程: Final Color = (SourceColor*SourceBlendingFactor)+(DestinationColor*DestinationBlendingFactor) (这个默认方程可以改变，但我建议阅读我的源链接在顶部了解更多信息)
The default blending equation: Final Color = (SourceColor*SourceBlendingFactor)+(DestinationColor*DestinationBlendingFactor) (This default equation can be changed, but I recommend reading my source link at the top for more information on that)
这两个 BlendingFactors 是我们可以处理的.我们可以将它们设置为:
The two BlendingFactors are what we can mess with. We can set them to:
GL_ZERO:RGB(0,0,0) A(0)
GL_ONE:RGB(1,1,1) A(1)
GL_SRC_COLOR:RGB(sourceR, sourceG, sourceB) A(sourceA)
GL_ONE_MINUS_SRC_COLOR:RGB(1-sourceR, 1-sourceG, 1-sourceB) A(1-sourceA)
GL_DST_COLOR:RGB(目的地R，目的地G，目的地B)A(目的地A)
GL_ONE_MINUS_DST_COLOR:RGB(1-destinationR, 1-destinationG, 1-destinationB) A(1-destinationA)
GL_SRC_ALPHA:RGB(sourceA, sourceA, sourceA) A(sourceA)
GL_ONE_MINUS_SRC_ALPHA:RGB(1-sourceA, 1-sourceA, 1-sourceA) A(1-sourceA)
GL_DST_ALPHA:RGB(目的地A，目的地A，目的地A)A(目的地A)
GL_ONE_MINUS_DST_ALPHA:RGB(1-destinationA, 1-destinationA, 1-destinationA) A(1-destinationA)
GL_SRC_ALPHA_SATURATE:RGB(min(sourceA, 1-destinationA), min(sourceA, 1-destinationA), min(sourceA, 1-destinationA)) A(1)
下面也使用了一些预定义的常量颜色，默认是黑色
GL_CONSTANT_COLOR:RGB(constantR,constantG,constantB)A(constantA)
GL_ONE_MINUS_CONSTANT_COLOR:RGB(1-constantR, 1-constantG, 1-constantB) A(1-constantA)
GL_CONSTANT_ALPHA:RGB(constantA,constantA,constantA)A(constantA)
GL_ONE_MINUS_CONSTANT_ALPHA:RGB(1-constantA, 1-constantA, 1-constantA) A(1-constantA)
GL_ZERO: RGB(0,0,0) A(0)
GL_ONE: RGB(1,1,1) A(1)
GL_SRC_COLOR: RGB(sourceR, sourceG, sourceB) A(sourceA)
GL_ONE_MINUS_SRC_COLOR: RGB(1-sourceR, 1-sourceG, 1-sourceB) A(1-sourceA)
GL_DST_COLOR: RGB(destinationR, destinationG, destinationB) A(destinationA)
GL_ONE_MINUS_DST_COLOR: RGB(1-destinationR, 1-destinationG, 1-destinationB) A(1-destinationA)
GL_SRC_ALPHA: RGB(sourceA, sourceA, sourceA) A(sourceA)
GL_ONE_MINUS_SRC_ALPHA: RGB(1-sourceA, 1-sourceA, 1-sourceA) A(1-sourceA)
GL_DST_ALPHA: RGB(destinationA, destinationA, destinationA) A(destinationA)
GL_ONE_MINUS_DST_ALPHA: RGB(1-destinationA, 1-destinationA, 1-destinationA) A(1-destinationA)
GL_SRC_ALPHA_SATURATE: RGB(min(sourceA, 1-destinationA), min(sourceA, 1-destinationA), min(sourceA, 1-destinationA)) A(1)
The following also uses some predefined constant color, by default it is black
GL_CONSTANT_COLOR: RGB(constantR, constantG, constantB) A(constantA)
GL_ONE_MINUS_CONSTANT_COLOR: RGB(1-constantR, 1-constantG, 1-constantB) A(1-constantA)
GL_CONSTANT_ALPHA: RGB(constantA, constantA, constantA) A(constantA)
GL_ONE_MINUS_CONSTANT_ALPHA: RGB(1-constantA, 1-constantA, 1-constantA) A(1-constantA)
所以所有这些都只是预定义的浮点值，它们与我们的源或目标相乘，然后相加.
So all of these are just predefined float values that are being multiplied with either our source or destination, and then added to the other.
从图中最容易观察到的是 GL_ZERO 和 GL_ONE.我们最终得到具有 ONE 的图像.
The easiest to observe from the image is GL_ZERO and GL_ONE. We end up with whichever image has the ONE.
用 GL_DST_COLOR 理解 GL_ZERO
Understanding GL_ZERO with GL_DST_COLOR
当 GL_ZERO 在目标上时，我们将忽略当前缓冲区中的任何颜色信息(因为将所有内容乘以零).然而，由于源图像上也有 GL_DST_COLOR，我们最终将源图像和目标图像的 r、g、b、a 值相乘.
When GL_ZERO is on the destination, we are ignoring any color information currently in the buffer (because multiplying everything by zero). However, With GL_DST_COLOR also on the source image, we end up multiplying the r, g, b, a values of the source and destination.
由于示例图像的性质，这在图像中看起来不错.一个作为纯色图像，而另一个灰度图像看起来和行为几乎就像一束光束来揭示"GL_ZERO 设置中的颜色.
This looks good in the image because of the nature of the example images. One acts as a solid color image, while the other grayscale image looks and acts almost like a beam of light to "reveal" the color out from our GL_ZERO setting.
希望这有助于解释我们在上面看到的图像，并帮助每个人了解这些图像实际上是如何混合在一起的.
Hopefully, this helps explain the images we can see above and helps everyone understand how those images are actually being blended together.
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