What are the difference between landscape layer blend types?

Development Rendering
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I am new to computer game graphics and terminology. I don’t have problems reading the C++ programming documentation of unreal engine, however when it comes to rendering and graphics, I feel like I am reading a medical drug prescription.

First things first. I have several question, the most important one is the one as the title of this question. I am now trying to learn the basics of creating landscapes.

1-) What are the difference between those layer blend types? (LB_Alpha_Blend, LB_Weight_Blend and LB_Height_Blend)

119981-blendtype.png
119981-blendtype.png368×769 131 KB

2-) On what use case, what type should I choose?

3-) I have seen that when we choose LB_Height_Blend, we get a second pin in layer blend node. We put there the alpha channel of the texture we work with. Why alpha channel? Why not red, green or blue, or even whole RGBA, but alpha? What does role alpha channel take in this situation?

119982-blendtype.png

4-) Is there any book or website that can teach me all these terminology that is used in gaming graphics? Such as ambient occlusion, diffuse, specular etc.

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No answer to a simple question? Advanced users? :frowning:

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I was looking for an answer to the same question and found this page, which explains it in more detail:

I have the feeling that I didn’t quite understand it to the fullest yet, so I am not trying to explain anything here, as I may be utterly wrong. I, however, hope that the page may help you understand it a little better.

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  1. Alpha Blend, means a layer, which is blended in a mask-like fashion. This layer is not dependent on any other layers.
    Weight blend means a layer, which is blended with other layers. Sum of all weight-blended layers on any point of your landscape is always 1.
    Height blend is the same as weighblend, but with ability to add a mask, to make transition between layers more complex and visually interesting.

  2. Typically, you might want to use height-blended or weight-blended layers to define surfaces of your landscape and use alpha alpha blended layers for certain details, like localized puddles, for example.

  3. You are expected to input a greyscale blend mask there. It is irrelevant which channel or which texture it is stored in.

  4. There are numerous books and resources, but eventually, you can learn everything as you try.

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