Best way to overlay a texture with alpha?

What is the best way to overlay a texture with an alpha map to a material that’s got a diffuse map already defined? I’m using the Light Map field right now but it’s sorta darkening the whole material too much.

Also, I was wondering if it was possible to configure the “intensity” of the overlaid map, i.e. make it so I can set an intensity of like 0.7 and the overlaid map will be slightly less visible. Like setting it’s alpha to 0.7/1.0. Hopefully I explained that well.

Thanks for any help in advance!

You mean to overlay it fro black to texture ? or from transparent to texture? For the second i would use alphamap.

I’m not sure if I explained my goal well enough. I’ll give the example:

I have a wall texture. I want to add a crack-like texture over that one. The crack-like texture already has the alpha map and everything defined. I’m trying to make it so only the visible parts of the texture are added over the current. I figured there’d be a way to easily do this. So far light map’s the only thing I can seem to use. :confused:

You’ll have to use your own shader to do this. The light map is mutiplied to the diffuse map. That’s not what you want.

@vinexgames hello man.

There is LightBlow shader which can make it. You can use vertexColors or RGB texture for masking.


To install the shader you will need to install a JME plugin “shaderblowlib”. This is JME contribution plugin. Also, you will need to get nightly builds to get all fixed shaders.

Then you will need to add the plugin library to your project and it will work.

There is the shaderBlow project with many examples.

Just ask me if you have any problems…


You can also search for "“decals” or “screen space decals”. It can get somewhat complex to solve.

@jmaasing said:
You can also search for ""decals" or "screen space decals". It can get somewhat complex to solve.

That's basically what I have but I'm trying to overlay the decal to the main texture. It's not necessarily a decal, but a whole texture I want to overlay.

@mifth That looks like what I'll need. I'm at school right now but I'll fiddle with it when I get home in a few hours. Hopefully I can have some stuff to show off before the end of the weekend. :D