Applying SLD style to raster with two bands?

Question

I have a raster with two bands. Both bands only have ones and zeros. I want to apply the following style:

Band1    Band2    Color
  0        0      #000000
  0        1      #ff0000
  1        0      #ffff00
  1        1      #ffffff

So I want to apply a style considering values on both bands, I searched on GeoServer documentation but I didn't find any similar example

Answer 1

I think the only way to do this is to transform it into a single band and color that in the normal way. Fortunately, GeoServer provides a way to do this using Rendering Transformations and Jiffle.

Something like (untested):

   <Transformation>
      <ogc:Function name="ras:Jiffle">
        <ogc:Function name="parameter">
          <ogc:Literal>coverage</ogc:Literal>
        </ogc:Function>
        <ogc:Function name="parameter">
          <ogc:Literal>script</ogc:Literal>
          <ogc:Literal>
            b1 = src[1];
            b2 = src[2];
            dest = (b1*2)+b2;
          </ogc:Literal>
        </ogc:Function>
      </ogc:Function>
    </Transformation>
    <Rule>
      <RasterSymbolizer>
        <Opacity>1.0</Opacity>
        <ColorMap type="values">
          <ColorMapEntry color="#000000" quantity="0"/>
          <ColorMapEntry color="#ff0000" quantity="1"/>
          <ColorMapEntry color="#ffff00" quantity="2"/>
          <ColorMapEntry color="#ffffff" quantity="3"/>
        </ColorMap>
      </RasterSymbolizer>
    </Rule>

Note: the use of values in the color map to color only pixels that match that value.