I took the Textured Sphere example as a starting point and applied these displacement GLSL shaders to them using the GLSLshader class. The Sampler2D input for the vertex shader is a displacementMap and the input for the fragment shader is a colorMap. It runs without errors, it correctly displaces the vertices and it shows the texture (see the above image). But my question is with regard to which texture is used.

I noticed that the input textures you supply via the shader have no effect.

1.   shader.start();
2.   shader.setTexUniform("colorMap", tex2); // is not used, delete this and the endresult is unchanged
   
3.   shader.setTexUniform("displacementMap", tex2); // idem
4.   renderer.model(earth);
5.   shader.stop();

The texture that is used is the one set in the GLModel.

1.   earth.initTextures(1);
2.   earth.setTexture(0, tex); // used for both the colorMap and the displacementMap?
3.   earth.updateTexCoords(0, texCoords);