Question

How to turn off multiple texture units because they influence to other render parts.
I activate my them:

        glActiveTexture(GL_TEXTURE0 + index);
        glBindTexture(GL_TEXTURE_2D,
               ((MaterialSampler2D)specular).texture.getTOB());
        shader.setTexture2(index);

Is there something like glDeactivateTexture?

Answer 1

glActiveTexture does not activate texture-units. It merely selects which texture-unit you’re currently modifying (yes, OpenGL’s object state managing is horrible).
You activate textures with glEnable(<texture-target>) and glDisable(<texture-target>). In your case, the target would be GL_TEXTURE_2D.

So to answer your question: Select the texture-unit i by using glActiveTexture(GL_TEXTURE0+i) and then disable it with glDisable(GL_TEXTURE_2D).

Note that all this is redundant with shaders – you can just not access the values there.