How do I pass textures into a fragment shader in Slick?

Question

I've written a shader that uses three different textures, tex0, tex1, and tex2. I can load it into Slick and successfully display it, but I can't figure out how to set the three different textures. Whichever texture I last load or set is the one used for all three.

My code:

if (sp == null) {
    try {
        sp = ShaderProgram.loadProgram("passthrough.vert", "planet.frag");
        planet = TextureLoader.getTexture("png", new FileInputStream("earth.png"));
        clouds = TextureLoader.getTexture("png", new FileInputStream("clouds.png"));
        lights = TextureLoader.getTexture("png", new FileInputStream("lights.png"));
    } catch (Exception e) {
        e.printStackTrace();
        System.exit(0);
    }
}

sp.bind();

// Attempt to set tex0-tex2. This fails and just sets everything to tex2.
glUniform1i(sp.getUniform1i("tex0"), 0);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, planet.getTextureID());

glUniform1i(sp.getUniform1i("tex1"), 1);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, clouds.getTextureID());

glUniform1i(sp.getUniform1i("tex2"), 0);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, lights.getTextureID());

sp.setUniform1f("time", tick * 0.03f);
sp.setUniform2f("resolution", 400f, 400f);

// Render a quad. This works, except that the textures are all the same.
glBegin(GL_QUADS);
glVertex2i(0, 0);
glVertex2i(0, 400);
glVertex2i(400, 400);
glVertex2i(400, 0);
glEnd();

Answer 1

OK, it turns out that instead of

glUniform1i(sp.getUniform1i("tex0"), 0);

I should be using eg

sp.setUniform1i("tex0", 0);