gdx.java

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.backends.lwjgl3.Lwjgl3Application;
import com.badlogic.gdx.backends.lwjgl3.Lwjgl3ApplicationConfiguration;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.ui.Label;

import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.scenes.scene2d.Actor;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL20;

class MyActor extends Actor {
    @Override
    public void draw(Batch batch, float parentAlpha) {
        super.draw(batch, parentAlpha);

        int cp = GL11.glGetInteger(GL20.GL_CURRENT_PROGRAM);
        GL20.glUseProgram(GL20.glCreateProgram());
        GL20.glUseProgram(cp);
    }
}

public class HelloWorld {
    static Stage stage;

    public static class MainWindow extends ApplicationAdapter {
        @Override
        public void create () {
            stage = new Stage();
            Gdx.input.setInputProcessor(stage);

            stage.getRoot().addActor(new Label("test",
                    new Label.LabelStyle(
                            new BitmapFont(Gdx.files.internal("whitefont.fnt"), false),
                            Color.WHITE
                    )));
            stage.getRoot().addActor(new MyActor());
        }

        @Override
        public void render () {
            stage.act();
            stage.draw();
        }
    }

    public static void main(String[] argv) {
        Lwjgl3ApplicationConfiguration config = new Lwjgl3ApplicationConfiguration();
        new Lwjgl3Application(new MainWindow(), config);
    }
}