import com.badlogic.gdx.*;
import com.badlogic.gdx.Input.Keys;
import com.badlogic.gdx.backends.lwjgl.LwjglApplication;
import com.badlogic.gdx.graphics.*;
import com.badlogic.gdx.graphics.g2d.*;

public class BarebonesBatch extends ApplicationAdapter {
    PolygonSpriteBatch batch;
    Texture texture;
    PolygonRegion region;
    PolygonSprite sprite;

    public void create () {
        batch = new PolygonSpriteBatch();
        texture = new Texture(Gdx.files.internal("data/badlogic.jpg"));
        region = new PolygonRegion(new TextureRegion(texture), new float[] { 0, 0, 0, 100, 100, 100 }, new short[] { 0, 1, 2 });
        sprite = new PolygonSprite(region);
        sprite.setColor(0, 1, 0, 1);
    }

    public void render () {
        // Example:  calling getColor and modifying it causes a side-effect
        if (Gdx.input.isKeyJustPressed(Keys.SPACE)) {
          Color color = sprite.getColor();
          color.set(1, 0, 0, 1);  // only setColor should actually change the color
          //sprite.getVertexColor();  // fix: getVertexColor should be called inside setRegion
          sprite.setRegion(region);
        }
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        batch.begin();
        sprite.draw(batch);
        batch.end();
    }

    public static void main (String[] args) throws Exception {
        new LwjglApplication(new BarebonesBatch());
    }
}