Shader-problem

package com.rojarstudios.prisma.screens;

import org.mini2Dx.core.game.GameContainer;
import org.mini2Dx.core.graphics.Graphics;
import org.mini2Dx.core.screen.GameScreen;
import org.mini2Dx.core.screen.ScreenManager;
import org.mini2Dx.core.screen.Transition;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.glutils.ShaderProgram;
import com.rojarstudios.prisma.PrismaGame;
import com.rojarstudios.prisma.GUI.GUI;
import com.rojarstudios.prisma.saveSystem.HeroColors;
import com.rojarstudios.prisma.world.WorldRender;

public class PlayScreen implements GameScreen {

    public static int ID = 0;
    PrismaGame game;
    //GUI gui = new GUI();

    WorldRender worldRender;

    ShaderProgram shader;
    SpriteBatch batch;
    Texture tex;

    public PlayScreen(PrismaGame game, int ID) {
        PlayScreen.ID = ID;
        this.game = game;
    }

    @Override
    public int getId() {
        return ID;
    }

    @Override
    public void initialise(GameContainer gc) {
        worldRender = new WorldRender();
        worldRender.init(gc);
        HeroColors.init(gc);
        //gui.initialise(gc);

        ShaderProgram.pedantic = false;
        shader = new ShaderProgram(Gdx.files.internal("assets/shaders/vignette.vsh"), Gdx.files.internal("assets/shaders/vignette.fsh"));
        if(!shader.isCompiled()) {
            System.out.println(shader.getLog());
        }

        tex = new Texture(Gdx.files.internal("assets/GUI/level_tab.png"));

        batch = new SpriteBatch(1000, shader);
        batch.setShader(shader);

    }

    @Override
    public void interpolate(GameContainer gc, float alpha) {
        worldRender.interpolate(gc, alpha);
    }

    @Override
    public void postTransitionIn(Transition arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void postTransitionOut(Transition arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void preTransitionIn(Transition arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void preTransitionOut(Transition arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void render(GameContainer gc, Graphics g) {
        batch.begin();
        batch.draw(tex, 0, 0);
        batch.end();

        worldRender.render(gc, g);
        HeroColors.render(gc, g);
        //gui.render(gc, g);
    }

    int timer = 0;
    @Override
    public void update(GameContainer gc,
            ScreenManager<? extends GameScreen> screenManager, float delta) {
        worldRender.update(gc, screenManager, delta);
        HeroColors color = new HeroColors();
        //gui.update(gc, screenManager, delta);
        timer++;
        if(timer >= 75) {
            System.out.println("FPS:" + Gdx.graphics.getFramesPerSecond());
            timer = 0;
        }
    }

}