LibGDX SpriteBatch rendering error

Question

So earlier when I was testing my game everything went well, then I added some code. In my game I have states like PlayState or MenuState and now everything goes well, but when I try to switch the states in-game, the following error occurs:

Exception in thread "LWJGL Application" java.lang.NullPointerException
    at com.badlogic.gdx.graphics.g2d.SpriteBatch.flush(SpriteBatch.java:955)
    at com.badlogic.gdx.graphics.g2d.SpriteBatch.end(SpriteBatch.java:176)
    at com.platformer.Entities.Player.draw(Player.java:191)
    at com.platformer.gamestates.PlayState.draw(PlayState.java:102)
    at com.platformer.managers.GameStateManager.draw(GameStateManager.java:44)
    at com.platformer.game.Game.render(Game.java:55)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:214)
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:120)

It says that the problem is in my Player class, so here is the code:

package com.platformer.Entities;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import static com.platformer.managers.B2DVars.PPM;

import com.badlogic.gdx.graphics.g2d.TextureAtlas.AtlasRegion;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;
import com.platformer.game.Game;
import com.platformer.managers.Animation;
import com.platformer.managers.B2DVars;
import com.platformer.managers.GameContacts;

import java.util.Random;

/**
 * Created by Oliverss on 23/04/2015.
 */
public class Player extends Entities{

    public static boolean DebugOn=false;
    public boolean shouldPlay=false;
    public boolean shouldMenu=false;

    public static final int LEFT = 0;
    public static final int RIGHT = 1;
    public int direction=1;

    float BPF=255f;
    int canJump=0;
    float weaponY;

    public static int shade=100;
    public static int coatColor;

    Controller controller;
    Weapons weapon;

    Random random=new Random();

    float[][] skinShades={
            {210/BPF,180/BPF,140/BPF},  //tan
            {139/BPF,69/BPF,19/BPF},    //saddle-brown
            {160/BPF,82/BPF,45/BPF},    //sienna
            {255/BPF,235/BPF,205/BPF},  //blanched almond
            {255/BPF,228/BPF,196/BPF},  //bisque
    };

    float[][] coatColors={
            {64/BPF,64/BPF,64/BPF},  //dark-gray
            {102/BPF,102/BPF,0/BPF},  //dark-green
            {47/BPF,79/BPF,79/BPF},   //dark-slate-gray
            {165/BPF,42/BPF,42/BPF},    //brown
    };

    public Player(World world,float x,float y){

        this.x=x;
        this.y=y;
        speed=1.5f;

        if(shade==100){
            shade=random.nextInt(skinShades.length);
            coatColor=random.nextInt(coatColors.length);
            System.out.println("*Generating*");
            System.out.println("shade "+shade);
            System.out.println("coat "+coatColor);
        }

        controller=new Controller();
        weapon=new Weapons("pistol");

        AtlasRegion region=Game.atlas.findRegion("playerskin");
        TextureRegion[] sprites=region.split(32,32)[0];
        skinAnimation=new Animation(sprites,1/12f);

        region=Game.atlas.findRegion("playercoat");
        sprites=region.split(32,32)[0];
        coatAnimation=new Animation(sprites,1/12f);

        region=Game.atlas.findRegion("playerskinjump");
        sprites=region.split(32,32)[0];
        skinJumpAnimation=new Animation(sprites,1/12f);

        region=Game.atlas.findRegion("playercoatjump");
        sprites=region.split(32,32)[0];
        coatJumpAnimation=new Animation(sprites,1/12f);

        skin=new Sprite();
        skin.setSize(32/PPM,32/PPM);

        coat=new Sprite();
        coat.setSize(32/PPM,32/PPM);

        bdef=new BodyDef();
        bdef.position.set(x/PPM,y/PPM);
        bdef.type=BodyType.DynamicBody;
        body=world.createBody(bdef);

        PolygonShape shape=new PolygonShape();
        shape.setAsBox(9/PPM,15/PPM);

        fdef=new FixtureDef();
        fdef.shape=shape;
        fdef.filter.categoryBits=B2DVars.BIT_PLAYER;
        fdef.filter.maskBits=B2DVars.BIT_BLOCK|B2DVars.BIT_HOUSE;
        body.createFixture(fdef).setUserData("player");

        //create sensor
        shape.setAsBox(7/PPM,6/PPM,new Vector2(0,-16/PPM),0);
        fdef.shape=shape;
        fdef.filter.categoryBits=B2DVars.BIT_PLAYER;
        fdef.filter.maskBits=B2DVars.BIT_BLOCK;
        fdef.isSensor=true;
        body.createFixture(fdef).setUserData("player_sensor");

    }

    public void update(float dt,GameContacts gameContacts){

        handleInput(dt,gameContacts);

        skin.setPosition(body.getPosition().x-(16/PPM),body.getPosition().y-(17/PPM));
        coat.setPosition(body.getPosition().x-(16/PPM),body.getPosition().y-(17/PPM));

        switch (movementState){
            case 0:{
                coatAnimation.setCurrentFrame(0);
                skinAnimation.setCurrentFrame(0);
                coatJumpAnimation.setCurrentFrame(0);
                skinJumpAnimation.setCurrentFrame(0);
                coat.setRegion(coatAnimation.getFrame());
                skin.setRegion(skinAnimation.getFrame());
                break;
            }
            case 1:{
                coatAnimation.update(dt);
                skinAnimation.update(dt);
                coat.setRegion(coatAnimation.getFrame());
                skin.setRegion(skinAnimation.getFrame());
                break;
            }
            case 2:{
                coatAnimation.update(dt);
                skinAnimation.update(dt);
                coat.setRegion(coatAnimation.getFrame());
                skin.setRegion(skinAnimation.getFrame());
                break;
            }
            case 3:{
                coatAnimation.setCurrentFrame(0);
                skinAnimation.setCurrentFrame(0);
                coat.setRegion(coatJumpAnimation.getFrame());
                skin.setRegion(skinJumpAnimation.getFrame());
                break;
            }

        }

        y=coat.getY();
        x=coat.getX();
        weaponY=y;

        if(!gameContacts.isPlayerOnGround()){
            coatJumpAnimation.setCurrentFrame(1);
            skinJumpAnimation.setCurrentFrame(1);
            coat.setRegion(coatJumpAnimation.getFrame());
            skin.setRegion(skinJumpAnimation.getFrame());
            weaponY+=4/PPM;
        }

        weapon.update(x,weaponY,direction,coatAnimation.getCurrentFrame());

    }

    public void draw(SpriteBatch batch){

        if(direction==LEFT)flip();

        batch.begin();
        skin.draw(batch);
        coat.draw(batch);
        batch.end();

        weapon.draw(batch);

        controller.debug(DebugOn);
        controller.draw();

    }

    public void flip(){

        skin.flip(true,false);
        coat.flip(true,false);

    }

    public void handleInput(float dt,GameContacts gameContacts){

        //movement
        if(controller.leftDown||Gdx.input.isKeyPressed(Input.Keys.LEFT))movementState=1;
        if(controller.rightDown||Gdx.input.isKeyPressed(Input.Keys.RIGHT))movementState=2;
        if(!controller.leftDown&&!controller.rightDown&&!Gdx.input.isKeyPressed(Input.Keys.LEFT)&&!Gdx.input.isKeyPressed(Input.Keys.RIGHT))movementState=0;

        Vector2 vec=body.getLinearVelocity();
        force=0;

        switch (movementState){
            case 1:if(vec.x>-speed)force=-50;direction=LEFT;break;
            case 2:if(vec.x<speed)force=50;direction=RIGHT;break;
            case 0:force=vec.x*-10;break;
        }

        body.applyForceToCenter(new Vector2(force,0),true);

        if((controller.jumpDown||Gdx.input.isKeyPressed(Input.Keys.UP))&&gameContacts.isPlayerOnGround()&&canJump>50){
            body.applyForceToCenter(0,300,true);
            canJump=0;
        }
        if(canJump>51)canJump=51;
        canJump++;
        if(canJump<52)movementState=3;

        if(controller.attackdown&&gameContacts.isOnHouse()){
            shouldPlay=true;
        }

        if(Gdx.input.isKeyJustPressed(Input.Keys.C)){
            shade=random.nextInt(skinShades.length);
            coatColor=random.nextInt(coatColors.length);
            System.out.println("shade "+shade);
            System.out.println("coat "+coatColor);
        }

        skin.setColor(skinShades[shade][0],skinShades[shade][1],skinShades[shade][2],1);
        coat.setColor(coatColors[coatColor][0],coatColors[coatColor][1],coatColors[coatColor][2],1);

        //debug
        if(controller.attackdown&&(Gdx.input.isKeyJustPressed(Input.Keys.VOLUME_DOWN)||Gdx.input.isKeyJustPressed(Input.Keys.VOLUME_UP)||Gdx.input.isKeyJustPressed(Input.Keys.CONTROL_LEFT))){if(DebugOn){DebugOn=false;System.out.println("off");}else{DebugOn=true;System.out.println("on");}}
        //debug
        if(controller.jumpDown&&(Gdx.input.isKeyJustPressed(Input.Keys.VOLUME_DOWN)||Gdx.input.isKeyJustPressed(Input.Keys.VOLUME_UP)||Gdx.input.isKeyJustPressed(Input.Keys.CONTROL_LEFT))){shouldMenu=true;}
    }

    @Override
    public void dispose(){
        skin.getTexture().dispose();
        coat.getTexture().dispose();
        weapon.dispose();
    }

    public float getx(){return x;}
    public float gety(){return y;}

}

What is the problem here?

Answer 1

Are you sure that skin and coat have a texture applied when being drawn?

Your error message suggests that the problem is here:

batch.begin();
skin.draw(batch);
coat.draw(batch);
batch.end();

The only thing I can think of would be if the state was messed up and they didn't have a texture to draw.

Answer 2

What version of libgdx are you using?

If it's the same as mine (1.5.4), then the issue is on this line...

lastTexture.bind();

So it looks like you've lost some textures during state changes.

Answer 3

This might help if someone is still facing this issue. Actually, this error occurs when batch is going to replace the last drawn texture with the new one. So, in fact, the texture is missed in the last draw statement, not the statement on which the exception actually occurs.

For example, I have these 2 lines in render method:

  batch.draw(backgroundImage, 0, 0,width, height);
  batch.draw(mainCharacter, 0, 0,width, height);

I was facing exception while drawing main character, but at the end I figure out that I forgot to assign the texture to the background region.