title: Mesh rendering issue libgdx
body: <p>I have a very simple program, that loads an wavefront obj file, rotate and displays it.
  The problem is that the program renders it with some issues (like missing triangles). I had a similar problem when I tried to render a Pyramid with a vertex buffer taken from NeHe's tutorial. So I don't know what cause this rendering issues. Can you help me? <img src="https://i.stack.imgur.com/Jy9mM.png" alt="Buggy Space Shuttle"></p>
  
  <pre><code>package com.jam.libgdx3DTest;
  
  import com.badlogic.gdx.Game;
  import com.badlogic.gdx.Gdx;
  import com.badlogic.gdx.graphics.*;
  import com.badlogic.gdx.graphics.g3d.loaders.obj.ObjLoader;
  
  import java.io.InputStream;
  
  public class Libgdx3DTest extends Game {
  
      private Mesh shuttleMesh;
      private Camera camera;
      private float rotateAngle;
  
      public void create() {
          if (shuttleMesh == null) {
              InputStream in = Gdx.files.internal("shuttle.obj").read();
              shuttleMesh = ObjLoader.loadObj(in, false);
          }
      }
  
      public void render() {
          Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
  
          Gdx.gl10.glMatrixMode(GL11.GL_MODELVIEW_MATRIX);
  
          Gdx.gl10.glLoadIdentity();
  
          camera.update();
          camera.apply(Gdx.gl10);
  
          rotateAngle += 0.5f;
          Gdx.gl10.glRotatef(rotateAngle, 0f, 1f, 0f);
          Gdx.gl10.glRotatef(-90f, 1f, 0f, 0f);
  
          shuttleMesh.render(GL11.GL_TRIANGLES);
      }
  
      public void resize(int width, int height) {
          float aspectRatio = (float) width / (float) height;
          camera = new PerspectiveCamera(67, 2f * aspectRatio, 2f);
          camera.translate(0f, 0f, 12f);
      }
  
      public void pause(){
      }
  
      public void resume(){
      }
  
      public void dispose() {
      }
  }
  </code></pre>