Grille de débogage pour libgdx

@Override
    public void create() {
        modelBatch = new ModelBatch();
        environment = new Environment();
        environment.set(new ColorAttribute(ColorAttribute.AmbientLight, 0.4f, 0.4f, 0.4f, 1f));
        environment.add(new DirectionalLight().set(0.8f, 0.8f, 0.8f, 10f, 10f, 20f));

        cam = new PerspectiveCamera(67, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
        cam.position.set(150f, -9f, 200f);
        cam.lookAt(0, 0, 0);
        cam.near = 1f;
        cam.far = 300f;
        cam.update();


        ModelBuilder modelBuilder = new ModelBuilder();
        model = modelBuilder.createSphere(120f, 120f, 120, 32, 32,
                new Material(ColorAttribute.createDiffuse(Color.GREEN)),
                VertexAttributes.Usage.Position | VertexAttributes.Usage.Normal);
        instance = new ModelInstance(model);
        instance.transform.set(new Vector3(100, 100, 0), new Quaternion());
    }

private void createaxes() {
        final float grid_min = -viewportwidth;
        final float grid_max = viewportwidth;
        final float grid_step = viewportwidth / 10;

        modelbuilder modelbuilder = new modelbuilder();
        modelbuilder.begin();
        meshpartbuilder builder = modelbuilder.part("grid", gl20.gl_lines, usage.position | usage.colorunpacked, new material());
        builder.setcolor(color.light_gray);
        for (float t = grid_min; t <= grid_max; t += grid_step) {
            builder.line(t, 0, grid_min, t, 0, grid_max);
            builder.line(grid_min, 0, t, grid_max, 0, t);
        }
        builder = modelbuilder.part("axes", gl20.gl_lines, usage.position | usage.colorunpacked, new material());
        builder.setcolor(color.red);
        builder.line(0, 0, 0, 100, 0, 0);
        builder.setcolor(color.green);
        builder.line(0, 0, 0, 0, 100, 0);
        builder.setcolor(color.blue);
        builder.line(0, 0, 0, 0, 0, 100);
        model axesmodel = modelbuilder.end();
        models.add(axesmodel);
        modelinstance instance = new modelinstance(axesmodel);
        instances.add(instance);
    }

grid = modelbuilder.createlinegrid(
   32, 32, 10.0f, 10.0f, 
    new material(colorattribute.creatediffuse(color.red)), 
    vertexattributes.usage.position | vertexattributes.usage.normal);

gridinstance = new modelinstance(grid);

modelBatch.render(gridInstance);