Normals.java

private static Texture generateNormalMapTexture(int width, int height, Tile[][] tiles) {
        pixmap = new Pixmap(width, height, Pixmap.Format.RGBA8888);
        texture = new Texture(width, height, Pixmap.Format.RGBA8888);

        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                Vector3 normal;

                // Ignore border pixels
                if(
                        x == 0 || y == 0 || x == width-1 || y == height-1) {
                    normal = new Vector3(1,1,1);
                    System.out.print(normal);
                    continue;
                }

                // Sample neighbors
                float hl = tiles[x-1][y].heightValue;
                float hr = tiles[x+1][y].heightValue;
                float ht = tiles[x][y+1].heightValue;
                float hb = tiles[x][y-1].heightValue;

                Vector3 dx = new Vector3(-1.0f, 0.0f, hr-hl);
                Vector3 dy = new Vector3(0.0f, -1.0f, ht - hb);


                // Compute sobel
                normal = dx.crs(dy);
                normal.z *= .5;
                normal = normal.nor();


                normal.add(1f).scl(0.5f);

                pixmap.drawPixel(x, y, Color.rgba8888(new Color(normal.x, normal.y, normal.z, 1)));
            }
        }


        PixmapIO.writePNG(Gdx.files.getFileHandle("normalmap.png", Files.FileType.Local), pixmap);
        texture.setWrap(Texture.TextureWrap.ClampToEdge, Texture.TextureWrap.ClampToEdge);
        texture.draw(pixmap, 0, 0);
        return texture;
    }