public void renderPreview(ShapeRenderer shapeRenderer) {
        GL11.glEnable(GL11.GL_BLEND);
        GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_SRC_COLOR);
        shapeRenderer.begin();

        for (int face = 0; face < 6; ++face) {
            if (face == 0) {
                shapeRenderer.normal(0F, 1F, 0F);
            }

            if (face == 1) {
                shapeRenderer.normal(0F, -1F, 0F);
            }

            if (face == 2) {
                shapeRenderer.normal(0F, 0F, 1F);
            }

            if (face == 3) {
                shapeRenderer.normal(0F, 0F, -1F);
            }

            if (face == 4) {
                shapeRenderer.normal(1F, 0F, 0F);
            }

            if (face == 5) {
                shapeRenderer.normal(-1F, 0F, 0F);
            }

            renderInside(shapeRenderer, 0, 0, 0, face);
        }
        GL11.glDisable(GL11.GL_BLEND);
        shapeRenderer.end();
    }