[1.7.10] Render on top of player

I want render an texture, of an shirt (One of 16 colours to denote the player team) on top of player but I want it to be the bottom most layer so I player is wearing some of Botania cosmetic baubles they are not covered. So I have subscribed RenderPlayerEvent, looking thorough some of the bit of event I thought this would be a good idea

```java

    event.setPhase(EventPriority.HIGHEST);

```

But I have no idea what to do overlay my texture on to the player, I have looked into Botania's source code, but it is scaring me openGL, I tell it is using call to openGL, but that my knowledge of openGL, I am hoping, I can do it with touching openGL.