Items, XP orbs, and projectiles - texture issue

Two-dimensional items (as entities) look as if they have a layer of invisible glass behind them, which can be seen when the bottom touches the shadow, and the edge can only be seen if you look right between the "glass". XP orbs have a similar issue, but the "glass" is colored the current color of the orb. Finally, projectiles (especially arrows) have their transparency replaced with white.