old:
tess.startDrawingQuads()
tess.addVertexWithUV(x, y, z, u, v)
tess.draw()

new:
tess.getWorldRenderer().begin(GL11.GL_QUADS, DefaultVertexFormats.POSITION_TEX)
tess.getWorldRenderer().pos(x, y, z).tex(u, v).endVertex()
...
tess.draw()