NO! cut it up like normal triangles, then select your brushes and move it to allign with the texture but remember not to go out of that border. then if you don't have enough brushes, just select 1 brush and move it to allign to the texture but there will be a gap between that triangle and the one next to it, just copy that brush and then fill that empty space up, keep on doing that to make the triangles alligned with the texture.
If you don't understand I'll make a small tutorial using pics or something.