You have to adjust your setupMap() method to assign UV coordinates correctly.
/**
* adds plane to the specified object
*
* @param target actor to update
* @param c1 4 coordinate points, CCW
* @param c2
* @param c3
* @param c4
*/
private static void addPlane(Object3D target, SimpleVector c1, SimpleVector c2, SimpleVector c3,
SimpleVector c4, float cellSize) {
SimpleVector xVct = new SimpleVector(c1.calcSub(c2));
SimpleVector yVct = new SimpleVector(c3.calcSub(c2));
float x = xVct.length();
float y = yVct.length();
float xCoeff = x / cellSize;
float yCoeff = y / cellSize;
target.addTriangle(c2, 0, 0, c3, 0, yCoeff, c1, xCoeff, 0, 0, 0);
target.addTriangle(c3, 0, yCoeff, c4, xCoeff, yCoeff, c1, xCoeff, 0, 0, 0);
}