public void set(int i, float x, float y, float z) {
        center = null;
        normal = null;

        switch (i) {
            case 0:
                pointA.set(x, y, z);
                break;
            case 1:
                pointB.set(x, y, z);
                break;
            case 2:
                pointC.set(x, y, z);
                break;
        }
    }
Alters the location of the indexed vertex and deletes the stored centroid
and normal.

@param i the index of the vertex to alter (0, 1, or 2)
@param x the desired X coordinate
@param y the desired Y coordinate
@param z the desired Z coordinate
jme3-core/src/main/java/com/jme3/math/Triangle.java