public float getValue(int x, int y) {
        return hdata[y*width+x];
    }
Returns the height value for a given point.

MUST return the same value as getHeight(y*getWidth()+x)

@param x the X coordinate
@param y the Y coordinate
@return an arbitrary height looked up from the heightmap

@throws NullPointerException If isLoaded() is false
jme3-terrain/src/main/java/com/jme3/terrain/GeoMap.java