public void setLambda(float lambda) {
        this.lambda = lambda;
    }
Adjusts the partition of the shadow extend into shadow maps.
Lambda is usually between 0 and 1.
A low value gives a more linear repartition,
resulting in consistent shadow quality over the extend,
but near shadows could look very jagged.
A high value gives a more logarithmic repartition,
resulting in high quality for near shadows,
but quality decreases rapidly with distance.
The default value is 0.65 (the theoretical optimum).

@param lambda the lambda value.
jme3-core/src/main/java/com/jme3/shadow/PssmShadowRenderer.java