public void setSpotOuterAngle(float spotOuterAngle) {
        if (spotOuterAngle < 0f || spotOuterAngle >= FastMath.HALF_PI) {
            throw new IllegalArgumentException("spot angle must be between 0 and pi/2");
        }
        this.spotOuterAngle = spotOuterAngle;
        computeAngleParameters();
    }
Sets the outer angle of the cone of influence.
<p>
Must be between 0 and pi/2.
<p>
This angle is the angle between the spot direction axis and the outer border of the cone of influence.
this should be greater than the inner angle or the result will be unexpected.

@param spotOuterAngle the desired angle (in radians, &ge;0, &le;Pi/2)
jme3-core/src/main/java/com/jme3/light/SpotLight.java