A DESCRIPTION OF THE PROBLEM :
Page https://openjfx.io/javadoc/20/javafx.graphics/javafx/scene/paint/PhongMaterial.html should be updated in relation of existence of DirectionalLight and SpotLight light sources. In the color computation pseudo-code the line:
                for each point light source i {
should be replaced with:
                for each directional, point, and spot light source i {
Also, "See Also:" list should be extended with DriectionalLight and SpotLight links.