private DirectionalLight buildDirectionalLight(JsonObject obj) {
        //Get properties
        String name = obj.has("name") ? obj.get("name").getAsString() : "";

        float intensity = obj.has("intensity") ? obj.get("intensity").getAsFloat() : 1.0f;
        ColorRGBA color = obj.has("color") ? GltfUtils.getAsColor(obj, "color") : new ColorRGBA(ColorRGBA.White);
        color = lumensToColor(color, intensity);

        DirectionalLight directionalLight = new DirectionalLight();
        directionalLight.setName(name);
        directionalLight.setColor(color);
        directionalLight.setDirection(Vector3f.UNIT_Z.negate());

        return directionalLight;
    }
Build a directional light from gltf json.
@param obj The gltf json object for the directional light
@return A directional light representation of the gltf object
jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/LightsPunctualExtensionLoader.java