added more stuff and refactor

src/main/java/DirectionalLight.java

@@ -0,0 +1,16 @@
+import org.joml.Vector3f;
+
+public class DirectionalLight {
+    public Vector3f direction;
+    public Vector3f color;
+    public float intensity;
+
+    public DirectionalLight (
+            Vector3f direction,
+            Vector3f color,
+            float intensity) {
+        this.direction = direction;
+        this.color = color;
+        this.intensity = intensity;
+    }
+}