added isKeyDown Class for keyboard input

src/engine/Input.java

@@ -19,4 +19,8 @@ public class Input extends GLFWKeyCallback {
             if (glGetInteger(GL_POLYGON_MODE) == GL_FILL) glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
             else glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
     }
+    public static boolean isKeyDown(int keyCode) {
+		return glfwGetKey(Engine.getWindow(), keyCode) == 1;
+	} 
+    
 }