A lot of comments, assets update

.classpath

@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" output="target/classes" path="src/main/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry excluding="**" kind="src" output="target/classes" path="src/main/resources">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="test" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="target/generated-sources/annotations">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="ignore_optional_problems" value="true"/>
+			<attribute name="m2e-apt" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" output="target/test-classes" path="target/generated-test-sources/test-annotations">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="ignore_optional_problems" value="true"/>
+			<attribute name="m2e-apt" value="true"/>
+			<attribute name="test" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="output" path="target/classes"/>
+</classpath>

.project

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>DanmakuProject</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.m2e.core.maven2Builder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.m2e.core.maven2Nature</nature>
+	</natures>
+	<filteredResources>
+		<filter>
+			<id>1640019058211</id>
+			<name></name>
+			<type>30</type>
+			<matcher>
+				<id>org.eclipse.core.resources.regexFilterMatcher</id>
+				<arguments>node_modules|.git|__CREATED_BY_JAVA_LANGUAGE_SERVER__</arguments>
+			</matcher>
+		</filter>
+	</filteredResources>
+</projectDescription>

.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,4 @@
+eclipse.preferences.version=1
+encoding//src/main/java=UTF-8
+encoding//src/main/resources=UTF-8
+encoding/<project>=UTF-8

.settings/org.eclipse.jdt.apt.core.prefs

@@ -0,0 +1,2 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.apt.aptEnabled=false

.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,9 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
+org.eclipse.jdt.core.compiler.compliance=1.8
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.forbiddenReference=warning
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=ignore
+org.eclipse.jdt.core.compiler.processAnnotations=disabled
+org.eclipse.jdt.core.compiler.release=disabled
+org.eclipse.jdt.core.compiler.source=1.8

.settings/org.eclipse.m2e.core.prefs

@@ -0,0 +1,4 @@
+activeProfiles=
+eclipse.preferences.version=1
+resolveWorkspaceProjects=true
+version=1

README.md

@@ -0,0 +1,17 @@
+# DanmakuProject
+
+This is made for a school project. It uses SDL2 under Java using JNA library.
+The main bindings are from libjsdl which is an attempt to create an interface for SDL2 using JNA
+but it lacks documentation and demonstration (still a great project). Some SDL2_mixer bindings are
+also created using JNA, which is not part of the libjsdl. (see Audio.java)
+
+I hope this proves to be a good demonstration for using libjsdl and JNA.
+
+## Credits:
+* Furkan Mudanyalı (Code, planning, execution etc.)
+* graphLoom, (Music, assets)
+
+### Further Credits:
+* libjsdl contributors (especially shinedeveloper for a loot of bindings)
+* SDL2 contributors
+* SDL2_mixer contributors

src/main/java/com/fmudanyali/Audio.java

@@ -33,7 +33,7 @@ import javax.sound.sampled.AudioSystem;
 /**
  * <h3>Audio Class</h3>
  * 
- * This class is a native wrapper for SDL2_Mixer,
+ * This class is a native JNA wrapper for SDL2_Mixer,
  * it also contains some additional methods
  * 
  * @author Furkan Mudanyali
@@ -127,14 +127,21 @@ public class Audio {
     public static int Mix_PlayChannel(int channel, Pointer chunk, int loops){
         return Mix_PlayChannelTimed(channel, chunk, loops, -1);
     }
+
     // Methods
 
     /**
+     * Returns WAV music length in milliseconds.
+     * 
+     * <p>
+     * 
      * Credits to mdma from stackoverflow
+     * <p>
      * https://stackoverflow.com/a/3009973
      * 
      * @param filepath WAV file path
-     * @return length in milliseconds
+     * @return length in milliseconds, -1 if can't
+     * open file.
      */
     public static long getMusicLengthInMilliseconds(String filepath){
         try {

src/main/java/com/fmudanyali/FileLoader.java

@@ -21,10 +21,25 @@ import java.io.File;
 import java.util.Objects;
 
 /**
- * @param fileName filename to get path of
- * @return path to the asset in the assets folder.
+ * <h3>File Loader Class</h3>
+ * 
+ * A class that contains static methods for file path
+ * operations for SDL2. Since SDL2 cannot access the
+ * virtual filesystem inside the .jar package, SDL2 files
+ * must be kept in a seperate folder along with the .jar.
+ * 
+ * @author Furkan Mudanyali
+ * @version 1.0.0
+ * @since 2021-12-01
  */
 public class FileLoader {
+    /**
+     * Returns absolute path to the file from the assets folder.
+     * 
+     * @param fileName filename to get path of
+     * @return path to the asset in the assets folder,
+     * null on any kind of I/O error.
+     */
     public static String getFilePath(String fileName){
         try{
             String protocol = FileLoader.class.getResource("").getProtocol();
@@ -35,7 +50,7 @@ public class FileLoader {
             }
             return System.getProperty("user.dir") + "/assets/" + fileName;
         } catch (Exception e){
-            return "could not get filepath";
+            return null;
         }
     }
 }

src/main/java/com/fmudanyali/Keyboard.java

@@ -20,13 +20,28 @@ package com.fmudanyali;
 import static org.libsdl.api.keyboard.SdlKeyboard.*;
 import com.sun.jna.ptr.ByteByReference;
 
+/**
+ * <h3>Keyboard Class</h3>
+ * 
+ * A class to simplify keyboard functions.
+ * 
+ * @author Furkan Mudanyali
+ * @version 1.0.0
+ * @since 2021-12-01
+ */
 public class Keyboard {
+    // Basically array pointer
     public static ByteByReference keyboard = new ByteByReference();
 
     public static void getKeyboardState(){
         keyboard = SDL_GetKeyboardState(null);
     }
-
+    /**
+     * Checks if given index of the keyboard array is true or not.
+     * 
+     * @param key Index of the key in the keyboard array.
+     * @return true if key is pressed, false if not.
+     */
     public static boolean getKeyState(int key){
         return keyboard.getPointer().getByte(key) == 1;
     }

src/main/java/com/fmudanyali/Main.java

@@ -21,23 +21,49 @@ import com.fmudanyali.scenes.*;
 import java.util.Stack;
 import org.libsdl.api.event.events.SDL_Event;
 
+/**
+ * <h3>Main Class</h3>
+ * This is the starting point of the application.
+ * 
+ * @author Furkan Mudanyali
+ * @version 1.0.0
+ * @since 2021-12-01
+ */
 public class Main {
     public static SDL_Event e = new SDL_Event();
     public static boolean exit = false;
     public static Stack<Scene> scenes = new Stack<>();
     public static void main(String[] args) throws Exception{
+        /*
+        Restart JVM if on macOS and it hasn't been launched
+        with -XStartOnFirstThread arg. Needed for SDL to be
+        able to create a window and show it on macOS as macOS
+        ignores windows that are not opened by the first thread
+        of the application for safety measures. Took me days
+        to track the bug.
+        */ 
         if (RestartJVM.restartJVM()) {
             return;
         }
 
+        // Open audio device with basic defaults.
         Audio.Mix_OpenAudio(44100, Audio.MIX_DEFAULT_FORMAT, 2, 2048);
+        // Push main menu to the scenes stack.
         scenes.push(new MainMenu());
 
+        // Each loop means a frame of the game.
         while(!scenes.empty() && !exit){
+            // Calculate delta time, between last frame
+            // and this frame.
             Time.Tick();
             Keyboard.getKeyboardState();
+            // Call the loop function of the scene on the
+            // top of the scenes stack.
             scenes.peek().loop();
         }
+        // Exit is set to true manually to make sure the existing threads
+        // are stopped, not really necessary as System.exit should close
+        // those lingering threads but better be safe than sorry.
         exit = true;
         System.exit(0);
     }

src/main/java/com/fmudanyali/Render.java

@@ -33,24 +33,50 @@ import static org.libsdl.api.hints.SdlHintsConst.*;
 import static org.libsdl.api.hints.SdlHints.*;
 import static org.libsdl.api.render.SdlRender.SDL_RenderSetLogicalSize;
 
+/**
+ * <h3>Render Class</h3>
+ * This class contains and initializes the SDL_Window and SDL_Renderer pointers,
+ * it also has a method to create a continuous background from given texture.
+ * 
+ * @author Furkan Mudanyali
+ * @version 0.2.0
+ * @since 2021-12-01
+ */
 public class Render {
     public static SDL_Window window;
     public static SDL_Renderer renderer;
     public static int bgw, bgh;
 
+    // Initialize SDL_Window and SDL_Renderer
     static {
+        // Create window
         window = SDL_CreateWindow("DanmakuProject SDL2",
             SDL_WINDOWPOS_CENTERED(), SDL_WINDOWPOS_CENTERED(),
             WIDTH, HEIGHT, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL);
 
+        // Hints for the renderer
         SDL_SetHint(SDL_HINT_RENDER_DRIVER, "opengl");
         SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "0");
 
+        // Create renderer
         renderer = 
-            SDL_CreateRenderer(Render.window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
+            SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
 
+        // Make content scale according to the window size while maintaining the aspect ratio.
         SDL_RenderSetLogicalSize(renderer, Screen.WIDTH, Screen.HEIGHT);
     }
+
+    /**
+     * Creates a new row x col texture
+     * from the given texture by stitching
+     * it together.
+     * 
+     * @param renderer Renderer to be used
+     * @param texture Texture to be repeated
+     * @param cols How many columns of the texture
+     * @param rows How many rows of the texture
+     * @return
+     */
     public static SDL_Texture createBackgroundFromTexture(
         SDL_Renderer renderer, SDL_Texture texture, int cols, int rows
     ){

src/main/java/com/fmudanyali/RestartJVM.java

@@ -25,10 +25,22 @@ import java.io.InputStreamReader;
 import java.io.BufferedReader;
 
 /**
- * Credits to kappa From
+ * <h3>RestartJVM Class</h3>
+ * 
+ * Has a single function that restarts JVM on macOS
+ * if JVM is not launched with -XstartOnFirstThread arg
+ * and launches it with it.
+ * 
+ * <p>
+ * 
+ * Credits to kappa from jvm-gaming.org
+ * <p>
  * https://jvm-gaming.org/t/starting-jvm-on-mac-with-xstartonfirstthread-programmatically/57547
+ * 
+ * @author kappa
+ * @version 1.0.0
+ * @since 2016-08-26
  */
-
 public class RestartJVM {
 	public static boolean restartJVM() {
 		

src/main/java/com/fmudanyali/Screen.java

@@ -27,6 +27,16 @@ import com.fmudanyali.characters.Player;
 
 import static org.libsdl.api.render.SdlRender.*;
 
+/**
+ * <h3>Screen Class</h3>
+ * 
+ * This class contains information about the game screen
+ * It also has a method to set its background texture, and scroll it.
+ * 
+ * @author Furkan Mudanyali
+ * @version 0.2.0
+ * @since 2021-12-08
+ */
 public class Screen {
     public static final int WIDTH = 960;
     public static final int HEIGHT = 540;
@@ -38,6 +48,7 @@ public class Screen {
     public static SDL_Texture tile, background, wallpaper;
     public static SDL_Surface tempSurface;
     
+    // Calculate positions and load wallpaper image.
     static {
         canvas.x = 12;
         canvas.y = 0;
@@ -54,6 +65,10 @@ public class Screen {
         tempSurface = null;
     }
 
+    /**
+     * Loads the given filepath to the background.
+     * @param filename file path of the image.
+     */
     public static void makeBackground(String filename){
         // Load tile
         tempSurface = SDL_LoadBMP(FileLoader.getFilePath(filename));
@@ -64,6 +79,12 @@ public class Screen {
         background = Render.createBackgroundFromTexture(Render.renderer, tile, 1, 2);
     }
 
+    /**
+     * Scrolls the background vertically and horizontally.
+     * Horizontal scroll is based on the player position to 
+     * create a parallax effect.
+     * @param player
+     */
     public static void scroll(Player player){
         canvas.y = Math.floorMod(canvas.y - (int)(Time.deltaTime * 0.1), Render.bgh - canvas.h);
         canvas.x = (int)(12 + (player.position.x - 464)/13);

src/main/java/com/fmudanyali/Time.java

@@ -19,6 +19,16 @@ package com.fmudanyali;
 
 import static org.libsdl.api.timer.SdlTimer.*;
 
+/**
+ * <h3>Time Class</h3>
+ * 
+ * Calculates the time difference between this frame
+ * and last frame, deltatime.
+ * 
+ * @author Furkan Mudanyali
+ * @version 1.0.0
+ * @since 2021-12-03
+ */
 public class Time {
     public static int lastTime = 0;
     public static int currentTime = 0;

src/main/java/com/fmudanyali/bullets/PlayerBullet.java

@@ -28,13 +28,27 @@ import org.libsdl.api.surface.SDL_Surface;
 import static org.libsdl.api.surface.SdlSurface.*;
 import static org.libsdl.api.render.SdlRender.*;
 
+/**
+ * <h3>PlayerBullet Class</h3>
+ * 
+ * This class is for player made projectiles
+ * that advance forward in the screen and explode
+ * on enemy contact (to be implemented).
+ * 
+ * @author Furkan Mudanyali
+ * @version 0.4.0
+ * @since 2021-12-22
+ */
 public class PlayerBullet {
+    // Load the texture
     public static SDL_Surface tempSurface = SDL_LoadBMP(FileLoader.getFilePath("player/bullet.bmp"));
     public static SDL_Texture texture = SDL_CreateTextureFromSurface(Render.renderer, tempSurface);
     public SDL_Rect position = new SDL_Rect();
     public int width = 5;
     public int height = 12;
 
+    // Set the bullet position relative to the player position and given
+    // offsets.
     public PlayerBullet(SDL_Rect playerPos, int xOffset, int yOffset){
         position.w = width;
         position.h = height;
@@ -42,6 +56,9 @@ public class PlayerBullet {
         position.y = playerPos.y - 6 - 3 - yOffset;
     }
 
+    /**
+     * Advances the bullet on the screen.
+     */
     public void fly(){
         position.y = position.y - (int)(Time.deltaTime * 0.5);
     }

src/main/java/com/fmudanyali/characters/Character.java

@@ -21,6 +21,16 @@ import org.libsdl.api.rect.SDL_Rect;
 import org.libsdl.api.render.SDL_Texture;
 import org.libsdl.api.surface.SDL_Surface;
 
+/**
+ * <h3>Character Superclass</h3>
+ * 
+ * This class provides essentials that a character
+ * should require.
+ * 
+ * @author Furkan Mudanyali
+ * @version 1.0.0
+ * @since 2021-12-08
+ */
 public class Character {
     public SDL_Rect position = new SDL_Rect();
     public SDL_Texture texture = new SDL_Texture();

src/main/java/com/fmudanyali/characters/Enemy.java

@@ -18,5 +18,5 @@
 package com.fmudanyali.characters;
 
 public class Enemy extends Character {
-    
+    // TODO: Implement
 }

src/main/java/com/fmudanyali/characters/Player.java

@@ -32,7 +32,19 @@ import static org.libsdl.api.surface.SdlSurface.*;
 import static org.libsdl.api.render.SdlRender.*;
 import static org.libsdl.api.scancode.SDL_Scancode.*;
 
+/**
+ * <h3>Player Class</h3>
+ * 
+ * This class extends on the character class and has all the
+ * bells and whistles such as handling movement, shooting bullets,
+ * animated sprites etc.
+ * 
+ * @author Furkan Mudanyali
+ * @version 0.9.0
+ * @since 2021-12-08
+ */
 public class Player extends Character {
+    // Variables
     public int lives;
     public double speed;
     public SDL_Texture propeller;
@@ -40,14 +52,16 @@ public class Player extends Character {
     public int frame = 0;
     public int roll = 0;
     public int cooldown = 0;
-
+    // New position rectangles for additional parts
     public SDL_Rect propellerPos = new SDL_Rect();
     public SDL_Rect shooterPos = new SDL_Rect();
-
+    // These rectangles are used for shifting 
+    // sprite animation.
     public SDL_Rect shipFrame = new SDL_Rect();
     public SDL_Rect propellerFrame = new SDL_Rect();
     public SDL_Rect shooterFrame = new SDL_Rect();
     
+    // Load the textures and set the positions.
     public Player(){
         lives = 3;
         tempSurface = SDL_LoadBMP(FileLoader.getFilePath("player/ship.bmp"));
@@ -167,7 +181,8 @@ public class Player extends Character {
                 propellerFrame.x = 10;
                 break;
         }
-
+        // Not a switch as DeltaTime does not provide
+        // linear increase.
         if(roll > 0){
             shipFrame.x = shipFrame.y = 0;
         } if(roll > 15){
@@ -178,17 +193,23 @@ public class Player extends Character {
         } if(roll > 45){
             shipFrame.x = 32;
         }
-
+        // Frame is kept in 600 instead of 60
+        // to be accurate with the varying framerate
+        // animations.
         frame = (frame+10)%600;
     }
 
+    /**
+     * Changes positions depending on the keyboard state.
+     */
     public void movement(){
+        // If shift is pressed, slow down the player.
         if(Keyboard.getKeyState(SDL_SCANCODE_LSHIFT)){
             speed = 1.5;
         }else{
             speed = 2;
         }
-
+        // Bunch of mathematical mumbo jumbo.
         if(Keyboard.getKeyState(SDL_SCANCODE_A) | Keyboard.getKeyState(SDL_SCANCODE_LEFT)){
             position.x = Math.max(position.x - (int)(speed * Time.deltaTime * 0.1), Screen.canvasPos.x - 5);
             shooterPos.x = Math.max(shooterPos.x - (int)(speed * Time.deltaTime * 0.1), Screen.canvasPos.x + 16 - 4 - 5);
@@ -227,7 +248,8 @@ public class Player extends Character {
             Game.playerBullets.add(new PlayerBullet(position, 17, 0));
             Game.playerBullets.add(new PlayerBullet(position, 21, 6));
             Game.playerBullets.add(new PlayerBullet(position, 25, 9));
-            cooldown = 1;
+            // Cooldown is used to prevent overshooting.
+            cooldown = 3;
         }
         cooldown = Math.max(cooldown -1, 0);
     }

src/main/java/com/fmudanyali/scenes/Game.java

@@ -33,51 +33,85 @@ import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 
+/**
+ * <h3>Game Class</h3>
+ * 
+ * This class extends on the Scene class and is mainly
+ * the core of the game.
+ * 
+ * @author Furkan Mudanyali
+ * @version 0.1.0
+ * @since 2021-12-04
+ */
 public class Game extends Scene {
+    // Variables
     public static boolean escPressed = false;
     int kek = 0;
     private Player player = new Player();
+    // Keeping track of the shots fired
     public static List<PlayerBullet> playerBullets = new ArrayList<>();
+    // Thread for bg music
     private static Thread thread;
+    // Create a runnable for the thread
     private static Runnable runnable = new Runnable() {
         public void run(){
             try {
                 Mix_PlayMusic(Mix_LoadMUS(FileLoader.getFilePath("80-search-intro.wav")), 1);
+                // Sleeping for the duration of the intro instead of checking if it stopped on a 
+                // loop saves a loooot of clock cycles.
                 Thread.sleep(getMusicLengthInMilliseconds(FileLoader.getFilePath("80-search-intro.wav")));
                 Mix_PlayMusic(Mix_LoadMUS(FileLoader.getFilePath("80-search-loop.wav")), -1);
+                // Kill self because the last music will loop forever
                 Thread.currentThread().interrupt();
                 return;
             } catch(Exception e){
-                // Will throw sleep interrupted, which is what we want.
+                // Will throw sleep interrupted, which is exactly what we want.
             }
         }
     };
 
     public Game(){
+        // Create the looping background
         Screen.makeBackground("shmap.bmp");
+        // Set music volume to max
         Mix_VolumeMusic(128);
+        // Try reading thread state, will throw exception for
+        // the first time as the thread will not be initialized
+        // at that time, which is perfectly expected.
         try {
+            // Interrupt the thread if its running, this is needed
+            // to keep only one thread alive at a time because if
+            // the game is immediately quitted and a new game started,
+            // the music will not get confused.
             if(thread.getState() != Thread.State.TERMINATED){
                 thread.interrupt();
             }
         } catch (Exception e){
-            //
+            // Do nothing as I expect this behavior.
         }
+        // Overwrite the the TERMINATED (or not initialized)
+        // thread with a new thread with our runnable.
         thread = new Thread(runnable);
+        // Start the thread.
         thread.start();
         
     }
 
     @Override
     public void loop(){
+        // Handle events first
         while(SDL_PollEvent(Main.e) != 0){
             switch(Main.e.type){
+                // If close button on the window is pressed.
                 case SDL_QUIT:
                     Main.exit = true;
                     break;
+                // If a key is pressed
                 case SDL_KEYDOWN:
                     switch(Main.e.key.keysym.sym){
+                        // If ESC is pressed, push pause menu to the scenes stack
                         case SDLK_ESCAPE:
+                            // Needed to execute it only once per conventional key press
                             if(!escPressed){
                                 Main.scenes.push(new PauseMenu());
                                 Mix_VolumeMusic(30);
@@ -86,6 +120,7 @@ public class Game extends Scene {
                             break;
                     }
                     break;
+                // If a key is released
                 case SDL_KEYUP:
                     switch(Main.e.key.keysym.sym){
                         case SDLK_ESCAPE:
@@ -96,27 +131,31 @@ public class Game extends Scene {
             }
         }
 
+        // Do player movement thing and scroll the screen
         player.movement();
         Screen.scroll(player);
-
+        // Copying stuff to the renderer
         SDL_RenderClear(renderer);
         SDL_RenderCopy(renderer, Screen.wallpaper, null, null);
         SDL_RenderCopy(renderer, Screen.background, Screen.canvas, Screen.canvasPos);
         SDL_RenderCopy(renderer, player.texture, player.shipFrame, player.position);
         SDL_RenderCopy(renderer, player.propeller, player.propellerFrame, player.propellerPos);
         SDL_RenderCopy(renderer, player.shooter, player.shooterFrame, player.shooterPos);
-
+        // Iterate over the bullets on the screen
         for(Iterator<PlayerBullet> bulletIterator = playerBullets.iterator(); bulletIterator.hasNext();){
             PlayerBullet b = bulletIterator.next();
+            // Move the bullet
             b.fly();
+            // If the bullet is out of the screen, destroy it, else copy it to the renderer.
             if(b.position.y < 30){
                 bulletIterator.remove();
             } else {
                 SDL_RenderCopy(renderer, PlayerBullet.texture, null, b.position);
             }
         }
-
+        // Present the renderer to the window.
         SDL_RenderPresent(renderer);
+        // Advance player sprite animation
         player.shiftFrame();
     }
 }

src/main/java/com/fmudanyali/scenes/Scene.java

@@ -17,6 +17,20 @@
 
 package com.fmudanyali.scenes;
 
+/**
+ * <h3>Scene Class</h3>
+ * 
+ * This class is an abstract for other scenes and makes able to
+ * keep all the different kind of scenes on a single stack.
+ * 
+ * @author Furkan Mudanyali
+ * @version 1.0.0
+ * @since 2021-12-04
+ */
 public abstract class Scene {
+    /**
+     * By design, this function will be
+     * executed each game frame.
+     */
     public abstract void loop();
 }