add tutorial 2 comments

ROADMAP.txt

@@ -1,7 +1,5 @@
 ------------ Tyra's v2.0 roadmap to publish on GitHub ------------
 
-- [Tutorials] 2. 2D - explain beginFrame(), endFrame()
-
 - [Tutorials] 3. Minecraft cube - explain this pipeline, and explain that there are many 3D pipelines
 
 - [Tutorials] 4. Mesh rendering - explain staticPipeline, render .obj file via Mesh class, explain that this is high-level 

engine/inc/renderer/renderer.hpp

@@ -35,6 +35,8 @@ class Renderer {
     core.setClearScreenColor(color);
   }
 
+  TextureRepository& getTextureRepository() { return core.texture.repository; }
+
   void setFrameLimit(const bool& onoff) { core.setFrameLimit(onoff); }
 
   /** Update view frustum for frustum culling. 3D support - off */

tutorials/02-sprite/src/tutorial_02.cpp

@@ -14,11 +14,17 @@
 namespace Tyra {
 
 Tutorial02::Tutorial02(Engine* t_engine) : engine(t_engine) {
+  /** Lets set default value, to prevent nullptr bugs */
   texture = nullptr;
 }
 
 Tutorial02::~Tutorial02() {
   if (texture != nullptr) {
+    /**
+     * free() function in texture repository is
+     * removing texture from repository and calling
+     * texture destructor
+     */
     engine->renderer.core.texture.repository.free(texture);
   }
 }
@@ -33,8 +39,13 @@ void Tutorial02::init() {
 void Tutorial02::loop() {
   auto& renderer = engine->renderer;
 
+  /** Begin frame will clear our screen. */
   renderer.beginFrame();
+
+  /** Render sprite. */
   renderer.renderer2D.render(sprite);
+
+  /** End frame will perform vsync. */
   renderer.endFrame();
 }
 
@@ -42,7 +53,11 @@ void Tutorial02::loadSprite() {
   const auto& screenSettings = engine->renderer.core.getSettings();
 
   sprite.mode = SpriteMode::MODE_STRETCH;
+
+  /** Let's scale it down */
   sprite.size = Vec2(256.0F, 128.0F);
+
+  /** Set it in screen center */
   sprite.position =
       Vec2(screenSettings.getWidth() / 2.0F - sprite.size.x / 2.0F,
            screenSettings.getHeight() / 2.0F - sprite.size.y / 2.0F);
@@ -51,13 +66,51 @@ void Tutorial02::loadSprite() {
 }
 
 void Tutorial02::loadTexture() {
+  /**
+   * Renderer has high layer functions,
+   * which allows to render:
+   * - Sprite (2D)
+   * - Mesh (3D)
+   *
+   * It uses ONLY low layer functions which are in renderer.core
+   */
   auto& renderer = engine->renderer;
-  auto& rendererCore = renderer.core;
-  auto& textureRepository = rendererCore.texture.repository;
 
+  /**
+   * TextureRepository is a repository of textures.
+   * It is a singleton class, with all game textures.
+   * We are linking these textures with sprite's (2D) and mesh (3D) materials.
+   */
+  auto& textureRepository = renderer.getTextureRepository();
+
+  /**
+   * Texture is stored in "res" directory.
+   * Content of "res" directory is automatically copied into
+   * "bin" directory, which contains our final game.
+   *
+   * File utils automatically add's device prefix to the path,
+   * based on current working directory.
+   *
+   * In PS2 world:
+   * - USB has a "mass:" prefix
+   * - Our PC in PS2Link has a "host:" prefix
+   * - Our PC in PCSX2 has a "host:" prefix
+   */
   auto filepath = FileUtils::fromCwd("tyra.png");
+
+  /**
+   * Tyra supports following PNG formats:
+   * 32bpp (RGBA)
+   * 24bpp (RGB)
+   * 8bpp, palletized (RGBA)
+   * 4bpp, palletized (RGBA)
+   *
+   * 8bpp and 4bpp are the fastest.
+   * All of these formats can be easily exported via GIMP.
+   */
   texture = textureRepository.add(filepath);
 
+  /** Let's assign this texture to sprite. */
   texture->addLink(sprite.id);
 
   TYRA_LOG("Texture loaded!");