Lecture 4

1. Lecture 4 XNA Review Richard Gesick

2. TheMajor Methods of an XNA Game Constructor - initialize and set up variables as usual LoadContent - load SpriteFont, Texture2D, etc. Update - handle all user input and update game state Draw - handle drawing the images/graphics to the screen

3. NO drawing should happen in Update and No input/state changes should happen in Draw

4. Content Draw your assets (using transparent backgrounds if desired) in your favorite paint program.  GIMP and Paint.NET are both free Add your assets to the Content folder and then add them to your project (via "Project | Add | Add Existing...")

5. Create attributes within the class to hold the assets Texture2D bowl; then Load the assets into the attributes in the LoadContent method bowl = Content.Load<Texture2D>("bowl");

6. User Input Handle user input (via the GetState method of the Keyboard class) currentKeyboardState= Keyboard.GetState(PlayerIndex.One); if (currentKeyboardState.IsKeyDown(Keys.Left)) { bowl_position.X -= 3; if (bowl_position.X < 0) bowl_position.X = 0; } . . .

7. Draw(1) Draw icons/sprites to the screen (via the Draw method of the SpriteBatch class) GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); spriteBatch.Draw(bowl,bowl_position, Color.White);

8. Draw (2) Draw strings to the screen (via the DrawString method of the SpriteBatch class) spriteBatch.DrawString(stats_font, "Food consumed: " + FoodCaught, pos, Color.White); Be sure to place all screen manipulation inside the Begin/End methods of the SpriteBatch class

9. Random numbers Random r; … r = new Random(); … = r.Next(1, 4); // values 1 to 3 = r.Next(-100, 100); //values -100 to 99 = r.Next(100) //values 0 to 99

10. List<T> List<> is a parameterized collection class that is useful for storing dynamic collections of items; use the Add, Remove, RemoveAt, etc. methods falling_food = new List<FoodItem>(); … falling_food.Add(fi);

11. Tutorial Link Tutorial courtesy of Dr. J. Preston. audio/video tutorials cse1302_Lecture4_FoodWars.zip