I’m doing a college assignment in XNA to make a virtual piano.
I have 2 classes, Piano ( my base class) and PianoNotes ( mysubclass)
I have values declared in Piano,which are used in PianoNotes ( inheritance )
and override functions that use polymorphism.
However when I call the draw function in my Game1 file ( equivalent of main I believe),
nothing appears.
Can someone tell me where I am going wrong?
Here is my code – Game 1 File
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace PianoAttempt1
{
/// <summary>
/// This is a piano , using pre-recorded wav files
/// It will have 88 notes
///
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
// Used to draw sprites (2D bitmaps)
public SpriteBatch spriteBatch;
// Instance is a STATIC member, meaning that there is only one of them
// No matter how many instances are created
public static Game1 Instance;
public List<Piano> children = new List<Piano>();
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
// Set back buffer resolution
graphics.PreferredBackBufferWidth = 820;
graphics.PreferredBackBufferHeight = 640;
Instance = this; // Creates an instance of the piano class
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
// call a "new" version of piano notes?
children.Add(new Piano());
for (int i = 0; i < children.Count(); i++)
{
children[i].LoadContent();
}
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
///
protected override void Update(GameTime gameTime)
{
KeyboardState keyState = Keyboard.GetState();
if (keyState.IsKeyDown(Keys.Escape))
{
this.Exit();
}
base.Update(gameTime);
}
protected override void Draw(GameTime gameTime)
{
//GraphicsDevice.Clear(Color.Green); // This works meaning there is something wrong with the draw function...
// Start drawing sprites, front to back
spriteBatch.Begin(SpriteSortMode.FrontToBack, BlendState.Opaque);
// Tell all the objects in the scene to draw themselves
for (int i = 0; i < children.Count(); i++)
{
children[i].Draw(gameTime);
}
spriteBatch.End();
base.Draw(gameTime);
}
}
}
Piano File
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace PianoAttempt1
{
public class Piano // Base class of all the other classes
{
protected Texture2D Sprite; // Piano bitmap
protected SoundEffect Sound1; // Oct1NoteC
protected SoundEffect Sound2; // Oct1NoteC#
protected SoundEffect Sound3; // Oct1NoteD
protected SoundEffect Sound4; // Oct1NoteD#
protected SoundEffect Sound5; // Oct1NoteE
protected SoundEffect Sound6; // Oct1NoteF
protected SoundEffect Sound7; // Oct1NoteF#
protected SoundEffect Sound8; // Oct1NoteG
protected SoundEffect Sound9; // Oct1NoteG#
protected SoundEffect Sound10; // Oct1NoteA
protected SoundEffect Sound11; // Oct1NoteA#
protected SoundEffect Sound12; // Oct1NoteB
protected SoundEffect Sound13; // Oct2NoteC
protected SoundEffect Sound14; // Oct2NoteC#
protected SoundEffect Sound15; // Oct2NoteD
protected SoundEffect Sound16; // Oct2NoteD#
protected SoundEffect Sound17; // Oct2NoteE
protected SoundEffect Sound18; // Oct2NoteF
protected SoundEffect Sound19; // Oct2NoteF#
protected SoundEffect Sound20; // Oct2NoteG
protected SoundEffect Sound21; // Oct2NoteG
protected SoundEffect Sound22; // Oct2NoteG
protected SoundEffect Sound23; // Oct2NoteG
protected SoundEffect Sound24; // Oct2NoteG#
protected SoundEffect Sound25; // Oct2NoteA
protected SoundEffect Sound26; // Oct2NoteA#
protected SoundEffect Sound27; // Oct2NoteB
public Vector2 Position; // Position of the piano sprite
public Vector2 Look;
public Vector2 Center;
public float Rotation;
public virtual void LoadContent()
{
}
public virtual void Update(GameTime gameTime)
{
}
public virtual void Draw(GameTime gameTime)
{
}
}
}
Piano Notes File
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace PianoAttempt1
{
class PianoNotes : Piano // Extends Piano , it is a subclass of Piano
{
public override void LoadContent()
{
// Load the audio files from the content pipeline. No need to include file type
//-------------- Piano Bitmap ----------------------------------
Position.X = 100;
Position.Y = 5;
Sprite = Game1.Instance.Content.Load<Texture2D>("piano_sample");
Center.X = Sprite.Width / 2;
Center.Y = Sprite.Height / 2;
Rotation = 0;
//------------------------------------------------------------
Sound1 = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteC");
//Sound2 = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteC#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteD");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteD#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteE");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteF");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteF#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteG");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteG#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteA");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteA#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct1NoteB");
//------------ Octave 2 -----------------------
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteC");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteC#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteD");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteD#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteE");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteF");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteF#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteG");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteG#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteA");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteA#");
//Sound = Game1.Instance.Content.Load<SoundEffect>("Oct2NoteB");
base.LoadContent();
}
public override void Update(GameTime gameTime)
{
base.Update(gameTime);
// Gets the state of the keyboard , allowing the user to use the keys to play..
KeyboardState keyState = Keyboard.GetState();
if (keyState.IsKeyDown(Keys.Up))
{
Sound1.Play();
}
}
public override void Draw(GameTime gameTime)
{
// Draw the piano sprite
Game1.Instance.spriteBatch.Draw(Sprite, Position, null, Color.SkyBlue, Rotation, Center, 1, SpriteEffects.None, 1);
base.Draw(gameTime);
}
}
}
In the Game1.LoadContent() method, you need to change
to
so that when you go to draw the children in Game1.Draw(), this uses the PianoNote’s Draw() implementation, rather than the empty Piano.Draw() base class method.
The children collection type is fine.
As a side note – depending how many items end up in this collection, you might want to consider using an alternative to virtual methods, as they are known to be about 40% slower in execution for Xbox360 deployments.
more @ http://blogs.msdn.com/b/netcfteam/archive/2005/05/04/414820.aspx
and http://msdn.microsoft.com/en-us/library/bb203912.aspx