Joystick
From SDL.NET
| Table of contents |
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Introduction
SDL.NET supports joystick input. This tutorial will show how to move a custom cursor around the screen using a joystick. Also, pressing the joystick button will print to the console.
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Initialization
To intialize the joystick subsystem just instantiate a Joystick object.
Joystick joystick = Joysticks.OpenJoystick(0);
This creates a joystick object that is represents the first joystick found on the system.
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Events
The Events class contains several Joystick-related events.
JoystickAxisMotion // Movement JoystickButtonDown // Button pressed JoystickButtonUp // Button released JoystickHatMotion // Hat motion JoystickBallMotion // Ball motion
Each event can be bound to an event handler which will fire off an appropriate method such as:
// This method will set the position of the cursor accroding to the movement of the joystick.
private void JoystickAxisChanged(object sender, JoystickAxisEventArgs e)
{
if (e.AxisIndex == 0)
{
position.X = (int)(joystick.GetAxisPosition(JoystickAxis.Horizontal) * width);
}
else if (e.AxisIndex == 1)
{
position.Y = (int)(joystick.GetAxisPosition(JoystickAxis.Vertical) * height);
}
}
// This method will simply print to the console when the button is pressed.
private void JoystickButtonDown(object sender, JoystickButtonEventArgs e)
{
Console.WriteLine("Joystick button was pressed");
}
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Data Files
The tutorial uses this graphic file (cursor.png) as a custom cursor that responds to joystick movement.
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Full Source Code
using System;
using System.Drawing;
using System.Threading;
using System.IO;
using System.Runtime.InteropServices;
using SdlDotNet.Graphics;
using SdlDotNet.Input;
using SdlDotNet.Audio;
using SdlDotNet.Core;
namespace SdlDotNetExamples.SmallDemos
{
public class JoystickExample : IDisposable
{
Point position = new Point(100, 100);
int width = 640;
int height = 480;
Joystick joystick;
Surface screen;
Surface cursor;
/// <summary>
///
/// </summary>
public JoystickExample()
{
}
/// <summary>
///
/// </summary>
public void Go()
{
string filePath = Path.Combine("..", "..");
string fileDirectory = "Data";
string fileName = "cursor.png";
if (File.Exists(fileName))
{
filePath = "";
fileDirectory = "";
}
else if (File.Exists(Path.Combine(fileDirectory, fileName)))
{
filePath = "";
}
string file = Path.Combine(Path.Combine(filePath, fileDirectory), fileName);
Events.Tick += new EventHandler<TickEventArgs>(Tick);
Events.KeyboardDown +=
new EventHandler<KeyboardEventArgs>(this.KeyboardDown);
Events.Quit += new EventHandler<QuitEventArgs>(this.Quit);
Events.JoystickAxisMotion +=
new EventHandler<JoystickAxisEventArgs>(this.JoystickAxisChanged);
Events.JoystickButtonDown += new EventHandler<JoystickButtonEventArgs>(this.JoystickButtonDown);
joystick = Joysticks.OpenJoystick(0);
try
{
Video.WindowIcon();
Video.WindowCaption = "SdlDotNet - Joystick Example";
screen = Video.SetVideoMode(width, height, true);
Mouse.ShowCursor = false; // hide the cursor
Surface surf =
screen.CreateCompatibleSurface(width, height, true);
surf.Fill(new Rectangle(new Point(0, 0),
surf.Size), System.Drawing.Color.Black);
cursor = new Surface(file);
Events.Run();
}
catch
{
throw;
}
}
private void Tick(object sender, TickEventArgs e)
{
screen.Fill(Color.Black);
screen.Blit(cursor, new Rectangle(position, screen.Size));
screen.Update();
}
private void KeyboardDown(object sender, KeyboardEventArgs e)
{
if (e.Key == Key.Escape ||
e.Key == Key.Q)
{
Events.QuitApplication();
}
}
private void Quit(object sender, QuitEventArgs e)
{
Events.QuitApplication();
}
private void JoystickAxisChanged(object sender, JoystickAxisEventArgs e)
{
if (e.AxisIndex == 0)
{
position.X = (int)(joystick.GetAxisPosition(JoystickAxis.Horizontal) * width);
}
else if (e.AxisIndex == 1)
{
position.Y = (int)(joystick.GetAxisPosition(JoystickAxis.Vertical) * height);
}
}
private void JoystickButtonDown(object sender, JoystickButtonEventArgs e)
{
Console.WriteLine("Joystick button was pressed");
}
/// <summary>
/// Application EntryPoint.
/// </summary>
[STAThread]
public static void Main()
{
JoystickExample joystickExample = new JoystickExample();
joystickExample.Go();
}
/// <summary>
/// Lesson Title
/// </summary>
public static string Title
{
get
{
return "JoystickExample: Move the cursor with a joystick";
}
}
#region IDisposable Members
private bool disposed;
/// <summary>
///
/// </summary>
/// <param name="disposing"></param>
protected virtual void Dispose(bool disposing)
{
if (!this.disposed)
{
if (disposing)
{
if (this.screen != null)
{
this.screen.Dispose();
this.screen = null;
}
if (this.cursor != null)
{
this.cursor.Dispose();
this.cursor = null;
}
if (this.joystick != null)
{
this.joystick.Dispose();
this.joystick = null;
}
}
this.disposed = true;
}
}
/// <summary>
///
/// </summary>
public void Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
/// <summary>
///
/// </summary>
public void Close()
{
Dispose();
}
/// <summary>
///
/// </summary>
~JoystickExample()
{
Dispose(false);
}
#endregion
}
}
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