In our previous sample we have seen how to use Microphone device. Now we will be talking about Webcam.
For Webcam we have several alternatives.Com Registration and DirectShow.
I have chosen the DirectShow way! Let me remind one thing: DirectShowLib says No Warranty what happens to your webcam or computer,so I shall tell you so :)
Its much more easier and no-com register at all.
Ok lets start!
Create a new XNA 4.0 Windows Game Project(i named it WebCamXNA)
Add these namespaces and references to your project.
System
System.Drawing
DirectShowLib
using System.Windows.Forms;
using DirectShowLib;
using System.Drawing;
Then add Capture.cs file to your project there are lots of comments so no need to explain further :) but if you need me to explain,please write a comment under this article so i would be more helpful;
Which has this structure:
using System;
using
System.Drawing;
using
System.Drawing.Imaging;
using
System.Collections;
using
System.Runtime.InteropServices;
using
System.Threading;
using
System.Diagnostics;
using
System.Windows.Forms;
using
DirectShowLib;
namespace WebCamXNA
{
internal
class Capture
: ISampleGrabberCB, IDisposable
{
#region Member variables
/// <summary> graph builder interface. </summary>
private IFilterGraph2
m_FilterGraph = null;
// Used to snap picture on Still pin
private IAMVideoControl
m_VidControl = null;
private IPin m_pinStill = null;
/// <summary> so we can wait for the async job to finish </summary>
private ManualResetEvent
m_PictureReady = null;
private bool m_WantOne = false;
/// <summary> Dimensions of the image, calculated once in constructor
for perf. </summary>
private int m_videoWidth;
private int m_videoHeight;
private int m_stride;
/// <summary> buffer for bitmap data.
Always release by caller</summary>
private IntPtr m_ipBuffer = IntPtr.Zero;
#if DEBUG
// Allow you to "Connect to remote graph" from GraphEdit
DsROTEntry m_rot = null;
#endif
#endregion
#region APIs
[DllImport("Kernel32.dll",
EntryPoint="RtlMoveMemory")]
private static extern void
CopyMemory(IntPtr Destination, IntPtr Source, [MarshalAs(UnmanagedType.U4)] int
Length);
#endregion
// Zero based device index and device params and output window
public Capture(int iDeviceNum, int iWidth, int
iHeight, short iBPP, Control
hControl)
{
DsDevice [] capDevices;
// Get the collection of video devices
capDevices = DsDevice.GetDevicesOfCat(FilterCategory.VideoInputDevice);
if (iDeviceNum + 1 > capDevices.Length)
{
throw new Exception("No
video capture devices found at that index!");
}
try
{
// Set up the capture graph
SetupGraph(
capDevices[iDeviceNum], iWidth, iHeight, iBPP, hControl);
// tell the
callback to ignore new images
m_PictureReady
= new ManualResetEvent(false);
}
catch
{
Dispose();
throw;
}
}
/// <summary> release everything. </summary>
public void Dispose()
{
#if DEBUG
if (m_rot != null)
{
m_rot.Dispose();
}
#endif
CloseInterfaces();
if (m_PictureReady != null)
{
m_PictureReady.Close();
}
}
// Destructor
~Capture()
{
Dispose();
}
/// <summary>
/// Get the image from the Still
pin. The returned image can turned into
a bitmap with
/// Bitmap b = new Bitmap(cam.Width,
cam.Height, cam.Stride, PixelFormat.Format24bppRgb, m_ip);
/// If the image is upside down, you can
fix it with
///
b.RotateFlip(RotateFlipType.RotateNoneFlipY);
/// </summary>
/// <returns>Returned pointer to be freed by caller with
Marshal.FreeCoTaskMem</returns>
public IntPtr Click()
{
int hr;
// get ready to wait for new image
m_PictureReady.Reset();
m_ipBuffer = Marshal.AllocCoTaskMem(Math.Abs(m_stride)
* m_videoHeight);
try
{
m_WantOne = true;
// If we are using a still pin, ask for a picture
if (m_VidControl != null)
{
// Tell the camera to send an image
hr =
m_VidControl.SetMode(m_pinStill, VideoControlFlags.Trigger);
DsError.ThrowExceptionForHR( hr );
}
// Start waiting
if ( ! m_PictureReady.WaitOne(9000, false) )
{
throw new Exception("Timeout
waiting to get picture");
}
}
catch
{
Marshal.FreeCoTaskMem(m_ipBuffer);
m_ipBuffer = IntPtr.Zero;
throw;
}
// Got one
return m_ipBuffer;
}
public int Width
{
get
{
return m_videoWidth;
}
}
public int Height
{
get
{
return m_videoHeight;
}
}
public int Stride
{
get
{
return m_stride;
}
}
/// <summary> build the capture graph for grabber. </summary>
private void SetupGraph(DsDevice dev, int
iWidth, int iHeight, short
iBPP, Control hControl)
{
int hr;
ISampleGrabber sampGrabber = null;
IBaseFilter capFilter = null;
IPin pCaptureOut = null;
IPin pSampleIn = null;
IPin pRenderIn = null;
// Get the graphbuilder object
m_FilterGraph = new FilterGraph() as IFilterGraph2;
try
{
#if DEBUG
m_rot = new DsROTEntry(m_FilterGraph);
#endif
// add the video input device
hr =
m_FilterGraph.AddSourceFilterForMoniker(dev.Mon, null,
dev.Name, out capFilter);
DsError.ThrowExceptionForHR( hr );
// Find the still pin
m_pinStill = DsFindPin.ByCategory(capFilter, PinCategory.Still, 0);
// Didn't find one.
Is there a preview pin?
if (m_pinStill == null)
{
m_pinStill
= DsFindPin.ByCategory(capFilter, PinCategory.Preview, 0);
}
// Still
haven't found one. Need to put a
splitter in so we have
// one stream to capture the bitmap from, and one to
display. Ok, we
// don't *have* to do it that way, but we are going to
anyway.
if (m_pinStill == null)
{
IPin pRaw = null;
IPin pSmart = null;
// There is no still pin
m_VidControl = null;
// Add a splitter
IBaseFilter iSmartTee = (IBaseFilter)new SmartTee();
try
{
hr =
m_FilterGraph.AddFilter(iSmartTee, "SmartTee");
DsError.ThrowExceptionForHR( hr );
// Find the find the capture pin from the video device and
the
// input pin for the splitter, and connnect them
pRaw = DsFindPin.ByCategory(capFilter, PinCategory.Capture, 0);
pSmart = DsFindPin.ByDirection(iSmartTee, PinDirection.Input, 0);
hr =
m_FilterGraph.Connect(pRaw, pSmart);
DsError.ThrowExceptionForHR( hr );
// Now set the capture and still pins (from the splitter)
m_pinStill = DsFindPin.ByName(iSmartTee,
"Preview");
pCaptureOut = DsFindPin.ByName(iSmartTee,
"Capture");
// If any of the default config items are set, perform the
config
// on the actual video device (rather than the splitter)
if (iHeight + iWidth + iBPP > 0)
{
SetConfigParms(pRaw, iWidth, iHeight, iBPP);
}
}
finally
{
if (pRaw != null)
{
Marshal.ReleaseComObject(pRaw);
}
if (pRaw != pSmart)
{
Marshal.ReleaseComObject(pSmart);
}
if (pRaw != iSmartTee)
{
Marshal.ReleaseComObject(iSmartTee);
}
}
}
else
{
// Get a control pointer (used in Click())
m_VidControl
= capFilter as IAMVideoControl;
pCaptureOut
= DsFindPin.ByCategory(capFilter, PinCategory.Capture, 0);
// If any of the default config items are set
if (iHeight + iWidth + iBPP > 0)
{
SetConfigParms(m_pinStill, iWidth, iHeight, iBPP);
}
}
// Get the SampleGrabber interface
sampGrabber = new SampleGrabber()
as ISampleGrabber;
// Configure the sample grabber
IBaseFilter baseGrabFlt = sampGrabber as IBaseFilter;
ConfigureSampleGrabber(sampGrabber);
pSampleIn = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Input, 0);
// Get the default video renderer
IBaseFilter pRenderer = new
VideoRendererDefault() as IBaseFilter;
hr =
m_FilterGraph.AddFilter(pRenderer, "Renderer");
DsError.ThrowExceptionForHR( hr );
pRenderIn = DsFindPin.ByDirection(pRenderer, PinDirection.Input, 0);
// Add the sample grabber to the graph
hr =
m_FilterGraph.AddFilter( baseGrabFlt, "Ds.NET
Grabber" );
DsError.ThrowExceptionForHR( hr );
if (m_VidControl == null)
{
// Connect the Still pin to the sample grabber
hr =
m_FilterGraph.Connect(m_pinStill, pSampleIn);
DsError.ThrowExceptionForHR( hr );
// Connect the capture pin to the renderer
hr =
m_FilterGraph.Connect(pCaptureOut, pRenderIn);
DsError.ThrowExceptionForHR( hr );
}
else
{
// Connect the capture pin to the renderer
hr =
m_FilterGraph.Connect(pCaptureOut, pRenderIn);
DsError.ThrowExceptionForHR( hr );
// Connect the Still pin to the sample grabber
hr =
m_FilterGraph.Connect(m_pinStill, pSampleIn);
DsError.ThrowExceptionForHR( hr );
}
// Learn the video properties
SaveSizeInfo(sampGrabber);
ConfigVideoWindow(hControl);
// Start the graph
IMediaControl mediaCtrl = m_FilterGraph as IMediaControl;
hr =
mediaCtrl.Run();
DsError.ThrowExceptionForHR( hr );
}
finally
{
if (sampGrabber != null)
{
Marshal.ReleaseComObject(sampGrabber);
sampGrabber
= null;
}
if (pCaptureOut != null)
{
Marshal.ReleaseComObject(pCaptureOut);
pCaptureOut
= null;
}
if (pRenderIn != null)
{
Marshal.ReleaseComObject(pRenderIn);
pRenderIn =
null;
}
if (pSampleIn != null)
{
Marshal.ReleaseComObject(pSampleIn);
pSampleIn =
null;
}
}
}
private void SaveSizeInfo(ISampleGrabber sampGrabber)
{
int hr;
// Get the media type from the SampleGrabber
AMMediaType media = new
AMMediaType();
hr =
sampGrabber.GetConnectedMediaType( media );
DsError.ThrowExceptionForHR( hr );
if( (media.formatType != FormatType.VideoInfo)
|| (media.formatPtr == IntPtr.Zero) )
{
throw new NotSupportedException( "Unknown
Grabber Media Format" );
}
// Grab the size info
VideoInfoHeader videoInfoHeader = (VideoInfoHeader) Marshal.PtrToStructure(
media.formatPtr, typeof(VideoInfoHeader) );
m_videoWidth =
videoInfoHeader.BmiHeader.Width;
m_videoHeight =
videoInfoHeader.BmiHeader.Height;
m_stride =
m_videoWidth * (videoInfoHeader.BmiHeader.BitCount / 8);
DsUtils.FreeAMMediaType(media);
media = null;
}
// Set the video window within the control specified by hControl
private void ConfigVideoWindow(Control hControl)
{
int hr;
IVideoWindow ivw = m_FilterGraph as IVideoWindow;
// Set the parent
hr =
ivw.put_Owner(hControl.Handle);
DsError.ThrowExceptionForHR( hr );
// Turn off captions, etc
hr =
ivw.put_WindowStyle(WindowStyle.Child | WindowStyle.ClipChildren | WindowStyle.ClipSiblings);
DsError.ThrowExceptionForHR(
hr );
// Yes, make it visible
hr =
ivw.put_Visible( OABool.True );
DsError.ThrowExceptionForHR( hr );
// Move to upper left corner
Rectangle rc = hControl.ClientRectangle;
hr =
ivw.SetWindowPosition( 0, 0, rc.Right, rc.Bottom );
DsError.ThrowExceptionForHR( hr );
}
private void
ConfigureSampleGrabber(ISampleGrabber
sampGrabber)
{
int hr;
AMMediaType media = new
AMMediaType();
// Set the media type to Video/RBG24
media.majorType = MediaType.Video;
media.subType = MediaSubType.RGB24;
media.formatType = FormatType.VideoInfo;
hr = sampGrabber.SetMediaType( media
);
DsError.ThrowExceptionForHR( hr );
DsUtils.FreeAMMediaType(media);
media = null;
// Configure the samplegrabber
hr =
sampGrabber.SetCallback( this, 1 );
DsError.ThrowExceptionForHR( hr );
}
// Set the Framerate, and video size
private void SetConfigParms(IPin pStill, int
iWidth, int iHeight, short
iBPP)
{
int hr;
AMMediaType media;
VideoInfoHeader v;
IAMStreamConfig videoStreamConfig = pStill as IAMStreamConfig;
// Get the existing format block
hr =
videoStreamConfig.GetFormat(out media);
DsError.ThrowExceptionForHR(hr);
try
{
// copy out the videoinfoheader
v = new VideoInfoHeader();
Marshal.PtrToStructure( media.formatPtr, v );
// if overriding the width, set the width
if
(iWidth > 0)
{
v.BmiHeader.Width = iWidth;
}
// if overriding the Height, set the Height
if (iHeight > 0)
{
v.BmiHeader.Height = iHeight;
}
// if overriding the bits per pixel
if (iBPP > 0)
{
v.BmiHeader.BitCount = iBPP;
}
// Copy the media structure back
Marshal.StructureToPtr( v, media.formatPtr, false );
// Set the new format
hr =
videoStreamConfig.SetFormat( media );
DsError.ThrowExceptionForHR( hr );
}
finally
{
DsUtils.FreeAMMediaType(media);
media = null;
}
}
/// <summary> Shut down capture </summary>
private void CloseInterfaces()
{
int hr;
try
{
if( m_FilterGraph != null
)
{
IMediaControl mediaCtrl = m_FilterGraph as IMediaControl;
// Stop the graph
hr =
mediaCtrl.Stop();
}
}
catch (Exception
ex)
{
Debug.WriteLine(ex);
}
if (m_FilterGraph != null)
{
Marshal.ReleaseComObject(m_FilterGraph);
m_FilterGraph =
null;
}
if (m_VidControl != null)
{
Marshal.ReleaseComObject(m_VidControl);
m_VidControl = null;
}
if (m_pinStill != null)
{
Marshal.ReleaseComObject(m_pinStill);
m_pinStill = null;
}
}
/// <summary> sample callback, NOT USED. </summary>
int ISampleGrabberCB.SampleCB( double SampleTime, IMediaSample
pSample )
{
Marshal.ReleaseComObject(pSample);
return 0;
}
/// <summary> buffer callback, COULD BE FROM FOREIGN THREAD. </summary>
int ISampleGrabberCB.BufferCB( double SampleTime, IntPtr
pBuffer, int BufferLen )
{
// Note that we depend on only being called once per call
to Click. Otherwise
// a second call can overwrite the previous image.
Debug.Assert(BufferLen == Math.Abs(m_stride)
* m_videoHeight, "Incorrect buffer
length");
if (m_WantOne)
{
m_WantOne = false;
Debug.Assert(m_ipBuffer != IntPtr.Zero, "Unitialized
buffer");
// Save the buffer
CopyMemory(m_ipBuffer, pBuffer,
BufferLen);
// Picture is ready.
m_PictureReady.Set();
}
return 0;
}
}
}
This is our class that will capture our WebCam device.
How will we use it?
Open your Game1.cs class and write these code:
Add these namespaces:
using
System.Runtime.InteropServices;
using
System.Windows.Forms;
using
System.Drawing;
using
System.Drawing.Imaging;
Add these variables:
private
System.Windows.Forms.Button button1;
private
System.Windows.Forms.PictureBox
pictureBox1;
private
System.ComponentModel.Container components =
null;
private
System.Windows.Forms.PictureBox pictureBox2;
private Capture cam;
IntPtr m_ip = IntPtr.Zero;
Create a Dispose Function:
protected override void
Dispose(bool disposing)
{
if
(disposing)
{
if
(components != null)
{
components.Dispose();
}
}
base.Dispose(disposing);
if
(m_ip != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(m_ip);
m_ip = IntPtr.Zero;
}
}
Add these codes inside Initialize function which loads 2 picturebox,a button and a camera
this.button1 = new System.Windows.Forms.Button();
this.pictureBox1
= new System.Windows.Forms.PictureBox();
this.pictureBox2
= new System.Windows.Forms.PictureBox();
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).BeginInit();
//
// button1
//
this.button1.Location
= new System.Drawing.Point(368,
80);
this.button1.Name
= "button1";
this.button1.Size
= new System.Drawing.Size(75,
40);
this.button1.TabIndex
= 0;
this.button1.Text
= "Click";
this.button1.Click
+= new System.EventHandler(this.button1_Click);
//
// pictureBox1
//
this.pictureBox1.BorderStyle
= System.Windows.Forms.BorderStyle.FixedSingle;
this.pictureBox1.Location
= new System.Drawing.Point(16,
256);
this.pictureBox1.Name
= "pictureBox1";
this.pictureBox1.Size
= new System.Drawing.Size(320,
240);
this.pictureBox1.TabIndex
= 1;
this.pictureBox1.TabStop
= false;
//
// pictureBox2
//
this.pictureBox2.BorderStyle
= System.Windows.Forms.BorderStyle.FixedSingle;
this.pictureBox2.Location
= new System.Drawing.Point(16,
8);
this.pictureBox2.Name
= "pictureBox2";
this.pictureBox2.Size
= new System.Drawing.Size(320,
240);
this.pictureBox2.TabIndex
= 2;
this.pictureBox2.TabStop
= false;
Control.FromHandle(Window.Handle).Controls.Add(pictureBox1);
Control.FromHandle(Window.Handle).Controls.Add(pictureBox2);
Control.FromHandle(Window.Handle).Controls.Add(button1);
const int VIDEODEVICE = 0; //
zero based index of video capture device to use
const int VIDEOWIDTH = 320; //
Depends on video device caps
const int VIDEOHEIGHT = 240; //
Depends on video device caps
const int VIDEOBITSPERPIXEL = 24; //
BitsPerPixel values determined by device
cam = new Capture(VIDEODEVICE,
VIDEOWIDTH, VIDEOHEIGHT, VIDEOBITSPERPIXEL, pictureBox2);
Create a Button Click event
private void button1_Click(object
sender, System.EventArgs e)
{
Cursor.Current
= Cursors.WaitCursor;
//
Release any previous buffer
if
(m_ip != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(m_ip);
m_ip = IntPtr.Zero;
}
//
capture image
m_ip = cam.Click();
Bitmap
b = new Bitmap(cam.Width,
cam.Height, cam.Stride, PixelFormat.Format24bppRgb,
m_ip);
//
If the image is upsidedown
b.RotateFlip(RotateFlipType.RotateNoneFlipY);
pictureBox1.Image = b;
Cursor.Current
= Cursors.Default;
}
Update your UnloadContent function as shown below:
protected override void UnloadContent()
{
cam.Dispose();
if
(m_ip != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(m_ip);
m_ip = IntPtr.Zero;
}
}
And now run the project and see what happens!
Picturebox1 displays webcam output,Picturebox 2 will show your picture when clicked the button.
Here looking at camera :)
And now I have took a photo of mine and showed it on Picturebox2 :)
Nice! isnt it? Ok not me perhaps but the project itself :) :)
We have added Webcam functionality to our game but whats the point?
What can you do with Webcam in a game?
You can develop Game-Version of ChatRoulette.in which 2 players view their camera in picturebox1 and picturebox2.And in the right corner they can play nice games such as Chess,Card Games(Hearts,FreeCell) or anything you can imagine ;)
And that would be a great game and even celebs can play with you :)
Allright I showed you today how to use webcam functionality in games with a nice demo.
Hope you like it!
See you in other articles ;)
Cheers