# Matrix Structure

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

Describes and manipulates a matrix.

Namespace:  Microsoft.WindowsMobile.DirectX
Assembly:  Microsoft.WindowsMobile.DirectX (in Microsoft.WindowsMobile.DirectX.dll)

## Syntax

``````'Declaration
Public Structure Matrix
'Usage
Dim instance As Matrix
``````
``````public struct Matrix
``````
``````public value class Matrix
``````
``````[<SealedAttribute>]
type Matrix =  struct end
``````

## Remarks

This structure represents a 4 × 4 matrix of single-precision floating-point numbers. The fields of this structure are named with the row number first, then the column number.

In Microsoft Windows Mobile Direct3D, the M34 element of a projection matrix cannot be a negative number. If an application needs to use a negative value in this location, it should scale the entire projection matrix by –1 instead.

## Examples

The following example shows how to use a Matrix structure.

``````' This code example is from the Direct3D Mobile Matrices Sample
' in the .NET Compact Framework Samples in the SDK.
Private Sub SetupMatrices()
' For the world matrix, rotate the object about the y-axis.
' Set up the rotation matrix to generate one full rotation (2*PI radians)
' every 1000 ms. To avoid the loss of precision inherent in very high
' floating-point numbers, the system time is modulated by the rotation
' period before conversion to a radian angle.
Dim iTime As Integer = Environment.TickCount Mod 1000
Dim fAngle As Single = iTime * (2.0F * System.Convert.ToSingle(Math.PI)) / 1000.0F
device.Transform.World = Matrix.RotationY(fAngle)
' Set up the view matrix. A view matrix can be defined given an eye point,
' a point to lookat, and a direction indicating which way is up. Here, you set
' the eye five units back along the z-axis and up three units, look at the
' origin, and define "up" to be in the y-direction.
device.Transform.View = Matrix.LookAtLH(New Vector3(0.0F, 3.0F, -5.0F), New Vector3(0.0F, 0.0F, 0.0F), New Vector3(0.0F, 1.0F, 0.0F))
' For the projection matrix, set up a perspective transform (which
' transforms geometry from 3-D view space to 2-D viewport space, with
' a perspective divide making objects smaller in the distance). To build
' a perspective transform, you need the field of view (1/4 PI is common),
' the aspect ratio, and the near and far clipping planes (which define
' the distances at which geometry should no longer be rendered).
device.Transform.Projection = Matrix.PerspectiveFovLH(System.Convert.ToSingle(Math.PI) / 4, 1.0F, 1.0F, 100.0F)
End Sub
``````
``````// This code example is from the Direct3D Mobile Matrices Sample
// in the .NET Compact Framework Samples in the SDK.
private void SetupMatrices()
{
// For the world matrix, rotate the object about the y-axis.

// Set up the rotation matrix to generate one full rotation (2*PI radians)
// every 1000 ms. To avoid the loss of precision inherent in very high
// floating-point numbers, the system time is modulated by the rotation
// period before conversion to a radian angle.
int iTime = Environment.TickCount % 1000;
float fAngle = iTime * (2.0f * (float)Math.PI) / 1000.0f;
device.Transform.World = Matrix.RotationY(fAngle);
// Set up the view matrix. A view matrix can be defined given an eye point,
// a point to look at, and a direction indicating which way is up. Here, you set
// the eye five units back along the z-axis and up three units, look at the
// origin, and define "up" to be in the y-direction.
device.Transform.View = Matrix.LookAtLH(new Vector3(0.0f, 3.0f, -5.0f), new Vector3(0.0f, 0.0f, 0.0f), new Vector3(0.0f, 1.0f, 0.0f));
// For the projection matrix, set up a perspective transform (which
// transforms geometry from 3-D view space to 2-D viewport space, with
// a perspective divide making objects smaller in the distance). To build
// a perspective transform, you need the field of view (1/4 PI is common),
// the aspect ratio, and the near and far clipping planes (which define
// the distances at which geometry should no longer be rendered).
device.Transform.Projection = Matrix.PerspectiveFovLH((float)Math.PI / 4, 1.0f, 1.0f, 100.0f);
}
``````

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

## Platforms

Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

## Version Information

#### .NET Compact Framework

Supported in: 3.5, 2.0

#### Reference

Matrix Members

Microsoft.WindowsMobile.DirectX Namespace

#### Other Resources

Mobile Direct3D Programming in the .NET Compact Framework