Applications written in Microsoft® Visual Basic® can create a projection matrix as described in the What Is the Projection Transformation? topic. However, the Direct3DX utility library provides the following functions to help you set up your projections matrix.

• D3DXMatrixPerspectiveLH
• D3DXMatrixPerspectiveRH
• D3DXMatrixPerspectiveFovLH
• D3DXMatrixPerspectiveFovRH
• D3DXMatrixPerspectiveOffCenterLH
• D3DXMatrixPerspectiveOffCenterRH

The following Visual Basic code example shows how D3DXMatrixPerspectiveLH is commonly used.

    ' This example assumes that g_D3DDevice is a valid reference 
    ' to a Direct3DDevice8 object. 

    ' 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 that makes 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 be no longer be rendered.

    Dim matProj As D3DMATRIX

    D3DXMatrixPerspectiveFovLH matProj, g_pi / 4, 1, 1, 1000
    g_D3DDevice.SetTransform D3DTS_PROJECTION, matProj

After you create the matrix, you must set it in a call to the Direct3DDevice8.SetTransform method, specifying D3DTRANSFORMSTATE_PROJECTION in the first parameter. For details, see Setting Transformations.