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IndexBuffer.Lock(Int32,Int32,LockFlags) Method (Microsoft.DirectX.Direct3D)

  • Article

How Do I...?

  • Create a Mesh Object

Locks a range of index data and obtains a pointer to the index buffer memory.

Definition

Visual Basic Public Function Lock( _
    ByVal offsetToLock As Integer, _
    ByVal sizeToLock As Integer, _
    ByVal flags As LockFlags _
) As GraphicsStream
C# public GraphicsStream Lock(
    int offsetToLock,
    int sizeToLock,
    LockFlags flags
);
C++ public:
GraphicsStream^ Lock(
    int offsetToLock,
    int sizeToLock,
    LockFlags flags
);
JScript public function Lock(
    offsetToLock : int,
    sizeToLock : int,
    flags : LockFlags
) : GraphicsStream;

Parameters

offsetToLock System.Int32
Offset into the index data to lock, in bytes. To lock the entire index buffer, specify 0 for the param_Int32_sizeToLock and param_Int32_offsetToLock parameters.
sizeToLock System.Int32
Size of the index data to lock, in bytes. To lock the entire index buffer, specify 0 for the param_Int32_sizeToLock and param_Int32_offsetToLock parameters.
flags Microsoft.DirectX.Direct3D.LockFlags
Zero or more LockFlags that describe the type of lock to perform. For this method, the valid flags are Discard, NoDirtyUpdate, NoSystemLock, NoOverwrite, and ReadOnly.

Return Value

Microsoft.DirectX.GraphicsStream
A GraphicsStream object that represents the locked index buffer.

Remarks

When working with index buffers, multiple lock calls are allowed. However, the number of lock calls must match the number of unlock calls. None of the DrawPrimitives calls will succeed with any outstanding lock count on any currently set index buffer.

The Lock.Discard and NoOverWrite flags are valid only on buffers created with Dynamic.

Exceptions

InvalidCallException

The method call is invalid. For example, a method's parameter might contain an invalid value.

How Do I...?

Create a Mesh Object

This example shows how to create a Mesh object.

In the following C# code example, device is assumed to be the rendering Device.

              [C#]
              
int numberVerts = 8;
short[] indices = {
    0,1,2, // Front Face 
    1,3,2, // Front Face 
    4,5,6, // Back Face 
    6,5,7, // Back Face 
    0,5,4, // Top Face 
    0,2,5, // Top Face 
    1,6,7, // Bottom Face 
    1,7,3, // Bottom Face 
    0,6,1, // Left Face 
    4,6,0, // Left Face 
    2,3,7, // Right Face 
    5,2,7 // Right Face 
};

Mesh mesh = new Mesh(numberVerts * 3, numberVerts, MeshFlags.Managed,
                     CustomVertex.PositionColored.Format, device);

using(VertexBuffer vb = mesh.VertexBuffer)
{
    GraphicsStream data = vb.Lock(0, 0, LockFlags.None);

    data.Write(new CustomVertex.PositionColored(-1.0f, 1.0f, 1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(-1.0f, -1.0f, 1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(1.0f, 1.0f, 1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(1.0f, -1.0f, 1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(-1.0f, 1.0f, -1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(1.0f, 1.0f, -1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(-1.0f, -1.0f, -1.0f, 0x00ff00ff));
    data.Write(new CustomVertex.PositionColored(1.0f, -1.0f, -1.0f, 0x00ff00ff));

    vb.Unlock();
}

using (IndexBuffer ib = mesh.IndexBuffer)
{
    ib.SetData(indices, 0, LockFlags.None);
}

See Also