DirectX9 creating vertex and Index caches

C + + create vertex and index caches

A vertex buffer is simply a chunk of contiguous memory, that contains vertex data. Similarly, an index buffer was a chunk of contiguous memory that contains index data.

We can create a vertex and index buffer with the following and the methods:

HRESULT Idirect3ddevice9::createvertexbuffer (
UINT Length,
DWORD Usage,
DWORD FVF,
D3dpool Pool
idirect3dvertexbuffer9** Ppvertexbuffer,
handle* Psharedhandle
);

HRESULT Idirect3ddevice9::createindexbuffer (
UINT Length,
DWORD Usage,
D3dformat Format,
D3dpool Pool,
idirect3dindexbuffer9** Ppindexbuffer,
handle* Psharedhandle
);

The majority of the parameters is identical for both methods, so let's cover the parameters of both methods together.

Length-the number of bytes to allocate for the buffer. If we wanted a vertex buffer to the enough memory to store eight vertices, we would set this parameter To8 * sizeof (verte x), Wherevertexis our vertex structure.

Usage-specifies some additional properties about what the buffer is used. This value can is zero, indicating no additional properties, or a combination of one or more of the following flags:

D3dusage_dynamic-setting This flag makes the bufferdynamic. See the notes in static and dynamic buffers on the following page.
D3dusage_points-this flag specifies that the buffer would hold point primitives. Point primitives is covered in "particle Systems" in Chapter 14. This flag was used only for vertex buffers.
D3dusage_softwareprocessing-vertex processing is do in software.
D3dusage_writeonly-specifies that the application would only write to the buffer. This allows the driver-place the buffer in the best memory location for write operations. Note that reading from a buffer created with the this flag would result in an error.

Fvf-the flexible vertex format of the vertices that's stored in the vertex buffer

Pool-the memory pool in which the buffer is placed

Ppvertexbuffer-pointer to receive the created vertex buffer

Psharedhandle-not used; Set to zero

Format-specifies the size of the indices; used3dfmt_index16 for 16-bit indices or used3dfmt_index32for 32-bit indices. Note that the devices support 32-bit indices; Check the device capabilities.

Ppindexbuffer-pointer to receive the created index buffer

The following example creates a static vertex buffer that have enough memory to hold eight vertices of typevertex.

idirect3dvertexbuffer9* vb;
_device->createvertexbuffer (
8 * sizeof (VERTEX),
0,
D3DFVF_XYZ,
D3dpool_managed,

&VB,

0);

This next code example shows what to create a dynamic index of buffer that have enough memory to hold the 16-bit indices.

Idirect3dindexbuffer9* IB;
_device->createindexbuffer (
$ * sizeof (WORD),
D3dusage_dynamic | D3dusage_writeonly,
d3dfmt_index16,
d3dpool_managed,
&ib,
0);