D3DHAL_DP2TRIANGLEFAN structure

One D3DHAL_DP2TRIANGLEFAN structure is parsed from the command buffer by the D3dDrawPrimitives2 callback when the D3DHAL_DP2COMMAND structure's bCommand member is set to D3DDP2OP_TRIANGLEFAN, and is used to render a triangle fan.

Syntax


typedef struct _D3DHAL_DP2TRIANGLEFAN {
  WORD wVStart;
} D3DHAL_DP2TRIANGLEFAN, *LPD3DHAL_DP2TRIANGLEFAN;

Members

wVStart

Specifies the index into the vertex buffer containing coordinate data for the initial vertex of the triangle fan.

Remarks

One D3DHAL_DP2TRIANGLEFAN structure follows the D3DHAL_DP2COMMAND structure in the command buffer.

D3dDrawPrimitives2 should process a total of wPrimitiveCount + 2 vertices from the vertex buffer, three vertices per triangle, rendering wPrimitiveCount triangles. Starting from the vertex buffer offset, the sequence of triangles rendered is (wVStart + 1, wVStart + 2, wVStart ), (wVStart + 2, wVStart + 3, wVStart ),..., (wVStart + wPrimitiveCount, wVStart +wPrimitiveCount + 1, wVStart ). The value of wPrimitiveCount is specified in the D3DHAL_DP2COMMAND structure.

The following figure shows a portion of a sample command buffer containing a D3DDP2OP_TRIANGLEFAN command and a D3DHAL_DP2TRIANGLEFAN structure. The driver should process six vertices from the vertex buffer, rendering a fan with four triangles defined by (v[3], v[4], v[2]), (v[4], v[5], v[2]), (v[5], v[6], v[2]), (v[6], v[7], v[2]).

Figure showing a command buffer with a D3DDP2OP_TRIANGLEFAN command and a D3DHAL_DP2TRIANGLEFAN structure

Requirements

Header

D3dhal.h (include D3dhal.h)

See also

D3DDP2OP_TRIANGLEFAN
D3dDrawPrimitives2
D3DHAL_DP2COMMAND

 

 

Send comments about this topic to Microsoft

Show: