IDirect3DDevice9::DrawTriPatch method (d3d9helper.h)

Draws a triangular patch using the currently set streams.

Syntax

HRESULT DrawTriPatch(
  [in] UINT                   Handle,
  [in] const float            *pNumSegs,
  [in] const D3DTRIPATCH_INFO *pTriPatchInfo
);

Parameters

[in] Handle

Type: UINT

Handle to the triangular patch to draw.

[in] pNumSegs

Type: const float*

Pointer to an array of three floating-point values that identify the number of segments each edge of the triangle patch should be divided into when tessellated. See D3DTRIPATCH_INFO.

[in] pTriPatchInfo

Type: const D3DTRIPATCH_INFO*

Pointer to a D3DTRIPATCH_INFO structure, describing the triangular high-order patch to draw.

Return value

Type: HRESULT

If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be D3DERR_INVALIDCALL.

Remarks

For static patches: Set the vertex shader, set the appropriate streams, supply patch information in the pTriPatchInfo parameter, and specify a handle so that Direct3D can capture and cache information. To efficiently draw the patch, call IDirect3DDevice9::DrawTriPatch with pTriPatchInfo set to NULL. When drawing a cached patch, the currently set streams are ignored. Override the cached pNumSegs by specifying a new value for pNumSegs. When rendering a cached patch, you must set the same vertex shader that was set when it was captured.

Calling IDirect3DDevice9::DrawTriPatch with a handle invalidates the same handle cached by a previous IDirect3DDevice9::DrawRectPatch call.

For dynamic patches, the patch data changes for every rendering of the patch so it is not efficient to cache information. The application can convey this to Direct3D by setting Handle to 0. In this case, Direct3D draws the patch using the currently set streams and the pNumSegs values, and does not cache any information. It is not valid to simultaneously set Handle to 0 and pTriPatchInfo to NULL.

Requirements

See also

IDirect3DDevice9

Using Higher-Order Primitives (Direct3D 9)