D3DXUVAtlasCreate function

Create a UV atlas for a mesh.

Syntax

HRESULT D3DXUVAtlasCreate(
  _In_        LPD3DXMESH      pMesh,
  _In_        UINT            dwMaxChartNumber,
  _In_        FLOAT           fMaxStretch,
  _In_        UINT            dwWidth,
  _In_        UINT            dwHeight,
  _In_        FLOAT           fGutter,
  _In_        DWORD           dwTextureIndex,
  _In_  const DWORD           *pdwAdjacency,
        const DWORD           *pdwFalseEdges,
  _In_        FLOAT           *pfIMTArray,
  _In_        LPD3DXUVATLASCB pCallback,
  _In_        FLOAT           fCallbackFrequency,
  _In_        LPVOID          pUserContext,
  _In_        DWORD           dwOptions,
  _In_        LPD3DXMESH      *ppMeshOut,
  _Out_       LPD3DXBUFFER    *ppFacePartitioning,
  _Out_       LPD3DXBUFFER    *ppVertexRemapArray,
  _Out_       FLOAT           *pfMaxStretchOut,
  _Out_       UINT            *pdwNumChartsOut
);

Parameters

pMesh [in]

Type: LPD3DXMESH

Pointer to an input mesh (see ID3DXMesh) which contains the object geometry for calculating the atlas. At a minimum, the mesh must contain position data and 2D texture coordinates.

dwMaxChartNumber [in]

Type: UINT

The maximum number of charts to partition the mesh into. See remarks about the partitioning modes. Use 0 to tell D3DX that the atlas should be parameterized based on stretch.

fMaxStretch [in]

Type: FLOAT

The amount of stretching allowed. 0 means no stretching is allowed, 1 means any amount of stretching can be used.

dwWidth [in]

Type: UINT

Texture width.

dwHeight [in]

Type: UINT

Texture height.

fGutter [in]

Type: FLOAT

The minimum distance, in texels, between two charts on the atlas. The gutter is always scaled by the width; so, if a gutter of 2.5 is used on a 512x512 texture, then the minimum distance between two charts is 2.5 / 512.0 texels.

dwTextureIndex [in]

Type: DWORD

Zero-based texture coordinate index that identifies which set of texture coordinates to use.

pdwAdjacency [in]

Type: const DWORD*

A pointer to an array of adjacency data. with 3 DWORDs per face, indicating which triangles are adjacent to each other (see ID3DXBaseMesh::GenerateAdjacency).

pdwFalseEdges

Type: const DWORD*

An array with 3 DWORDS per face. Each face indicates if an edge is false or not. A non-false edge is indicated by -1, a false edge is indicated by any other value. This enables the parameterization of a mesh of quads where the edges down the middle of each quad will not be cut.

pfIMTArray [in]

Type: FLOAT*

A pointer to an array of integrated metric tensors that describes how to stretch a triangle (see IntegratedMetricTensor).

pCallback [in]

Type: LPD3DXUVATLASCB

A pointer to a callback function (see LPD3DXUVATLASCB) that is useful for monitoring progress.

fCallbackFrequency [in]

Type: FLOAT

Specify how often D3DX will call the callback; a reasonable default value is 0.0001f.

pUserContent [in]

Type: LPVOID

Pointer to a user-defined value which is passed to the callback function; typically used by an application to pass a pointer to a data structure that provides context information for the callback function.

dwOptions [in]

Type: DWORD

Specify the quality of the charts generated. See D3DXUVATLAS.

ppMeshOut [in]

Type: LPD3DXMESH*

Pointer to the created mesh with the atlas (see ID3DXMesh).

ppFacePartitioning [out]

Type: LPD3DXBUFFER*

A pointer to an array of the final face-partitioning data. Each element contains one DWORD per face (see ID3DXBuffer).

ppVertexRemapArray [out]

Type: LPD3DXBUFFER*

A pointer to an array of remapped vertices. Each array element identifies the original vertex that each final vertex came from (if the vertex was split during remapping). Each array element contains one DWORD per vertex.

pfMaxStretchOut [out]

Type: FLOAT*

A pointer to the maximum stretch value generated by the atlas algorithm. The range is between 0.0 and 1.0.

pdwNumChartsOut [out]

Type: UINT*

A pointer to the number of charts created by the atlas algorithm. If dwMaxChartNumber is too low, this parameter will return the minimum number of charts required to create an atlas.

Return value

Type: HRESULT

If the function succeeds, the return value is D3D_OK; otherwise, the value is D3DERR_INVALIDCALL.

Remarks

D3DXUVAtlasCreate can partition mesh geometry two ways:

• Based on the number of charts
• Based on the maximum allowed stretch. If the maximum allowed stretch is 0, each triangle will likely be in its own chart.

Requirements

Requirement	Value
Header	D3DX9Mesh.h
Library	D3dx9.lib

See also

UVAtlas Functions

UV Atlas Command-Line Tool (uvatlas.exe)