WaveFrontReader

Utilities

This is a simple reader for WaveFront OBJ mesh data files used by meshconvert and uvatlas, as well as a few samples.

Header

#include "WaveFrontReader.h"

Namespace

The template class in this header is in the global C++ namespace.

Template class

template<class index_t> class WaveFrontReader;

Methods

• Load: Loads the given WaveFront OBJ file into the reader instance. If the parameter ccw is true (the default), then the face-winding is flipped. This is useful for dealing with models designed for left/right-handed view, but the rendering is using the opposite.

• LoadMTL: This loads the mtl material file associated with the WaveFront OBJ file. This method is invoked if the mtllib element is found in the OBJ file.

• Clear: This clears all data from the instance.

• LoadVBO: This loads a vbo binary file (a simple format created for samples) into the instance. This creates a since default material since vbo contains only an IB (16-bit) and a VB.

Member variables

• vertices: This is a vector of Vertex instances. See remarks for details.

• indices: A vector of indices which is 3 * the number of faces in length.

• attributes: A vector with one entry for each face indicating the material.

• materials: A Vector of Material information. See remarks for details.

• name: This is set to the root filename of the loaded file (if any).

• bounds: Bounding box of vertex locations computed by the loader.

Remarks

Vertex data is limited to the following structure (hasNormals and hasTexcoords member variables indicate if the relevant vertex data is valid):

struct Vertex
{
    DirectX::XMFLOAT3 position;
    DirectX::XMFLOAT3 normal;
    DirectX::XMFLOAT2 textureCoordinate;
};

This reader returns all vertex/index data as a single object as it ignores the g group name elements. All polygons are triangulated.

The WaveFrontReader supports both 16-bit and 32-bit indices via a C++ template:

WaveFrontReader<uint16_t> wfReader;

HRESULT hr = wfReader.Load(L"cup.obj");
if (FAILED(hr))

WaveFrontReader<uint32_t> wfReader;

HRESULT hr = wfReader.Load(L"cup.obj");
if (FAILED(hr))

The attributes member provides the material index for each triangular face in the loaded mesh. Materials data is returned in the following structure. The materials file parsing supports a few 'unofficial extensions': Ke, map_Ks, map_Ke, map_RMA, map_ORM.

struct Material
{
    DirectX::XMFLOAT3 vAmbient;    // Ka
    DirectX::XMFLOAT3 vDiffuse;    // Kd
    DirectX::XMFLOAT3 vSpecular;   // Ks
    DirectX::XMFLOAT3 vEmissive;   // Ke
    uint32_t nShininess;           // Ns
    float fAlpha;                  // d or Tr

    bool bSpecular;                // True if illum=2
    bool bEmissive;                // True if Ke or map_Ke was found

    wchar_t strName[MAX_PATH];             // newmtl
    wchar_t strTexture[MAX_PATH];          // map_Kd
    wchar_t strNormalTexture[MAX_PATH];    // map_Kn
    wchar_t strSpecularTexture[MAX_PATH];  // map_Ks
    wchar_t strEmissiveTexture[MAX_PATH];  // map_Ke
    wchar_t strRMATexture[MAX_PATH];       // map_RMA or map_ORM
};

The original code for the reader was created for the MeshFromOBJ legacy DirectX SDK sample DX9 / DX10.