c++ - How to read in FBX 2014 indices properly for DirectX? -

i've been having annoying problem past weekend. have able to read in triangulated 2014 fbx file contains mesh exported maya , read in it's vertices , indices passed renderer (directx) drawindexed call.

so way have setup there tuniquevertex structure

struct tuniquevertex {     xmfloat3 m_vposition,   // vertex positions     xmfloat3 m_vnormal,     // vertex normals     xmfloat2 m_uvs          // vertex uvs     int m_ncontrolpointindex, // control point index  } 

this code here, load in fbxmesh cmesh class. holds mesh's vertices , indices.

 class cmesh  {      ...     vector<tuniquevertex> m_vvertices;     vector<unsigned int> m_vindices;  } 

the code load cmesh:

bool loadmesh(fbxmesh* pmesh, cmesh cmesh) {     int polygoncount = pmesh->getpolygoncount();             fbxvector4* controlpoints = pmesh->getcontrolpoints();     int controlpointcount = pmesh->getcontrolpointscount();      int vertexid = 0;      (int polygon = 0; polygon < polygoncount; polygon++)     {         int polyvertcount = pmesh->getpolygonsize(polygon);      (int polyvert = 0; polyvert < polyvertcount; polyvert++)     {         cmesh::tuniquevertex uniquevert;          int cpindex = pmesh->getpolygonvertex(polygon, polyvert);          // grab our cp index our position information         uniquevert.m_ncontrolpointindex = cpindex;         uniquevert.m_vposition =          xmfloat3((float)controlpoints[cpindex].mdata[0],                  (float)controlpoints[cpindex].mdata[1],                  (float)controlpoints[cpindex].mdata[2]);          // grab uvs         int uvelementcount = pmesh->getelementuvcount();          (int uvelement = 0; uvelement < uvelementcount; uvelement++)         {             fbxgeometryelementuv* geomelementuv = pmesh>getelementuv(uvelement);              fbxlayerelement::emappingmode mapmode = geomelementuv->getmappingmode();             fbxlayerelement::ereferencemode refmode = geomelementuv->getreferencemode();              int directindex = -1;              if (fbxgeometryelement::ebycontrolpoint == mapmode)             {                 if (fbxgeometryelement::edirect == refmode)                 {                     directindex = cpindex;                 }                 else if (fbxgeometryelement::eindextodirect == refmode)                 {                     directindex = geomelementuv->getindexarray().getat(cpindex);                 }             }             else if (fbxgeometryelement::ebypolygonvertex == mapmode)             {                 if (fbxgeometryelement::edirect == refmode || fbxgeometryelement::eindextodirect == refmode)                 {                     directindex = pmesh->gettextureuvindex(polygon, polyvert);                 }              }              // if got uv index             if (directindex != -1)             {                 fbxvector2 uv = geomelementuv->getdirectarray().getat(directindex);                  uniquevert.m_uvs = xmfloat2( (float)uv.mdata[0],                                              (float)uv.mdata[1]);             }         }          // grab normals         int normelementcount = pmesh->getelementnormalcount();          (int normelement = 0; normelement < normelementcount; normelement++)         {             fbxgeometryelementnormal* geomelementnormal = pmesh->getelementnormal(normelement);              fbxlayerelement::emappingmode mapmode = geomelementnormal->getmappingmode();             fbxlayerelement::ereferencemode refmode = geomelementnormal->getreferencemode();              int directindex = -1;              if (fbxgeometryelement::ebypolygonvertex == mapmode)             {                 if (fbxgeometryelement::edirect == refmode)                 {                     directindex = vertexid;                 }                 else if (fbxgeometryelement::eindextodirect == refmode)                 {                     directindex = geomelementnormal->getindexarray().getat(vertexid);                 }             }              // if got index             if (directindex != 1)             {                 fbxvector4 norm = geomelementnormal->getdirectarray().getat(directindex);                  uniquevert.m_vnormal = xmfloat3((float)norm.mdata[0],                                                 (float)norm.mdata[1],                                                 (float)norm.mdata[2]);              }         }          // unique vertices stuff         vector<cmesh::tuniquevertex>& uniqueverts = cmesh.getvertices();          size_t size = uniqueverts.size();         size_t i;          (i = 0; < size; i++)         {             if (uniquevert == uniqueverts[i])             {                 break;             }         }          if (i == size)         {             uniqueverts.push_back(uniquevert);         }          cmesh.getindices().push_back(i);         ++vertexid;     } }  return true; } 

doing method loads in vertices, normals, , uvs correctly. however, when loading in indices , passing cmesh.getindices() count drawindexed call, indices out of order , looks in graphic debugger:

incase wondering, indices follows:

012, 023, 456, 657, 891, 081, 011, 121, 314, 121, 415, 161, 718, 171, 918, 202, 122, 212, 023

and here test .fbx i'm trying load information from:

cube.fbx direct download

if can me out this, i'd extremely grateful issue has caused me stress :d

are using left-handed view coordinates or right-handed view coordinates in application (see link)? if using left-handed view coordinates, need flip winding of each triangle in index buffer.

    assert( (indices.size() % 3) == 0 );     for( auto = indices.begin(); != indices.end(); += 3 )     {         std::swap( *it, *(it+2) );     } 

you may need flip texture coordinates well:

    for( auto = vertices.begin(); != vertices.end(); ++it )     {         it->texturecoordinate.x = ( 1.f - it->texturecoordinate.x );     } 

historically directx applications use left-handed view coordinates. xna game studio , opengl applications use right-handed view coordinates.

btw, why both -fliptriangles+ , -invertvtexcoord+ enabled default in samples content exporter sdkmesh.