CODEWITHSUNDEEP
meshdirect3d
Salmon
Salmon

Reputation: 73

D3D, Vertex From Mesh

By Using D3DXLoadMeshFromX, I could load a mesh's subsets, materials, textures,... So I succeed Draw Mesh.

What I want to know is that Mesh's Vertex Infomation(for picking).

My Code is..

    m_pMesh->PDIRECT3DVERTEXBUFFER9     pVB;
    m_pMesh->GetVertexBuffer(&pVB);

    void* Vtx = nullptr;
    pVB->Lock(0, 0, (void**)&Vtx, 0);

Then I want to know Vtx's information like Vertex, but Vtx is void pointer... If I know struct of that mesh I might know vertex info, but I don't

I'm sorry if I answer too vaguely.

Upvotes: 0

Views: 187

Answers (1)

Chuck Walbourn
Chuck Walbourn

Reputation: 41127

This is covered in the legacy DirectX SDK's sample in Samples\C++\Direct3D\Pick.

You have to use CloneMeshFVF to reformat the vertex data layout and you need to make sure you specify D3DXMESH_VB_MANAGED or D3DXMESH_VB_SYSTEMMEM so that you can actually lock the resulting VB.

   LPD3DXMESH pMesh;

    g_Mesh.GetMesh()->CloneMeshFVF( D3DXMESH_MANAGED,
                                    g_Mesh.GetMesh()->GetFVF(), pD3Device, &pMesh );

    LPDIRECT3DVERTEXBUFFER9 pVB;
    LPDIRECT3DINDEXBUFFER9 pIB;

    pMesh->GetVertexBuffer( &pVB );
    pMesh->GetIndexBuffer( &pIB );

    WORD* pIndices;
    D3DVERTEX* pVertices;

    pIB->Lock( 0, 0, ( void** )&pIndices, 0 );
    pVB->Lock( 0, 0, ( void** )&pVertices, 0 );

Keep in mind that picking uses a CPU memory copy of the vertex data, while rendering uses a video memory copy. In real-time applications, you typically do not use the full complexity of the rendering model for collision, but a simplified collision model that you never need to render and only keep in memory.

Upvotes: 1

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