移植DXUT SDKMesh导入OBJ文件，在哪里添加纹理坐标和索引？

Question

下午好，

我已经成功移植 DXUT SDKMesh 以通过 TinyOBJ 加载程序加载导入的 obj 文件https://github.com/syoyo/tinyobjloader) 以使用正确的索引值绘制网格。

我还添加了一个作为 DDS 加载的纹理 material

它当前正在绘制网格，但整个纹理在每个三角形上都被拉伸

我现在需要弄清楚在哪里添加纹理坐标，以及这些纹理坐标的索引。

代码重构自DXUT SDKMesh CDXUTSDKMesh::CreateFromMemory函数。 SDKMesh代码比较大，不过可以参考这里http://freesourcecode.net/cprojects/92957/sourcecode/SDKmesh.cpp

如您所见，我正在使用 InitData.pSysMem = &vertex_buffer[0];

加载顶点列表

索引列表使用InitData2.pSysMem = &index_buffer[0];

DXUT SDKMesh 对二进制 .sdkmesh 文件做同样的事情我同时加载 DXUT 示例模型 tiny.sdkmesh。它们都使用相同的着色器和渲染函数进行渲染。所以我知道问题不在于渲染函数，而在于我构建顶点和索引缓冲区的方式。

我需要知道的是这些顶点和索引缓冲区是如何构造的。和我知道这是由顶点着色器决定的，虽然我不完全知道如何。

顶点着色器有这些输入和输出：

struct VS_INPUT
{
float4 vPosition    : POSITION;
float3 vNormal      : NORMAL;
float2 vTexcoord    : TEXCOORD0;
};

struct VS_OUTPUT
{
float3 vNormal      : NORMAL;
float2 vTexcoord    : TEXCOORD0;
float4 vPosition    : SV_POSITION;
};

如果我将值保留为现在的注释，它就可以工作。如果我添加它们，它会破坏模型。

我不明白的是如何将顶点和纹理坐标分组到一个缓冲区中，以及如何将 vertex_index 和 texcoord_index 分组到另一个缓冲区中。以及如何将其分解并加载为顶点着色器输入。（如果它甚至以这种方式使用）。

我试着按顺序添加它们，一个接一个，等等，在每一种情况下都破坏了模型。

如果您对如何正确地将它们组合在一起有任何建议或教育，我们将不胜感激。谢谢，

//Need to sort indices and vertices from TinyOBJ loader
std::vector<float> vertex_buffer;
for (int i = 0; i < num_vertices/3; i++)
{
    vertex_buffer.push_back(attrib.vertices[i * 3 + 0]);
    vertex_buffer.push_back(attrib.vertices[i * 3 + 1]);
    vertex_buffer.push_back(attrib.vertices[i * 3 + 2]);
    //vertex_buffer.push_back(attrib.texcoords[i * 2 + 0]);
    //vertex_buffer.push_back(attrib.texcoords[i * 2 + 1]);
    //vertex_buffer.push_back(0);
}

std::vector<UINT> index_buffer;
for (int i = 0; i < num_indices/3; i++)
{
    index_buffer.push_back(shapes[0].mesh.indices[i * 3 + 0].vertex_index);
    index_buffer.push_back(shapes[0].mesh.indices[i * 3 + 1].vertex_index);
    index_buffer.push_back(shapes[0].mesh.indices[i * 3 + 2].vertex_index);
    //index_buffer.push_back(shapes[0].mesh.indices[i * 2 + 0].texcoord_index);
    //index_buffer.push_back(shapes[0].mesh.indices[i * 2 + 1].texcoord_index);
    //index_buffer.push_back(0);
}

g_Mesh11.m_ppVertices = (BYTE**)&vertex_buffer;
g_Mesh11.m_ppIndices = (BYTE**)&index_buffer;

//Magic Numbers that make it use every vertex and index
int vertexes_size = (vertex_buffer.size()) * sizeof(float) *1.5F;
int indexes_size = shapes[0].mesh.indices.size() * sizeof(UINT) *3;

//Set Vertex Buffer Array
g_Mesh11.m_pMeshArray = new SDKMESH_MESH;
g_Mesh11.m_pVertexBufferArray = new SDKMESH_VERTEX_BUFFER_HEADER;
g_Mesh11.m_pMeshArray[0].VertexBuffers[0] = 0;
D3D11_BUFFER_DESC bufferDesc;
bufferDesc.ByteWidth = (UINT)(vertexes_size);
bufferDesc.Usage = D3D11_USAGE_DEFAULT;
bufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
bufferDesc.CPUAccessFlags = 0;
bufferDesc.MiscFlags = 0;
D3D11_SUBRESOURCE_DATA InitData;
InitData.pSysMem = &attrib.vertices[0];
dxCtr->m_pDevice->CreateBuffer(&bufferDesc, &InitData, &g_Mesh11.m_pVertexBufferArray[g_Mesh11.m_pMeshArray[0].VertexBuffers[0]].pVB11);
g_Mesh11.m_pVertexBufferArray[g_Mesh11.m_pMeshArray[0].VertexBuffers[0]].StrideBytes = 12;
g_Mesh11.m_pVertexBufferArray[g_Mesh11.m_pMeshArray[0].VertexBuffers[0]].SizeBytes = vertexes_size;

//Set Index Buffer array
g_Mesh11.m_pMeshArray[0].IndexBuffer = 0;
g_Mesh11.m_pIndexBufferArray = new SDKMESH_INDEX_BUFFER_HEADER;
g_Mesh11.m_pIndexBufferArray[g_Mesh11.m_pMeshArray[0].IndexBuffer].IndexType = IT_32BIT;
D3D11_BUFFER_DESC bufferDesc2;
bufferDesc2.ByteWidth = (UINT)(indexes_size);
bufferDesc2.Usage = D3D11_USAGE_DEFAULT;
bufferDesc2.BindFlags = D3D11_BIND_INDEX_BUFFER;
bufferDesc2.CPUAccessFlags = 0;
bufferDesc2.MiscFlags = 0;
D3D11_SUBRESOURCE_DATA InitData2;
InitData2.pSysMem = &index_buffer[0]; 
dxCtr->m_pDevice->CreateBuffer(&bufferDesc, &InitData2, &g_Mesh11.m_pIndexBufferArray[g_Mesh11.m_pMeshArray[0].IndexBuffer].pIB11);
g_Mesh11.m_pIndexBufferArray[g_Mesh11.m_pMeshArray[0].IndexBuffer].SizeBytes = indexes_size;

//Set subset
SDKMESH_SUBSET v_subset;
//v_subset.Name = "Base";
v_subset.MaterialID = 0;
v_subset.PrimitiveType = PT_TRIANGLE_LIST;
v_subset.IndexCount = num_indices;
v_subset.VertexCount = num_vertices;
v_subset.VertexStart = 0;
v_subset.IndexStart = 0;
g_Mesh11.m_pMeshArray[0].pSubsets = new UINT;
g_Mesh11.m_pMeshArray[0].pSubsets[0] = 0;
g_Mesh11.m_pMeshArray[0].NumSubsets = 1;
g_Mesh11.m_pSubsetArray = new SDKMESH_SUBSET;
g_Mesh11.m_pSubsetArray[g_Mesh11.m_pMeshArray[0].pSubsets[0]] = v_subset;

Answer 1

解决方案是将数据交织到一个顶点缓冲区中。这可能需要复制顶点，比如位置相同，但纹理坐标或法线不同。

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

typedef std::unordered_multimap<UINT, UINT> VertexCache;

DWORD AddVertex(UINT hash, Vertex* pVertex, VertexCache& cache)
{
    auto f = cache.equal_range(hash);

    for (auto it = f.first; it != f.second; ++it)
    {
        auto& tv = vertices[it->second];

        if (0 == memcmp(pVertex, &tv, sizeof(Vertex)))
        {
            return it->second;
        }
    }

    DWORD index = static_cast<UINT>(vertices.size());
    vertices.emplace_back(*pVertex);

    VertexCache::value_type entry(hash, index);
    cache.insert(entry);
    return index;
}

可以这样使用：

// If a duplicate vertex doesn't exist, add this vertex to the Vertices
// list. Store the index in the Indices array. The Vertices and Indices
// lists will eventually become the Vertex Buffer and Index Buffer for
// the mesh.
DWORD index = AddVertex(vertexIndex, &vertex, vertexCache);

有关完整实施，请参阅 WaveFrontReader.h and meshconvert that come with the DirectXMesh 库。

Answer 2

好的，我修好了，我不知道为什么会这样，但是

Texcoords 的索引缓冲区必须为 0

bool LoadOBJ(std::string object_file)
{
    TinyObjLoader::LoadOBJ(object_file);

    g_Mesh11.m_pMaterialArray = new SDKMESH_MATERIAL;
    std::wstring strPath = L"Media\Base_skin.dds";
    if (FAILED(DXUTGetGlobalResourceCache().CreateTextureFromFile(dxCtr->m_pDevice, dxCtr->m_pImmediateContext, strPath.c_str(), &g_Mesh11.m_pMaterialArray->pDiffuseRV11,true)))
        g_Mesh11.m_pMaterialArray->pDiffuseRV11 = (ID3D11ShaderResourceView*)ERROR_RESOURCE_VALUE;

    SDKMESH_SUBSET* pSubset = nullptr;
    D3D11_PRIMITIVE_TOPOLOGY PrimType;

    struct T_Vertex
    {
        float vX;
        float vY;
        float vZ;
        float nX;
        float nY;
        float nZ;
        float tX;
        float tY;
        UINT vXIndex;
        UINT vYIndex;
        UINT vZIndex;
        UINT nXIndex;
        UINT nYIndex;
        UINT nZIndex;
        UINT tXIndex;
        UINT tYIndex;
    };

    std::vector<T_Vertex> temp_vertices;
    size_t index_offset = 0;
    for (size_t f = 0; f < shapes[0].mesh.num_face_vertices.size(); f++) {
        int fv = shapes[0].mesh.num_face_vertices[f];
        // Loop over vertices in the face.
        for (size_t v = 0; v < fv; v++) {
            // access to vertex
            tinyobj::index_t idx = shapes[0].mesh.indices[index_offset + v];
            T_Vertex temp_vertex;
            temp_vertex.vX = attrib.vertices[3 * idx.vertex_index + 0];
            temp_vertex.vY = attrib.vertices[3 * idx.vertex_index + 1];
            temp_vertex.vZ = attrib.vertices[3 * idx.vertex_index + 2];
            temp_vertex.nX = attrib.normals[3 * idx.normal_index + 0];
            temp_vertex.nY = attrib.normals[3 * idx.normal_index + 1];
            temp_vertex.nZ = attrib.normals[3 * idx.normal_index + 2];
            temp_vertex.tX = attrib.texcoords[2 * idx.texcoord_index + 0];
            temp_vertex.tY = attrib.texcoords[2 * idx.texcoord_index + 1];
            temp_vertex.vXIndex = 3 * idx.vertex_index + 0;
            temp_vertex.vYIndex = 3 * idx.vertex_index + 1;
            temp_vertex.vZIndex = 3 * idx.vertex_index + 2;
            temp_vertex.nXIndex = 3 * idx.normal_index + 0;
            temp_vertex.nYIndex = 3 * idx.normal_index + 1;
            temp_vertex.nZIndex = 3 * idx.normal_index + 2;
            temp_vertex.tXIndex = 3 * idx.texcoord_index + 0;
            temp_vertex.tYIndex = 3 * idx.texcoord_index + 1;
            temp_vertices.push_back(temp_vertex);
        }
        index_offset += fv;
    }

    std::vector<float> vertex_buffer;
    std::vector<UINT> index_buffer;

    for (auto& temp_vertex : temp_vertices)
    {
        vertex_buffer.push_back(temp_vertex.vX);
        vertex_buffer.push_back(temp_vertex.vY);
        vertex_buffer.push_back(temp_vertex.vZ);
        vertex_buffer.push_back(temp_vertex.nX);
        vertex_buffer.push_back(temp_vertex.nY);
        vertex_buffer.push_back(temp_vertex.nZ);
        vertex_buffer.push_back(temp_vertex.tX);
        vertex_buffer.push_back(temp_vertex.tY);
        vertex_buffer.push_back(0);

        index_buffer.push_back(temp_vertex.vXIndex);
        index_buffer.push_back(temp_vertex.vYIndex);
        index_buffer.push_back(temp_vertex.vZIndex);
        index_buffer.push_back(temp_vertex.nXIndex);
        index_buffer.push_back(temp_vertex.nYIndex);
        index_buffer.push_back(temp_vertex.nZIndex);
        index_buffer.push_back(0);
        index_buffer.push_back(0);
        index_buffer.push_back(0);
    }

    int num_vertices = vertex_buffer.size();
    int num_indices = index_buffer.size();

    g_Mesh11.m_ppVertices = (BYTE**)&vertex_buffer;
    g_Mesh11.m_ppIndices = (BYTE**)&index_buffer;

    int vertexes_size = vertex_buffer.size() * sizeof(float);       int indexes_size = index_buffer.size() * sizeof(UINT);  
    //Set Vertex Buffer Array
    g_Mesh11.m_pMeshArray = new SDKMESH_MESH;
    g_Mesh11.m_pVertexBufferArray = new SDKMESH_VERTEX_BUFFER_HEADER;
    int t = g_Mesh11.m_pMeshArray[0].VertexBuffers[0];
    g_Mesh11.m_pMeshArray[0].VertexBuffers[0] = 0;
    D3D11_BUFFER_DESC bufferDesc;
    bufferDesc.ByteWidth = (UINT)(vertexes_size);
    bufferDesc.Usage = D3D11_USAGE_DEFAULT;
    bufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
    bufferDesc.CPUAccessFlags = 0;
    bufferDesc.MiscFlags = 0;
    D3D11_SUBRESOURCE_DATA InitData;
    InitData.pSysMem = &vertex_buffer[0];
    dxCtr->m_pDevice->CreateBuffer(&bufferDesc, &InitData, &g_Mesh11.m_pVertexBufferArray[g_Mesh11.m_pMeshArray[0].VertexBuffers[0]].pVB11);
    g_Mesh11.m_pVertexBufferArray[g_Mesh11.m_pMeshArray[0].VertexBuffers[0]].StrideBytes = 36;// 12;
    g_Mesh11.m_pVertexBufferArray[g_Mesh11.m_pMeshArray[0].VertexBuffers[0]].SizeBytes = vertexes_size;

    //Set Index Buffer array
    g_Mesh11.m_pMeshArray[0].IndexBuffer = 0;
    g_Mesh11.m_pIndexBufferArray = new SDKMESH_INDEX_BUFFER_HEADER;
    g_Mesh11.m_pIndexBufferArray[g_Mesh11.m_pMeshArray[0].IndexBuffer].IndexType = IT_32BIT;
    D3D11_BUFFER_DESC bufferDesc2;
    bufferDesc2.ByteWidth = (UINT)(indexes_size);
    bufferDesc2.Usage = D3D11_USAGE_DEFAULT;
    bufferDesc2.BindFlags = D3D11_BIND_INDEX_BUFFER;
    bufferDesc2.CPUAccessFlags = 0;
    bufferDesc2.MiscFlags = 0;
    D3D11_SUBRESOURCE_DATA InitData2;
    InitData2.pSysMem = &index_buffer[0];
    dxCtr->m_pDevice->CreateBuffer(&bufferDesc2, &InitData2, &g_Mesh11.m_pIndexBufferArray[g_Mesh11.m_pMeshArray[0].IndexBuffer].pIB11);
    g_Mesh11.m_pIndexBufferArray[g_Mesh11.m_pMeshArray[0].IndexBuffer].SizeBytes = indexes_size;

    //Set subset
    SDKMESH_SUBSET v_subset;
    v_subset.MaterialID = 0;
    v_subset.PrimitiveType = PT_TRIANGLE_LIST;
    v_subset.IndexCount = num_indices;
    v_subset.VertexCount = num_vertices;
    v_subset.VertexStart = 0;
    v_subset.IndexStart = 0;
    g_Mesh11.m_pMeshArray[0].pSubsets = new UINT;
    g_Mesh11.m_pMeshArray[0].pSubsets[0] = 0;
    g_Mesh11.m_pMeshArray[0].NumSubsets = 1;
    g_Mesh11.m_pSubsetArray = new SDKMESH_SUBSET;
    g_Mesh11.m_pSubsetArray[g_Mesh11.m_pMeshArray[0].pSubsets[0]] = v_subset;

    return true;
}

移植DXUT SDKMesh导入OBJ文件，在哪里添加纹理坐标和索引？

Porting DXUT SDKMesh to import OBJ files, where to add texture coordinates and indices?

c++

winapi

direct3d

directx-11

visual-studio