cSkinMesh类的设计与实现 cSkinMesh类的实现与cAnimMesh的实现基本相同，区别在以下几点。
首先是在load_from_xfile()中增加了对网格模型骨骼矩阵的保存：
HRESULT cSkinMesh::setup_bone_matrix_pointers(D3DXFRAME* frame)
{
HRESULT hr;
if(frame == NULL)
return S_OK;
if(frame->pMeshContainer != NULL)
{
hr = setup_bone_matrix_pointers_on_mesh(frame->pMeshContainer);
if(FAILED(hr))
return hr;
}
if(frame->pFrameSibling != NULL)
{
hr = setup_bone_matrix_pointers(frame->pFrameSibling);
if(FAILED(hr))
return hr;
}
if(frame->pFrameFirstChild != NULL)
{
hr = setup_bone_matrix_pointers(frame->pFrameFirstChild);
if(FAILED(hr))
return hr;
}
return S_OK;
}
HRESULT cSkinMesh::setup_bone_matrix_pointers_on_mesh(D3DXMESHCONTAINER* base_mesh_container)
{
if(base_mesh_container == NULL)
return S_OK;
D3DXMESHCONTAINER_DERIVED* mesh_container = (D3DXMESHCONTAINER_DERIVED*) base_mesh_container;
if(mesh_container->pSkinInfo != NULL)
{
UINT num_bones = mesh_container->pSkinInfo->GetNumBones();
mesh_container->ppBoneMatrices = new D3DXMATRIX*[num_bones];
if(mesh_container->ppBoneMatrices == NULL)
return E_OUTOFMEMORY;
for(UINT i = 0; i < num_bones; i++)
{
LPCSTR bone_name = mesh_container->pSkinInfo->GetBoneName(i);
D3DXFRAME_DERIVED* frame = (D3DXFRAME_DERIVED*) D3DXFrameFind(m_root_frame, bone_name);
if(frame == NULL)
return E_FAIL;
mesh_container->ppBoneMatrices[i] = &frame->CombinedTransformMatrix;
}
}
return S_OK;
}
HRESULT cSkinMesh::load_from_xfile(CONST WCHAR* wfilename)
{
HRESULT hr;
WCHAR wpath[MAX_PATH];
DXUTFindDXSDKMediaFileCch(wpath, sizeof(wpath) / sizeof(WCHAR), wfilename);
V_RETURN(D3DXLoadMeshHierarchyFromXW(wpath, D3DXMESH_MANAGED, m_device, m_alloc_hierarchy, NULL, &m_root_frame,
&m_anim_controller));
V_RETURN(setup_bone_matrix_pointers(m_root_frame));
V_RETURN(D3DXFrameCalculateBoundingSphere(m_root_frame, &m_object_center, &m_object_radius));
return S_OK;
}
接下来是DrawMeshContainer()的实现，该函数负责当前网格容器中具体网格模型的渲染，其实现大致可以分为以下几个步骤：
【1】如果当前网格模型是蒙皮网格模型
（1）根据当前硬件设备的性能决定是否采用软件顶点处理模式。
（2）激活索引顶点混合。
（3）设置顶点混合所需要的矩阵索引数量。
（4）渲染索引蒙皮网格模型，在具体渲染时，需要逐个属性组进行渲染，在渲染每个子网格时，首先需要设置骨骼混合矩阵、材质和数组。
（5）恢复相关渲染状态。
【2】如果当前网格模型不是蒙皮网格模型，则直接设置组合变换矩阵、材质和纹理，然后进行渲染。
HRESULT cSkinMesh::draw_mesh_container(CONST D3DXMESHCONTAINER* base_mesh_container, CONST D3DXFRAME* base_frame)
{
HRESULT hr;
D3DXMESHCONTAINER_DERIVED* mesh_container = (D3DXMESHCONTAINER_DERIVED*) base_mesh_container;
D3DXFRAME_DERIVED* frame = (D3DXFRAME_DERIVED*) base_frame;
if(mesh_container->pSkinInfo != NULL)
{
if(mesh_container->UseSoftwareVP)
{
V_RETURN(m_device->SetSoftwareVertexProcessing(TRUE));
}
if(mesh_container->MaxBonesInflPerVertex)
m_device->SetRenderState(D3DRS_INDEXEDVERTEXBLENDENABLE, TRUE);
if(mesh_container->MaxBonesInflPerVertex == 1)
m_device->SetRenderState(D3DRS_VERTEXBLEND, D3DVBF_0WEIGHTS);
else if(mesh_container->MaxBonesInflPerVertex == 2)
m_device->SetRenderState(D3DRS_VERTEXBLEND, D3DVBF_1WEIGHTS);
else if(mesh_container->MaxBonesInflPerVertex == 3)
m_device->SetRenderState(D3DRS_VERTEXBLEND, D3DVBF_2WEIGHTS);
else
m_device->SetRenderState(D3DRS_VERTEXBLEND, D3DVBF_3WEIGHTS);
D3DXBONECOMBINATION* bone_comb = (D3DXBONECOMBINATION*) mesh_container->pBoneCombBuffer->GetBufferPointer();
for(UINT attr_index = 0; attr_index < mesh_container->NumAttrGroups; attr_index++)
{
// setup vertex index blending world matrix for every mesh group
for(UINT palette_index = 0; palette_index < mesh_container->NumMatrixPalettes; palette_index++)
{
UINT matrix_index = bone_comb[attr_index].BoneId[palette_index];
if(matrix_index != UINT_MAX)
{
D3DXMATRIX mat_palette;
D3DXMatrixMultiply(&mat_palette,
mesh_container->ppBoneOffsetMatrices[matrix_index],
mesh_container->ppBoneMatrices[matrix_index]);
m_device->SetTransform(D3DTS_WORLDMATRIX(palette_index), &mat_palette);
}
}
DWORD attr_id = bone_comb[attr_index].AttribId;
m_device->SetMaterial(&mesh_container->pMaterials[attr_id].MatD3D);
m_device->SetTexture(0, mesh_container->ppTextures[attr_id]);
mesh_container->MeshData.pMesh->DrawSubset(attr_index);
}
// restore render state
m_device->SetRenderState(D3DRS_INDEXEDVERTEXBLENDENABLE, FALSE);
m_device->SetRenderState(D3DRS_VERTEXBLEND, D3DVBF_DISABLE);
if(mesh_container->UseSoftwareVP)
{
V_RETURN(m_device->SetSoftwareVertexProcessing(FALSE));
}
}
else
{
m_device->SetTransform(D3DTS_WORLD, &frame->CombinedTransformMatrix);
for(UINT i = 0; i < mesh_container->NumMaterials; i++)
{
m_device->SetMaterial(&mesh_container->pMaterials[i].MatD3D);
m_device->SetTexture(0, mesh_container->ppTextures[i]);
mesh_container->MeshData.pMesh->DrawSubset(i);
}
}
return S_OK;
}
蒙皮骨骼动画网格模型类的使用
首先需要修改顶点处理模式，如果当前Direct3D设备使用纯硬件顶点处理模式，则改为混合顶点处理模式：
// If video card does not support hardware transform and light, then uses sofaware mode.if((pCaps->DevCaps & D3DDEVCAPS_HWTRANSFORMANDLIGHT) == 0) pDeviceSettings->BehaviorFlags = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
// !!important, change vertex processing to mixed mode.if(pDeviceSettings->BehaviorFlags & D3DCREATE_HARDWARE_VERTEXPROCESSING) pDeviceSettings->BehaviorFlags = D3DCREATE_MIXED_VERTEXPROCESSING;
因为硬件可能不支持索引顶点混合，这时就需要使用软件顶点处理，所以在使用cSkinMesh类渲染蒙皮骨骼动画网格模型的程序中，如果Direct3D设备使用纯硬件顶点处理模式，则需要改为混合顶点处理模式，否则在调用IDirect3DDevice9::SetSoftwareProcessing()函数将顶点处理模式改为软件顶点处理模式时会出错。
接下来在回调函数OnCreateDevice()中创建cSkinMesh类的实例：
g_skin_mesh = new cSkinMesh();
V_RETURN(g_skin_mesh->create(pd3dDevice, L"tiny.x"));
再接下来在回调函数OnFrameRender()中渲染网格模型：
V(g_skin_mesh->render(&g_mat_world, fElapsedTime));
最后在回调函数OnDestroyDevice()中释放网格模型：
g_skin_mesh->destroy();
运行截图：
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计算机技术与应用 → 『 C/C++编程思想 』 → 网格模型高级技术（4）
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2009/1/5 13:44:00
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网格模型高级技术（4）(7681字) － 卷积内核，2009年1月5日
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