我正在尝试将Open Asset Import Library(读取各种3D模型文件类型)的多功能性与NVidia Optix光线跟踪相结合来渲染模型。
到目前为止,只要我渲染的模型由单个网格组成,它就能正常工作。当我尝试渲染具有多个网格的文件时,我只得到部分结果。我无法缩小问题所在,寻找一些见解。相关代码:
使用assimp导入器加载文件并创建optix缓冲区:
int loadAsset(const char* path)
{
Assimp::Importer importer;
scene = importer.ReadFile(
path,
aiProcess_Triangulate
//| aiProcess_JoinIdenticalVertices
| aiProcess_SortByPType
| aiProcess_ValidateDataStructure
| aiProcess_SplitLargeMeshes
| aiProcess_FixInfacingNormals
);
if (scene) {
getBoundingBox(&scene_min, &scene_max);
scene_center.x = (scene_min.x + scene_max.x) / 2.0f;
scene_center.y = (scene_min.y + scene_max.y) / 2.0f;
scene_center.z = (scene_min.z + scene_max.z) / 2.0f;
float3 optixMin = { scene_min.x, scene_min.y, scene_min.z };
float3 optixMax = { scene_max.x, scene_max.y, scene_max.z };
aabb.set(optixMin, optixMax);
unsigned int numVerts = 0;
unsigned int numFaces = 0;
if (scene->mNumMeshes > 0) {
printf("Number of meshes: %d\n", scene->mNumMeshes);
// get the running total number of vertices & faces for all meshes
for (unsigned int i = 0; i < scene->mNumMeshes; i++) {
numVerts += scene->mMeshes[i]->mNumVertices;
numFaces += scene->mMeshes[i]->mNumFaces;
}
printf("Found %d Vertices and %d Faces\n", numVerts, numFaces);
// set up buffers
optix::Buffer vertices = context->createBuffer(RT_BUFFER_INPUT, RT_FORMAT_FLOAT3, numVerts);
optix::Buffer normals = context->createBuffer(RT_BUFFER_INPUT, RT_FORMAT_FLOAT3, numVerts);
optix::Buffer faces = context->createBuffer(RT_BUFFER_INPUT, RT_FORMAT_UNSIGNED_INT3, numFaces);
optix::Buffer materials = context->createBuffer(RT_BUFFER_INPUT, RT_FORMAT_UNSIGNED_INT, numVerts);
// unused buffer
Buffer tbuffer = context->createBuffer(RT_BUFFER_INPUT, RT_FORMAT_FLOAT2, 0);
// create material
std::string defaultPtxPath = "C:\\ProgramData\\NVIDIA Corporation\\OptiX SDK 4.1.0\\SDK\\build\\lib\\ptx\\";
Program phong_ch = context->createProgramFromPTXFile(defaultPtxPath + "optixPrimitiveIndexOffsets_generated_phong.cu.ptx", "closest_hit_radiance");
Program phong_ah = context->createProgramFromPTXFile(defaultPtxPath + "optixPrimitiveIndexOffsets_generated_phong.cu.ptx", "any_hit_shadow");
Material matl = context->createMaterial();
matl->setClosestHitProgram(0, phong_ch);
matl->setAnyHitProgram(1, phong_ah);
matl["Kd"]->setFloat(0.7f, 0.7f, 0.7f);
matl["Ka"]->setFloat(1.0f, 1.0f, 1.0f);
matl["Kr"]->setFloat(0.0f, 0.0f, 0.0f);
matl["phong_exp"]->setFloat(1.0f);
std::string triangle_mesh_ptx_path(ptxPath("triangle_mesh.cu"));
Program meshIntersectProgram = context->createProgramFromPTXFile(triangle_mesh_ptx_path, "mesh_intersect");
Program meshBboxProgram = context->createProgramFromPTXFile(triangle_mesh_ptx_path, "mesh_bounds");
optix::float3 *vertexMap = reinterpret_cast<optix::float3*>(vertices->map());
optix::float3 *normalMap = reinterpret_cast<optix::float3*>(normals->map());
optix::uint3 *faceMap = reinterpret_cast<optix::uint3*>(faces->map());
unsigned int *materialsMap = static_cast<unsigned int*>(materials->map());
context["vertex_buffer"]->setBuffer(vertices);
context["normal_buffer"]->setBuffer(normals);
context["index_buffer"]->setBuffer(faces);
context["texcoord_buffer"]->setBuffer(tbuffer);
context["material_buffer"]->setBuffer(materials);
Group group = createSingleGeometryGroup(meshIntersectProgram, meshBboxProgram, vertexMap,
normalMap, faceMap, materialsMap, matl);
context["top_object"]->set(group);
context["top_shadower"]->set(group);
vertices->unmap();
normals->unmap();
faces->unmap();
materials->unmap();
}
return 0;
}
return 1;
}
用于创建几何和填充缓冲区的相关函数:
Group createSingleGeometryGroup(Program meshIntersectProgram, Program meshBboxProgram, optix::float3 *vertexMap,
optix::float3 *normalMap, optix::uint3 *faceMap, unsigned int *materialsMap, Material matl) {
Group group = context->createGroup();
optix::Acceleration accel = context->createAcceleration("Trbvh");
group->setAcceleration(accel);
std::vector<GeometryInstance> gis;
unsigned int vertexOffset = 0u;
unsigned int faceOffset = 0u;
for (unsigned int m = 0; m < scene->mNumMeshes; m++) {
aiMesh *mesh = scene->mMeshes[m];
if (!mesh->HasPositions()) {
throw std::runtime_error("Mesh contains zero vertex positions");
}
if (!mesh->HasNormals()) {
throw std::runtime_error("Mesh contains zero vertex normals");
}
printf("Mesh #%d\n\tNumVertices: %d\n\tNumFaces: %d\n", m, mesh->mNumVertices, mesh->mNumFaces);
// add points
for (unsigned int i = 0u; i < mesh->mNumVertices; i++) {
aiVector3D pos = mesh->mVertices[i];
aiVector3D norm = mesh->mNormals[i];
vertexMap[i + vertexOffset] = optix::make_float3(pos.x, pos.y, pos.z) + aabb.center();
normalMap[i + vertexOffset] = optix::normalize(optix::make_float3(norm.x, norm.y, norm.z));
materialsMap[i + vertexOffset] = 0u;
}
// add faces
for (unsigned int i = 0u; i < mesh->mNumFaces; i++) {
aiFace face = mesh->mFaces[i];
// add triangles
if (face.mNumIndices == 3) {
faceMap[i + faceOffset] = optix::make_uint3(face.mIndices[0], face.mIndices[1], face.mIndices[2]);
}
else {
printf("face indices != 3\n");
faceMap[i + faceOffset] = optix::make_uint3(-1);
}
}
// create geometry
optix::Geometry geometry = context->createGeometry();
geometry->setPrimitiveCount(mesh->mNumFaces);
geometry->setIntersectionProgram(meshIntersectProgram);
geometry->setBoundingBoxProgram(meshBboxProgram);
geometry->setPrimitiveIndexOffset(faceOffset);
optix::GeometryInstance gi = context->createGeometryInstance(geometry, &matl, &matl + 1);
gis.push_back(gi);
vertexOffset += mesh->mNumVertices;
faceOffset += mesh->mNumFaces;
}
printf("VertexOffset: %d\nFaceOffset: %d\n", vertexOffset, faceOffset);
// add all geometry instances to a geometry group
GeometryGroup gg = context->createGeometryGroup();
gg->setChildCount(static_cast<unsigned int>(gis.size()));
for (unsigned i = 0u; i < gis.size(); i++) {
gg->setChild(i, gis[i]);
}
Acceleration a = context->createAcceleration("Trbvh");
gg->setAcceleration(a);
group->setChildCount(1);
group->setChild(0, gg);
return group;
}
在assimp的示例文件上运行上面的代码(使用dwarf.x,文件包含2个网格)会产生以下结果:
你只能看到第二个网格的一部分(矮人的身体)被渲染。我尝试分别渲染每个网格,一次一个,然后渲染完整。但是当把它们放在一起时,我得到了它。
我认为问题在于创建几何体,或许我有这些线错:
geometry->setPrimitiveCount(mesh->mNumFaces);
geometry->setPrimitiveIndexOffset(faceOffset);
或assimp后处理标志
scene = importer.ReadFile(
path,
aiProcess_Triangulate
//| aiProcess_JoinIdenticalVertices
| aiProcess_SortByPType
| aiProcess_ValidateDataStructure
| aiProcess_SplitLargeMeshes
| aiProcess_FixInfacingNormals
);
(注意上面,我必须注释掉JoinIdenticalVertices,因为它给了我一个可怕的错误结果,如下所示):
有没有人能够成功地将nvidia optix与开放资产导入库相结合,以渲染具有多个网格的文件?
答案 0 :(得分:2)
我找到了一个解决方案,虽然不确定它是多么优化。
每个网格仍然获得自己的几何体,但是不是创建在所有几何体之间共享的单个顶点,索引和常规缓冲区,而是为每个几何体创建单独的缓冲区。
然后,而不是
context["vertex_buffer"]->setBuffer(vertices);
context["normal_buffer"]->setBuffer(normals);
context["index_buffer"]->setBuffer(faces);
context["texcoord_buffer"]->setBuffer(tbuffer);
context["material_buffer"]->setBuffer(materials);
我用
geometry["vertex_buffer"]->setBuffer(vertices);
geometry["normal_buffer"]->setBuffer(normals);
geometry["index_buffer"]->setBuffer(faces);
geometry["texcoord_buffer"]->setBuffer(tbuffer);
geometry["material_buffer"]->setBuffer(materials);