138 lines
4.3 KiB
C++
138 lines
4.3 KiB
C++
#include <future>
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#include <nori/octree.h>
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#include <tbb/tbb.h>
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NORI_NAMESPACE_BEGIN
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Octree *Octree::build(BoundingBox3f *bbox, Mesh *mesh, std::vector<uint32_t> &triangles, int recursionDepth) {
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auto node = new Octree(bbox, mesh);
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if (triangles.size() <= 20 || recursionDepth > 6) {
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node->setTriangles(triangles);
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return node;
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}
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auto m_F = mesh->getIndices();
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auto m_V = mesh->getVertexPositions();
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auto bMin = bbox->min;
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auto w = bbox->max.x() - bMin.x();
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auto h = bbox->max.y() - bMin.y();
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auto d = bbox->max.z() - bMin.z();
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auto w2 = w / 2.0f, h2 = h / 2.0f, d2 = d / 2.0f;
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BoundingBox3f *newBboxes[8] = {
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new BoundingBox3f(bMin + Vector3f(0, 0, 0), bMin + Vector3f(w2, h2, d2)),
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new BoundingBox3f(bMin + Vector3f(w2, 0, 0), bMin + Vector3f(w, h2, d2)),
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new BoundingBox3f(bMin + Vector3f(0, h2, 0), bMin + Vector3f(w2, h, d2)),
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new BoundingBox3f(bMin + Vector3f(w2, h2, 0), bMin + Vector3f(w, h, d2)),
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new BoundingBox3f(bMin + Vector3f(0, 0, d2), bMin + Vector3f(w2, h2, d)),
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new BoundingBox3f(bMin + Vector3f(w2, 0, d2), bMin + Vector3f(w, h2, d)),
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new BoundingBox3f(bMin + Vector3f(0, h2, d2), bMin + Vector3f(w2, h, d)),
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new BoundingBox3f(bMin + Vector3f(w2, h2, d2), bMin + Vector3f(w, h, d))
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};
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std::vector<uint32_t> childTriangles[8];
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BoundingBox3f triangleBbox;
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for(int i = 0; i < 8; i++) {
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childTriangles[i].reserve(triangles.size() / 8);
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for (uint32_t idx : triangles) {
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auto a = m_V.col(m_F(0, idx));
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auto b = m_V.col(m_F(1, idx));
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auto c = m_V.col(m_F(2, idx));
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triangleBbox.min = a.cwiseMin(b).cwiseMin(c);
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triangleBbox.max = a.cwiseMax(b).cwiseMax(c);
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if (newBboxes[i]->overlaps(triangleBbox)) {
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childTriangles[i].push_back(idx);
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}
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}
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childTriangles[i].shrink_to_fit();
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}
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if (recursionDepth <= 2) {
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tbb::parallel_for(tbb::blocked_range<size_t>(0, 8), [&](const tbb::blocked_range<size_t> &range) {
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for (size_t i = range.begin(); i != range.end(); ++i) {
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if (childTriangles[i].empty()) {
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node->children[i] = nullptr;
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continue;
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}
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node->children[i] = build(newBboxes[i], mesh, childTriangles[i], recursionDepth + 1);
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}
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});
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} else {
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for (int i = 0; i < 8; i++) {
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if (childTriangles[i].empty()) {
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node->children[i] = nullptr;
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continue;
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}
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node->children[i] = build(newBboxes[i], mesh, childTriangles[i], recursionDepth + 1);
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}
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}
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return node;
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}
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uint32_t Octree::getIntersectingTriangle(Ray3f &ray, Intersection &its, bool shadowRay) {
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float u, v, t;
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uint32_t closestTriangle = -1;
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uint32_t triangle;
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Octree *tmpChildren[8];
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double distances[8];
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float nearT, farT;
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int n = 0;
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int i, j, k;
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if (triangles.empty()) {
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for (i = 0; i < 8; i++) {
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if (children[i] == nullptr) {
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continue;
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}
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if (!children[i]->bbox->rayIntersect(ray, nearT, farT)) {
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continue;
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}
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for (j = 0; j < n; j++) {
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if (farT >= distances[j]) {
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continue;
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}
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for (k = n; k > j; k--) {
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distances[k] = distances[k - 1];
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tmpChildren[k] = tmpChildren[k - 1];
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}
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break;
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}
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distances[j] = farT;
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tmpChildren[j] = children[i];
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n++;
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}
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for (i = 0; i < n; i++) {
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triangle = tmpChildren[i]->getIntersectingTriangle(ray, its, shadowRay);
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if (triangle != (uint32_t) -1) {
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return triangle;
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}
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}
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return -1;
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}
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for (auto triangle : triangles) {
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if (mesh->rayIntersect(triangle, ray, u, v, t)) {
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if (shadowRay) {
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return triangle;
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}
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if (t < ray.maxt) {
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ray.maxt = its.t = t;
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its.uv = Point2f(u, v);
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its.mesh = mesh;
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closestTriangle = triangle;
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}
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}
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}
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return closestTriangle;
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}
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NORI_NAMESPACE_END
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