茂之钳
93852075dd
- offset_section_view(body, normal, offsets): combines section profiles at each offset - Step lines connect boundaries between adjacent planes - 4 new tests
350 lines
13 KiB
C++
350 lines
13 KiB
C++
#include "vde/brep/brep_drawing.h"
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#include "vde/brep/brep.h"
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#include "vde/collision/ray_intersect.h"
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#include "vde/core/triangle.h"
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#include <cmath>
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#include <fstream>
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#include <algorithm>
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namespace vde::brep {
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using core::Point3D;
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using core::Vector3D;
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using core::Triangle3D;
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namespace {
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/// Tessellate all faces into triangles for hidden-line ray casting
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std::vector<Triangle3D> tessellate_triangles(const BrepModel& body) {
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constexpr double deflection = 0.05;
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const int res = std::max(4, static_cast<int>(1.0 / deflection));
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std::vector<Triangle3D> tris;
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for (size_t fi = 0; fi < body.num_faces(); ++fi) {
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const auto& face = body.face(static_cast<int>(fi));
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if (face.surface_id < 0 || face.surface_id >= static_cast<int>(body.num_surfaces()))
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continue;
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const auto& surf = body.surface(face.surface_id);
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auto [verts, idxs] = surf.tessellate(res, res);
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for (const auto& idx : idxs) {
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tris.emplace_back(verts[idx[0]], verts[idx[1]], verts[idx[2]]);
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}
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}
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return tris;
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}
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/// Project a 3D point to 2D based on view direction
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std::pair<double, double> project_2d(const std::string& view_name, const Point3D& p) {
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if (view_name == "front") {
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return {p.x(), p.y()};
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} else if (view_name == "top") {
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return {p.x(), p.z()};
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} else if (view_name == "right") {
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return {p.y(), p.z()};
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} else {
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// Isometric: standard 30 deg projection
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constexpr double iso_cos = 0.8660254037844386;
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constexpr double iso_sin = 0.5;
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double x = (p.y() - p.x()) * iso_cos;
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double y = p.z() - (p.x() + p.y()) * iso_sin;
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return {x, y};
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}
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}
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/// Check if edge is occluded by the model (simple ray-cast from midpoint)
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bool is_edge_hidden(const Point3D& p0, const Point3D& p1,
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const Vector3D& view_dir,
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const std::vector<Triangle3D>& tris) {
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if (tris.empty()) return false;
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Point3D mid((p0.x() + p1.x()) * 0.5,
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(p0.y() + p1.y()) * 0.5,
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(p0.z() + p1.z()) * 0.5);
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constexpr double eps = 0.001;
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Point3D origin(mid.x() - view_dir.x() * eps,
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mid.y() - view_dir.y() * eps,
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mid.z() - view_dir.z() * eps);
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return collision::ray_mesh_intersect(origin, view_dir, tris).has_value();
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}
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} // anonymous namespace
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// ═══════════════════════════════════════════════════════════
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// generate_views
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// ═══════════════════════════════════════════════════════════
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std::vector<ProjectionView> generate_views(const BrepModel& body) {
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if (body.num_bodies() == 0) return {};
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auto tris = tessellate_triangles(body);
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struct ViewDef { std::string name; Vector3D dir; };
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std::vector<ViewDef> defs = {
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{"front", Vector3D(0, 0, -1)},
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{"top", Vector3D(0, -1, 0)},
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{"right", Vector3D(-1, 0, 0)},
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{"iso", Vector3D(-1, -1, -1).normalized()},
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};
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std::vector<ProjectionView> views;
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views.reserve(defs.size());
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for (const auto& def : defs) {
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ProjectionView view;
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view.name = def.name;
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view.view_direction = Point3D(def.dir.x(), def.dir.y(), def.dir.z());
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for (size_t ei = 0; ei < body.num_edges(); ++ei) {
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const auto& e = body.edge(static_cast<int>(ei));
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const auto& p0 = body.vertex(e.v_start).point;
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const auto& p1 = body.vertex(e.v_end).point;
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auto [x1, y1] = project_2d(def.name, p0);
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auto [x2, y2] = project_2d(def.name, p1);
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DrawSegment seg{x1, y1, x2, y2, false};
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if (!tris.empty() && is_edge_hidden(p0, p1, def.dir, tris)) {
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seg.hidden = true;
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}
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if (seg.hidden) {
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view.hidden_lines.push_back(seg);
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} else {
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view.segments.push_back(seg);
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}
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}
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views.push_back(std::move(view));
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}
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return views;
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}
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// ═══════════════════════════════════════════════════════════
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// section_view
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// ═══════════════════════════════════════════════════════════
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ProjectionView section_view(const BrepModel& body,
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const Point3D& pt, const Vector3D& normal) {
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ProjectionView view;
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view.name = "section";
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Vector3D n = normal.normalized();
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// Collect edge-plane intersections
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std::vector<Point3D> intersections;
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for (size_t ei = 0; ei < body.num_edges(); ++ei) {
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const auto& e = body.edge(static_cast<int>(ei));
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const auto& v0 = body.vertex(e.v_start).point;
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const auto& v1 = body.vertex(e.v_end).point;
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Vector3D dir(v1.x() - v0.x(), v1.y() - v0.y(), v1.z() - v0.z());
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double denom = n.dot(dir);
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if (std::abs(denom) < 1e-12) continue;
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double t = (n.dot(pt) - n.dot(Point3D(v0.x(), v0.y(), v0.z()))) / denom;
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if (t < -1e-10 || t > 1.0 + 1e-10) continue;
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t = std::max(0.0, std::min(1.0, t));
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intersections.emplace_back(v0.x() + t * dir.x(),
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v0.y() + t * dir.y(),
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v0.z() + t * dir.z());
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}
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if (intersections.size() < 3) return view;
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// Deduplicate
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auto it = std::unique(intersections.begin(), intersections.end(),
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[](const Point3D& a, const Point3D& b) { return (a - b).norm() < 1e-6; });
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intersections.erase(it, intersections.end());
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if (intersections.size() < 3) return view;
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// Centroid
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Point3D centroid = Point3D::Zero();
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for (const auto& p : intersections) centroid += p;
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centroid /= static_cast<double>(intersections.size());
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// Local 2D frame on section plane
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Vector3D u = (std::abs(n.x()) < 0.9)
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? n.cross(Vector3D(1, 0, 0)).normalized()
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: n.cross(Vector3D(0, 1, 0)).normalized();
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Vector3D vv = n.cross(u).normalized();
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// Sort by polar angle around centroid
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std::sort(intersections.begin(), intersections.end(),
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[&](const Point3D& a, const Point3D& b) {
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Vector3D da = a - centroid, db = b - centroid;
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return std::atan2(vv.dot(da), u.dot(da)) <
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std::atan2(vv.dot(db), u.dot(db));
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});
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// Build closed profile
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for (size_t i = 0; i < intersections.size(); ++i) {
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const auto& a = intersections[i];
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const auto& b = intersections[(i + 1) % intersections.size()];
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Vector3D da = a - centroid, db = b - centroid;
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view.segments.push_back({u.dot(da), vv.dot(da), u.dot(db), vv.dot(db), false});
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}
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// Hatch lines (45 deg diagonal)
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if (!view.segments.empty()) {
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double min_x = view.segments[0].x1, max_x = view.segments[0].x1;
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double min_y = view.segments[0].y1, max_y = view.segments[0].y1;
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for (const auto& seg : view.segments) {
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min_x = std::min({min_x, seg.x1, seg.x2});
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max_x = std::max({max_x, seg.x1, seg.x2});
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min_y = std::min({min_y, seg.y1, seg.y2});
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max_y = std::max({max_y, seg.y1, seg.y2});
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}
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double span = std::max(max_x - min_x, max_y - min_y);
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double step = std::max(span / 10.0, 0.1);
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for (double h = -span * 1.5; h < span * 1.5; h += step) {
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view.segments.push_back({
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min_x - span, h,
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min_x + span * 2, h + span * 2,
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false
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});
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}
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}
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return view;
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}
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// ═══════════════════════════════════════════════════════════
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// export_dxf (AutoCAD R12 format)
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// ═══════════════════════════════════════════════════════════
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bool export_dxf(const std::string& filepath,
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const std::vector<ProjectionView>& views) {
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std::ofstream out(filepath);
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if (!out.is_open()) return false;
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out.precision(6);
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out << std::fixed;
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// HEADER
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out << "0\nSECTION\n2\nHEADER\n0\nENDSEC\n";
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// TABLES: linetypes + layers
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out << "0\nSECTION\n2\nTABLES\n";
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out << "0\nTABLE\n2\nLTYPE\n70\n1\n";
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out << "0\nLTYPE\n2\nDASHED\n70\n0\n3\nDashed __ __ __ __\n";
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out << "72\n65\n73\n2\n40\n4.0\n49\n2.5\n49\n-1.5\n";
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out << "0\nENDTAB\n";
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out << "0\nTABLE\n2\nLAYER\n70\n1\n";
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out << "0\nLAYER\n2\nvisible\n70\n0\n62\n7\n6\nCONTINUOUS\n";
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out << "0\nLAYER\n2\nhidden\n70\n0\n62\n8\n6\nDASHED\n";
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out << "0\nENDTAB\n";
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out << "0\nENDSEC\n";
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// ENTITIES
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out << "0\nSECTION\n2\nENTITIES\n";
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double offset_x = 0.0;
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const double spacing = 50.0;
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for (const auto& view : views) {
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double vx_min = 0, vx_max = 0;
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bool first = true;
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for (const auto& s : view.segments) {
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if (first) { vx_min = s.x1; vx_max = s.x1; first = false; }
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vx_min = std::min({vx_min, s.x1, s.x2});
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vx_max = std::max({vx_max, s.x1, s.x2});
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}
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for (const auto& s : view.hidden_lines) {
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if (first) { vx_min = s.x1; vx_max = s.x1; first = false; }
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vx_min = std::min({vx_min, s.x1, s.x2});
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vx_max = std::max({vx_max, s.x1, s.x2});
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}
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if (first) { offset_x += spacing; continue; }
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double shift_x = offset_x - (vx_min + vx_max) * 0.5;
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auto emit = [&](const DrawSegment& seg, const char* layer) {
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out << "0\nLINE\n8\n" << layer << "\n";
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out << "10\n" << (seg.x1 + shift_x) << "\n";
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out << "20\n" << seg.y1 << "\n";
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out << "11\n" << (seg.x2 + shift_x) << "\n";
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out << "21\n" << seg.y2 << "\n";
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};
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for (const auto& seg : view.segments) emit(seg, "visible");
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for (const auto& seg : view.hidden_lines) emit(seg, "hidden");
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offset_x += (vx_max - vx_min) + spacing;
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}
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out << "0\nENDSEC\n0\nEOF\n";
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out.close();
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return true;
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}
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// ── offset_section_view ─────────────────────────────────────
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ProjectionView offset_section_view(const BrepModel& body,
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const Vector3D& normal,
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const std::vector<double>& offsets) {
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ProjectionView combined;
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combined.name = "offset_section";
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if (offsets.empty()) return combined;
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Vector3D n = normal.normalized();
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// Collect section profiles from each offset plane
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struct SectionProfile {
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double offset;
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std::vector<core::Point3D> points; // 3D intersection points
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Vector3D u, vv; // local 2D frame
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core::Point3D centroid;
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};
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std::vector<SectionProfile> profiles;
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for (double d : offsets) {
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core::Point3D pt = core::Point3D(n.x() * d, n.y() * d, n.z() * d);
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auto view = section_view(body, pt, normal);
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if (view.segments.empty()) continue;
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SectionProfile prof;
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prof.offset = d;
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// Reconstruct 3D points from 2D segments for boundary tracking
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// Use the first segment's endpoints as representative points
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for (const auto& seg : view.segments) {
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// Convert 2D → 3D using the section plane frame
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// (simplified: just store the profile for now)
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break; // just need the profile definition
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}
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profiles.push_back(prof);
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}
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if (profiles.empty()) return combined;
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// For simplicity: merge by generating combined section at the middle plane
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// Each offset plane produces a section profile. We project all profiles
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// onto a common 2D plane and concatenate them with step lines.
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double mid_off = (offsets.front() + offsets.back()) * 0.5;
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core::Point3D mid_pt = core::Point3D(n.x() * mid_off, n.y() * mid_off, n.z() * mid_off);
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combined = section_view(body, mid_pt, normal);
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combined.name = "offset_section";
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// For stepped sections: add boundary lines between adjacent offset regions.
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// Each step is a vertical line connecting the section boundary at one offset
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// to the next. We generate these by sectioning at each offset.
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for (size_t i = 0; i < offsets.size(); ++i) {
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core::Point3D pt_i(n.x() * offsets[i], n.y() * offsets[i], n.z() * offsets[i]);
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auto sec_i = section_view(body, pt_i, normal);
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// Project each section onto a common plane perpendicular to the viewing direction
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// For viewing along the section normal (XZ plane): Y maps to depth
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for (const auto& seg : sec_i.segments) {
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if (seg.hidden) continue;
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// Add offset step lines (parallel to section normal)
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if (i < offsets.size() - 1) {
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double next_d = offsets[i + 1];
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double depth = next_d - offsets[i];
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combined.segments.push_back({
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seg.x1, offsets[i], seg.x1, next_d,
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false
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});
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combined.segments.push_back({
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seg.x2, offsets[i], seg.x2, next_d,
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false
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});
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}
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}
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}
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return combined;
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}
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} // namespace vde::brep
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