Add dedicated tests for support point generation

tests/sla_print/sla_supptgen_tests.cpp

@@ -0,0 +1,148 @@
+#include <catch2/catch.hpp>
+#include <test_utils.hpp>
+
+#include <libslic3r/ExPolygon.hpp>
+#include <libslic3r/BoundingBox.hpp>
+
+#include "sla_test_utils.hpp"
+
+namespace Slic3r { namespace sla {
+
+TEST_CASE("Overhanging point should be supported", "[SupGen]") {
+
+    // Pyramid with 45 deg slope
+    TriangleMesh mesh = make_pyramid(10.f, 10.f);
+    mesh.rotate_y(PI);
+    mesh.require_shared_vertices();
+    mesh.WriteOBJFile("Pyramid.obj");
+
+    sla::SupportPoints pts = calc_support_pts(mesh);
+
+    // The overhang, which is the upside-down pyramid's edge
+    Vec3f overh{0., 0., -10.};
+
+    REQUIRE(!pts.empty());
+
+    float dist = (overh - pts.front().pos).norm();
+
+    for (const auto &pt : pts)
+        dist = std::min(dist, (overh - pt.pos).norm());
+
+    // Should require exactly one support point at the overhang
+    REQUIRE(pts.size() > 0);
+    REQUIRE(dist < 1.f);
+}
+
+double min_point_distance(const sla::SupportPoints &pts)
+{
+    sla::PointIndex index;
+
+    for (size_t i = 0; i < pts.size(); ++i)
+        index.insert(pts[i].pos.cast<double>(), i);
+
+    auto d = std::numeric_limits<double>::max();
+    index.foreach([&d, &index](const sla::PointIndexEl &el) {
+        auto res = index.nearest(el.first, 2);
+        for (const sla::PointIndexEl &r : res)
+            if (r.second != el.second)
+                d = std::min(d, (el.first - r.first).norm());
+    });
+
+    return d;
+}
+
+TEST_CASE("Overhanging horizontal surface should be supported", "[SupGen]") {
+    double width = 10., depth = 10., height = 1.;
+
+    TriangleMesh mesh = make_cube(width, depth, height);
+    mesh.translate(0., 0., 5.); // lift up
+    mesh.require_shared_vertices();
+    mesh.WriteOBJFile("Cuboid.obj");
+
+    sla::SupportPointGenerator::Config cfg;
+    sla::SupportPoints pts = calc_support_pts(mesh, cfg);
+
+    double mm2 = width * depth;
+
+    REQUIRE(!pts.empty());
+    REQUIRE(pts.size() * cfg.support_force() > mm2 * cfg.tear_pressure());
+    REQUIRE(min_point_distance(pts) >= cfg.minimal_distance);
+}
+
+template<class M> auto&& center_around_bb(M &&mesh)
+{
+    auto bb = mesh.bounding_box();
+    mesh.translate(-bb.center().template cast<float>());
+
+    return std::forward<M>(mesh);
+}
+
+TEST_CASE("Overhanging edge should be supported", "[SupGen]") {
+    float width = 10.f, depth = 10.f, height = 5.f;
+
+    TriangleMesh mesh = make_prism(width, depth, height);
+    mesh.rotate_y(PI); // rotate on its back
+    mesh.translate(0., 0., height);
+    mesh.require_shared_vertices();
+    mesh.WriteOBJFile("Prism.obj");
+
+    sla::SupportPointGenerator::Config cfg;
+    sla::SupportPoints pts = calc_support_pts(mesh, cfg);
+
+    REQUIRE(min_point_distance(pts) >= cfg.minimal_distance);
+
+    Linef3 overh{ {0.f, -depth / 2.f, 0.f}, {0.f, depth / 2.f, 0.f}};
+
+    // Get all the points closer that 1 mm to the overhanging edge:
+    sla::SupportPoints overh_pts; overh_pts.reserve(pts.size());
+
+    std::copy_if(pts.begin(), pts.end(), std::back_inserter(overh_pts),
+                 [&overh](const sla::SupportPoint &pt){
+                     return line_alg::distance_to(overh, Vec3d{pt.pos.cast<double>()}) < 1.;
+                 });
+
+    REQUIRE(overh_pts.size() * cfg.support_force() > overh.length() * cfg.tear_pressure());
+    REQUIRE(min_point_distance(pts) >= cfg.minimal_distance);
+}
+
+// FIXME: Not working yet
+//TEST_CASE("Hollowed cube should be supported from the inside", "[SupGen][Hollowed]") {
+//    TriangleMesh mesh = make_cube(20., 20., 20.);
+
+//    hollow_mesh(mesh, HollowingConfig{});
+
+//    mesh.WriteOBJFile("cube_hollowed.obj");
+
+//    auto bb = mesh.bounding_box();
+//    auto h  = float(bb.max.z() - bb.min.z());
+//    Vec3f mv = bb.center().cast<float>() - Vec3f{0.f, 0.f, 0.5f * h};
+//    mesh.translate(-mv);
+//    mesh.require_shared_vertices();
+
+//    sla::SupportPointGenerator::Config cfg;
+//    sla::SupportPoints pts = calc_support_pts(mesh, cfg);
+//    sla::remove_bottom_points(pts, mesh.bounding_box().min.z() + EPSILON);
+
+//    REQUIRE(!pts.empty());
+//}
+
+TEST_CASE("Two parallel plates should be supported", "[SupGen][Hollowed]")
+{
+    double width = 20., depth = 20., height = 1.;
+
+    TriangleMesh mesh = center_around_bb(make_cube(width + 5., depth + 5., height));
+    TriangleMesh mesh_high = center_around_bb(make_cube(width, depth, height));
+    mesh_high.translate(0., 0., 10.); // lift up
+    mesh.merge(mesh_high);
+    mesh.require_shared_vertices();
+
+    mesh.WriteOBJFile("parallel_plates.obj");
+
+    sla::SupportPointGenerator::Config cfg;
+    sla::SupportPoints pts = calc_support_pts(mesh, cfg);
+    sla::remove_bottom_points(pts, mesh.bounding_box().min.z() + EPSILON);
+
+    REQUIRE(!pts.empty());
+}
+
+}} // namespace Slic3r::sla