3DPrinting/PrusaSlicer-NonPlainar
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Fixed a logic error in the algorithm

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The error created extremely large projections of triangles that were close to horizontal
This commit is contained in:
Lukas Matena 2020-04-22 09:24:52 +02:00
parent 7fc4a71715
commit 8d95345ede
1 changed files with 44 additions and 36 deletions
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80
src/libslic3r/PrintObject.cpp
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@ -2655,17 +2655,13 @@ void PrintObject::project_and_append_custom_supports(
const Transform3f& tr1 = mv->get_matrix().cast<float>();
const Transform3f& tr2 = this->trafo().cast<float>();
// List of all layers.
const LayerPtrs& layers = this->layers();
// Make sure that enforcers vector can be used.
// Make sure that the output vector can be used.
if (! custom_facets.empty())
expolys.resize(layers.size());
expolys.resize(layers().size());
// Iterate over all triangles.
for (int facet_idx : custom_facets) {
std::array<Vec3f, 3> facet;
std::array<float, 3> z_heights;
// Transform the triangle into worlds coords.
for (int i=0; i<3; ++i)
@ -2677,72 +2673,84 @@ void PrintObject::project_and_append_custom_supports(
return pt1.z() < pt2.z();
});
Polygon triangle;
std::array<Vec2f, 3> trianglef;
for (int i=0; i<3; ++i) {
z_heights[i] = facet[i].z();
triangle.append(Point::new_scale(facet[i].x(), facet[i].y()));
triangle.translate(this->center_offset());
trianglef[i] = Vec2f(facet[i].x(), facet[i].y());
trianglef[i] += Vec2f(unscale<float>(this->center_offset().x()),
unscale<float>(this->center_offset().y()));
}
// Find lowest slice not below the triangle.
auto it = std::lower_bound(layers.begin(), layers.end(), z_heights[0],
auto it = std::lower_bound(layers().begin(), layers().end(), facet[0].z()+EPSILON,
[](const Layer* l1, float z) {
return l1->slice_z < z;
});
// Calculate how to move points on triangle sides per unit z increment.
Point ta(triangle.points[1] - triangle.points[0]);
Point tb(triangle.points[2] - triangle.points[0]);
Vec2f ta(trianglef[1] - trianglef[0]);
Vec2f tb(trianglef[2] - trianglef[0]);
ta *= 1./(facet[1].z() - facet[0].z());
tb *= 1./(facet[2].z() - facet[0].z());
ta *= 1./(z_heights[1] - z_heights[0]);
tb *= 1./(z_heights[2] - z_heights[0]);
// Projection on current slice.
std::vector<Vec2f> proj;
proj.emplace_back(trianglef[0]);
Points proj;
proj.emplace_back(triangle.points[0]);
Point a(proj.back());
Point b(proj.back());
float last_z = facet[0].z();
// Projections of triangle sides intersections with slices.
// a moves along one side, b tracks the other.
Vec2f a(proj.back());
Vec2f b(proj.back());
bool passed_first = false;
bool stop = false;
// Project a sub-triangle on all slices intersecting the triangle.
while (it != layers.end()) {
while (it != layers().end()) {
const float z = (*it)->slice_z;
if (z > z_heights[1] && ! passed_first) {
a = triangle.points[1];
ta = triangle.points[2]-triangle.points[1];
ta *= 1./(z_heights[2] - z_heights[1]);
proj.push_back(a);
// If the middle vertex was already passed, append the vertex
// and make it track the remaining side.
if (z > facet[1].z() && ! passed_first) {
proj.push_back(trianglef[1]);
a = trianglef[1];
ta = trianglef[2]-trianglef[1];
ta *= 1./(facet[2].z() - facet[1].z());
passed_first = true;
}
a += ta * (z-last_z);
if (z > z_heights[2] || it+1 == layers.end()) {
b = triangle.points[2];
// Move a along the side it currently tracks to get
// projected intersection with current slice.
a = passed_first ? (trianglef[1]+ta*(z-facet[1].z()))
: (trianglef[0]+ta*(z-facet[0].z()));
// This slice is above the triangle already.
if (z > facet[2].z() || it+1 == layers().end()) {
b = trianglef[2];
proj.push_back(b);
stop = true;
}
else {
b += tb * (z-last_z);
proj.push_back(a+ta);
b = trianglef[0]+tb*(z-facet[0].z());
proj.push_back(a);
proj.push_back(b+tb);
}
if (it != layers.begin())
expolys[it-layers.begin()-1].emplace_back(proj);
if (it != layers().begin()) {
Points pts;
for (const Vec2f& pt : proj)
pts.emplace_back(scale_(pt.x()), scale_(pt.y()));
expolys[it-layers().begin()-1].emplace_back(pts);
}
if (stop)
break;
// Use a and b as first two points of the polygon
// for the next layer.
proj.clear();
proj.push_back(b);
proj.push_back(a);
++it;
last_z = z;
}
}
}