std::pair<std::vector<TaggedLine>, std::vector<TaggedLine>>
BSPTree::makeLines(Communicator *, time_t, const std::vector<TaggedLine> &lines, BSPNode *base) {
std::vector<TaggedLine> leftlines;
std::vector<TaggedLine> rightlines;
// for optimization of the tree (this reduced a six-minute gen time to a 38 second gen time)
int chosen = -1;
if (lines.size() > 3) {
chosen = BSPTree::pickMidpointLine(lines, base->m_parent);
} else {
chosen = pafrand() % lines.size();
}
Line chosenLine = lines[chosen].line;
int chosenTag = lines[chosen].tag;
base->setLine(chosenLine);
base->setTag(chosenTag);
Point2f v0 = chosenLine.end() - chosenLine.start();
v0.normalise();
for (size_t i = 0; i < lines.size(); i++) {
if (i == static_cast<unsigned int>(chosen)) {
continue;
}
const Line &testline = lines[i].line;
int tag = lines[i].tag;
Point2f v1 = testline.start() - chosenLine.start();
v1.normalise();
Point2f v2 = testline.end() - chosenLine.start();
v2.normalise();
// should use approxeq here:
double a = testline.start() == chosenLine.start() ? 0 : det(v0, v1);
double b = testline.end() == chosenLine.start() ? 0 : det(v0, v2);
// note sure what to do if a == 0 and b == 0 (i.e., it's parallel... this test at least ensures on the line is
// one or the other side)
if (a >= 0 && b >= 0) {
leftlines.push_back(TaggedLine(testline, tag));
} else if (a <= 0 && b <= 0) {
rightlines.push_back(TaggedLine(testline, tag));
} else {
Point2f p = intersection_point(chosenLine, testline);
Line x = Line(testline.start(), p);
Line y = Line(p, testline.end());
if (a >= 0) {
if (x.length() > 0.0) // should use a tolerance here too
leftlines.push_back(TaggedLine(x, tag));
if (y.length() > 0.0) // should use a tolerance here too
rightlines.push_back(TaggedLine(y, tag));
} else {
if (x.length() > 0.0) // should use a tolerance here too
rightlines.push_back(TaggedLine(x, tag));
if (y.length() > 0.0) // should use a tolerance here too
leftlines.push_back(TaggedLine(y, tag));
}
}
}
return std::make_pair(leftlines, rightlines);
}
int main()
{
double tcrit = intersection_point();
printf("Result: %.12f\n", tcrit);
printf("True: %.12f\n", M_PI/6.);
printf("Error: %e\n", fabs(tcrit - M_PI/6.));
return 0;
}
void closest_point(point2d p, line l, point2d *cp)
{
if (fabs(l.b) <= EPSILON) { // vertical line
cp->x = -l.c;
cp->y = p.y;
return;
}
if (fabs(l.a) <= EPSILON) { // horizontal line
cp->x = p.x;
cp->y = -l.c;
return;
}
// line with slope
line perp; // perpendicular to l through (x,y)
point_and_slope_to_line(p, 1/l.a, &perp);
intersection_point(l, perp, cp);
}
bool segments_intersect(segment s1, segment s2) {
line l1, l2; /* lines containing the input segments */
point p; /* intersection point */
points_to_line(s1.p1, s1.p2, &l1);
points_to_line(s2.p1, s2.p2, &l2);
if(same_lineQ(l1, l2)) /* overlapping or disjoint segments */
return( point_in_box(s1.p1, s2.p1, s2.p2) ||
point_in_box(s1.p2, s2.p1, s2.p2) ||
point_in_box(s2.p1, s1.p1, s1.p2) ||
point_in_box(s2.p2, s1.p1, s1.p2) );
if(parallelQ(l1, l2)) return(FALSE);
intersection_point(l1, l2, p);
return( point_in_box(p, s1.p1, s1.p2) && point_in_box(p, s2.p1, s2.p2) );
}
bool segments_intersect(segment s1, segment s2)
{
line l1, l2;
points_to_line(s1.p1, s1.p2, &l1);
points_to_line(s2.p1, s2.p2, &l2);
if (same_lineQ(l1, l2))
return (point_in_box(s1.p1, s2.p1, s2.p2) ||
point_in_box(s1.p2, s2.p1, s2.p2) ||
point_in_box(s2.p1, s1.p1, s1.p2) ||
point_in_box(s2.p1, s1.p1, s1.p2) );
if (parallelQ(l1, l2))
return false;
point2d p; // intersection point
intersection_point(l1, l2, p);
return (point_in_box(p, s1.p1, s1.p2) && point_in_box(p, s2.p1, s2.p2) );
}
void closest_point(const point p_in, line l, point p_c) {
line perp; /* perpendicular to l through (x,y) */
if(fabs(l.b) <= EPSILON) { /* vertical line */
p_c[X] = -(l.c);
p_c[Y] = p_in[Y];
return;
}
if(fabs(l.a) <= EPSILON) { /* horizontal line */
p_c[X] = p_in[X];
p_c[Y] = -(l.c);
return;
}
point_and_slope_to_line(p_in, 1/l.a, &perp); /* non-degenerate line */
/*printf("perpendicular bisector "); print_line(perp);*/
intersection_point(l, perp, p_c);
/*printf("closest point "); print_point(p_c);*/
}
void FaceOffDriver::set_predicted_vertex_positions( const SurfTrack& surf,
std::vector<Vec3d>& new_positions,
double current_t,
double& adaptive_dt )
{
const NonDestructiveTriMesh& mesh = surf.m_mesh;
std::vector<double> triangle_areas;
triangle_areas.reserve(mesh.num_triangles());
std::vector<Vec3d> triangle_normals;
triangle_normals.reserve(mesh.num_triangles());
std::vector<Vec3d> triangle_centroids;
triangle_centroids.reserve(mesh.num_triangles());
std::vector<double> triangle_plane_distances;
triangle_plane_distances.reserve(mesh.num_triangles());
const std::vector<Vec3st>& tris = mesh.get_triangles();
for ( size_t i = 0; i < tris.size(); ++i )
{
if ( tris[i][0] == tris[i][1] )
{
triangle_areas.push_back( 0 );
triangle_normals.push_back( Vec3d(0,0,0) );
triangle_centroids.push_back( Vec3d(0,0,0) );
}
else
{
triangle_areas.push_back( surf.get_triangle_area( i ) );
triangle_normals.push_back( surf.get_triangle_normal( i ) );
triangle_centroids.push_back( (surf.get_position(tris[i][0]) + surf.get_position(tris[i][1]) + surf.get_position(tris[i][2])) / 3 );
}
double switch_speed = (current_t >= 1.0) ? -speed : speed;
triangle_plane_distances.push_back( adaptive_dt * switch_speed );
}
std::vector<Vec3d> displacements;
displacements.resize( surf.get_num_vertices() );
//
// Null space smoothing
//
{
for ( size_t i = 0; i < surf.get_num_vertices(); ++i )
{
const MeshSmoother& smoother = surf.m_smoother;
smoother.null_space_smooth_vertex( i, triangle_areas, triangle_normals, triangle_centroids, displacements[i] );
}
}
//
// Primary space displacement
//
for ( size_t p = 0; p < surf.get_num_vertices(); ++p )
{
Vec3d normal_dispacement;
intersection_point( triangle_normals, triangle_plane_distances, triangle_areas, mesh.m_vertex_to_triangle_map[p], normal_dispacement );
displacements[p] += normal_dispacement;
//
// Entropy solution
//
if ( surf.m_mesh.m_vertex_to_triangle_map[p].empty() )
{
continue;
}
double sum_mu_l = 0, sum_mu = 0;
const std::vector<size_t>& incident_triangles = mesh.m_vertex_to_triangle_map[p];
for ( size_t j = 0; j < incident_triangles.size(); ++j )
{
size_t triangle_index = incident_triangles[j];
const Vec3st& tri = surf.m_mesh.get_triangle( triangle_index );
Vec3d edge_vector;
if ( tri[0] == p )
{
edge_vector = surf.get_position(tri[1]) - surf.get_position(tri[2]);
}
else if ( tri[1] == p )
{
edge_vector = surf.get_position(tri[2]) - surf.get_position(tri[0]);
}
else
{
edge_vector = surf.get_position(tri[0]) - surf.get_position(tri[1]);
}
Vec3d s = cross( triangle_normals[triangle_index], edge_vector ); // orthogonal to normal and edge oposite vertex
bool contracting = dot( s, displacements[p] ) >= 0.0;
double cos_theta = dot( triangle_normals[triangle_index], normal_dispacement ) / mag(normal_dispacement);
double mu = triangle_areas[triangle_index];
if ( contracting )
{
mu *= cos_theta * cos_theta;
}
double li = fabs( triangle_plane_distances[triangle_index] );
if ( contracting )
{
li /= fabs( cos_theta );
}
sum_mu_l += mu * li;
sum_mu += mu;
}
double length = sum_mu_l / sum_mu;
displacements[p] += length * normal_dispacement / mag(normal_dispacement);
}
double beta = MeshSmoother::compute_max_timestep_quadratic_solve( surf.m_mesh.get_triangles(), surf.get_positions(), displacements, false );
adaptive_dt *= beta;
for(size_t i = 0; i < surf.get_num_vertices(); i++)
{
new_positions[i] = surf.get_position(i) + beta * displacements[i];
}
}
main()
{
point p1,p2,q1,q2,i;
line l1,l2;
segment s1,s2,s3,s4;
while ( scanf("%lf %lf",&p1[X],&p1[Y]) != EOF ) {
scanf("%lf %lf",&p2[X],&p2[Y]);
scanf("%lf %lf",&q1[X],&q1[Y]);
scanf("%lf %lf",&q2[X],&q2[Y]);
/*
print_point(p1);
print_point(p2);
print_point(q1);
print_point(q2);
*/
points_to_segment(p1,p2,&s1);
points_to_segment(q1,q2,&s2);
points_to_line(p1,p2,&l1);
points_to_line(q1,q2,&l2);
print_segment(s1);
print_segment(s2);
/*
printf("slope and line tests\n");
point_and_slope_to_line(p1,-l1.a,&l3);
print_line(l3);
point_and_slope_to_line(p2,-l1.a,&l3);
print_line(l3);
point_and_slope_to_line(q1,-l2.a,&l3);
print_line(l3);
point_and_slope_to_line(q2,-l2.a,&l3);
print_line(l3);
*/
printf("segments_intersect test\n");
printf("%d\n", segments_intersect(s1,s2));
printf("intersection point\n");
intersection_point(l1,l2,i);
print_point(i);
/*
printf("closest point\n");
closest_point(p1,l1,i);
print_point(i);
closest_point(p2,l1,i);
print_point(i);
closest_point(q1,l1,i);
print_point(i);
closest_point(q2,l1,i);
print_point(i);
closest_point(p1,l2,i);
print_point(i);
closest_point(p2,l2,i);
print_point(i);
closest_point(q1,l2,i);
print_point(i);
closest_point(q2,l2,i);
print_point(i);
*/
printf("--------------------------------\n");
}
}
