bool
Bface::view_intersect(
CNDCpt& p, // Screen point at which to do intersect
Wpt& nearpt, // Point on face visually nearest to p
double& dist, // Distance from nearpt to ray from camera
double& d2d, // Distance in pixels nearpt to p
Wvec& n // "normal" at nearpt in world coordinates
) const
{
// (Bsimplex virtual method):
// Intersection w/ ray from given screen point -- returns the point
// on the Bface that is nearest to the given screen space point.
// Note: the returned "near point" and "normal" are both
// transformed to world space.
// Get "eye point" for computing distance.
// Not sure if this is the same as cam->from(),
// but it seems to be the way it's done in other
// intersection code.
Wpt eye = XYpt(p);
// Make object-space ray:
Wline ray = mesh()->inv_xform()*Wline(p); // ray in object space
Wpt hit;
// Try for exact intersection:
double d;
if (ray_intersect(ray, hit, d)) {
// Direct hit
nearpt = mesh()->xform()*hit;
dist = nearpt.dist(eye);
d2d = PIXEL(nearpt).dist(PIXEL(p));
n = (mesh()->inv_xform().transpose()*norm()).normalized();
return true;
}
Wpt hit1, hit2, hit3;
double d1 = DBL_MAX, d2 = DBL_MAX, d3 = DBL_MAX;
Wvec n1, n2, n3;
_e1->view_intersect(p, hit1, d, d1, n1);
_e2->view_intersect(p, hit2, d, d2, n2);
_e3->view_intersect(p, hit3, d, d3, n3);
// Rename so d1 represents closest hit
if (d1 > d2) {
swap(d1, d2);
swap(hit1, hit2);
swap(n1, n2);
}
if (d1 > d3) {
swap(d1, d3);
swap(hit1, hit3);
swap(n1, n3);
}
nearpt = mesh()->xform()*hit1;
dist = nearpt.dist(eye);
d2d = PIXEL(nearpt).dist(PIXEL(p));
n = n1;
return true;
}
Wpt
QuadtreeNode::farthest_pt(Wpt& p)
{
Wpt ret = _v1;
double max_dist = ret.dist(p);
if (_v2.dist(p) > max_dist) {
ret = _v2;
max_dist = ret.dist(p);
}
if (_v3.dist(p) > max_dist) {
ret = _v3;
}
return ret;
}
bool
Bedge::view_intersect(
CNDCpt& p, // Screen point at which to do intersect
Wpt& nearpt, // Point on edge visually nearest to p
double& dist, // Distance from nearpt to ray from camera
double& d2d, // Distance in pixels nearpt to p
Wvec& n // "normal" at nearpt in world space
) const
{
// (Bsimplex virtual method):
// Intersection w/ ray from given screen point -- returns the point
// on the Bedge that is nearest to the given screen space point.
// Note: the returned "near point" and "normal" are both
// transformed to world space.
// Find nearest point on the edge in screen-space, and make a 3D
// ray out of it (world space, not object space):
Wline ray(NDCline(_v1->ndc(), _v2->ndc()).project_to_seg(p));
// Working in world space (applying mesh xf to verts), find
// nearest point on the edge to the ray:
nearpt = Wline(_v1->wloc(), _v2->wloc()).project_to_seg(ray);
// Compute world and screen distances
dist = nearpt.dist(ray.point());
d2d = PIXEL(nearpt).dist(PIXEL(ray.point()));
// Return a "normal" vector:
Wvec n1;
if (nfaces() == 2)
n1 = norm();
else if (nfaces() == 1)
n1 = get_face()->norm();
else
n1 = (ray.point() - nearpt).normalized();
// Transform the normal properly:
n = (_mesh->inv_xform().transpose()*n1).normalized();
return 1;
}
//! Given an initial slash gesture (or delayed slash) near the
//! center of an existing straight Bcurve, set up the widget to
//! do a sweep cross-ways to the Bcurve:
bool
SWEEP_LINE::setup(CGESTUREptr& slash, double dur)
{
static bool debug =
Config::get_var_bool("DEBUG_SWEEP_SETUP",false) || debug_all;
err_adv(debug, "SWEEP_LINE::setup");
// check the gesture
if (!(slash && slash->straightness() > 0.99)) {
err_adv(debug, "SWEEP_LINE::setup: gesture is bad");
return false;
}
// find the (straight) Bcurve near slash start
_curve = Bcurve::hit_ctrl_curve(slash->start());
if (!(_curve && _curve->is_straight())) {
err_adv(debug, "SWEEP_LINE::setup: no straight curve at start");
return false;
}
// find endpoints
Bpoint *b1 = _curve->b1(), *b2 = _curve->b2();
assert(b1 && b2); // straight curve must have endpoints
// curve cannot be connected to other curves
if (b1->vert()->degree() != 1 || b2->vert()->degree() != 1) {
err_adv(debug, "SWEEP_LINE::setup: curve is not isolated");
return false;
}
// ensure the gesture starts near the center of the straight line Bcurve:
{
PIXEL a = b1->vert()->pix();
PIXEL b = b2->vert()->pix();
double t = (slash->start() - a).tlen(b-a);
if (t < 0.35 || t > 0.65) {
err_adv(debug, "SWEEP_LINE::setup: gesture not near center of line");
return false;
}
}
// find the plane to work in
_plane = check_plane(shared_plane(b1, b2));
if (!_plane.is_valid()) {
err_adv(debug, "SWEEP_LINE::setup: no valid plane");
return false;
}
// check that slash is perpendicular to line
Wpt a = b1->loc(); // endpoint at b1
Wpt b = b2->loc(); // endpoint at b2
Wvec t = b - a; // vector from endpt a to endpt b
Wpt o = a + t/2; // center of straight line curve
Wvec n = cross(_plane.normal(), t); // direction across line ab
Wvec slash_vec = endpt_vec(slash, _plane);
const double ALIGN_ANGLE_THRESH = 15;
double angle = rad2deg(slash_vec.angle(n));
if (angle > 90) {
angle = 180 - angle;
n = -n;
}
if (angle > ALIGN_ANGLE_THRESH) {
err_adv(debug, "SWEEP_LINE::setup: slash is not perpendicular to line");
err_adv(debug, " angle: %f", angle);
return false;
}
// compute guideline endpoint:
Wpt endpt = o + n.normalized()*a.dist(b);
return SWEEP_BASE::setup(_curve->mesh(), o, endpt, dur);
}
