Intersection Cone::Intercepta(const Raio& r_vis, IntersectionMode mode, float threshold)
{
float a, b, c, delta;
Intersection intersection;
// valores intermediários
Vetor_3D K = Vetor_3D(r_vis.X0() - centro.X(),
r_vis.Y0() - centro.Y(),
r_vis.Z0() - centro.Z());
// montando a equação do 2º grau at2 + bt + c = 0
// equação para o cone:
a = pow(r_vis.Direcao().X(), 2) + pow(r_vis.Direcao().Z(), 2) - pow(r_vis.Direcao().Z(), 2);
b = 2*((r_vis.Direcao().X() * K.X()) + (r_vis.Direcao().Z() * K.Y()) - (r_vis.Direcao().Z() * K.Z));
c = pow(K.X(), 2) + pow(K.Y(), 2) - pow(K.Z(), 2);
delta = b*b - 4*a*c;
if (delta >= 0) {
float t_plus = (-b + sqrt(delta)) /(2*a);
float t_minus = (-b - sqrt(delta)) /(2*a);
Ponto_3D p_plus( r_vis.Origem().X() + r_vis.Direcao().X()*t_plus ,
r_vis.Origem().Y() + r_vis.Direcao().Y()*t_plus ,
r_vis.Origem().Z() + r_vis.Direcao().Z()*t_plus );
Ponto_3D p_minus( r_vis.Origem().X() + r_vis.Direcao().X()*t_minus ,
r_vis.Origem().Y() + r_vis.Direcao().Y()*t_minus ,
r_vis.Origem().Z() + r_vis.Direcao().Z()*t_minus );
bool p_plus_dentro_do_intervalo = false;
bool p_minus_dentro_do_intervalo = false;
if ((p_plus.Y() < (centro.Y() + altura/2.0)) && (p_minus.Y() > (centro.Y() - altura/2.0)))
p_plus_dentro_do_intervalo = true;
if ((p_minus.Y() < (centro.Y() + altura/2.0)) && (p_minus.Y() > (centro.Y() - altura/2.0)))
p_minus_dentro_do_intervalo = true;
if (p_plus_dentro_do_intervalo && p_minus_dentro_do_intervalo){
intersection = Intersection::nearest(
Intersection(this, t_plus),
Intersection(this, t_minus), threshold);
} else if (p_plus_dentro_do_intervalo){
intersection.setValues(this, t_plus);
} else if (p_minus_dentro_do_intervalo){
intersection.setValues(this, t_minus);
}
}
return intersection;
}
static Term
eval2(Int fi, Term t1, Term t2 USES_REGS) {
arith2_op f = fi;
switch (f) {
case op_plus:
return p_plus(t1, t2 PASS_REGS);
case op_minus:
return p_minus(t1, t2 PASS_REGS);
case op_times:
return p_times(t1, t2 PASS_REGS);
case op_div:
return p_div(t1, t2 PASS_REGS);
case op_idiv:
return p_div2(t1, t2 PASS_REGS);
case op_and:
return p_and(t1, t2 PASS_REGS);
case op_or:
return p_or(t1, t2 PASS_REGS);
case op_sll:
return p_sll(t1, t2 PASS_REGS);
case op_slr:
return p_slr(t1, t2 PASS_REGS);
case op_mod:
return p_mod(t1, t2 PASS_REGS);
case op_rem:
return p_rem(t1, t2 PASS_REGS);
case op_fdiv:
return p_fdiv(t1, t2 PASS_REGS);
case op_xor:
return p_xor(t1, t2 PASS_REGS);
case op_atan2:
return p_atan2(t1, t2 PASS_REGS);
case op_power:
return p_exp(t1, t2 PASS_REGS);
case op_power2:
return p_power(t1, t2 PASS_REGS);
case op_gcd:
return p_gcd(t1, t2 PASS_REGS);
case op_min:
return p_min(t1, t2);
case op_max:
return p_max(t1, t2);
case op_rdiv:
return p_rdiv(t1, t2 PASS_REGS);
}
RERROR();
}
Point<float> GMWMI_finder::get_normal (const Point<float>& p, Interp& interp) const
{
Point<float> normal (0.0, 0.0, 0.0);
for (size_t axis = 0; axis != 3; ++axis) {
Point<float> p_minus (p);
p_minus[axis] -= 0.5 * GMWMI_PERTURBATION;
const Tissues v_minus = get_tissues (p_minus, interp);
Point<float> p_plus (p);
p_plus[axis] += 0.5 * GMWMI_PERTURBATION;
const Tissues v_plus = get_tissues (p_plus, interp);
normal[axis] = (v_plus.get_wm() - v_plus.get_gm()) - (v_minus.get_wm() - v_minus.get_gm());
}
return (normal.normalise());
}
Point<float> GMWMI_finder::get_cf_min_step (const Point<float>& p, Interp& interp) const
{
Point<float> grad (0.0, 0.0, 0.0);
for (size_t axis = 0; axis != 3; ++axis) {
Point<float> p_minus (p);
p_minus[axis] -= 0.5 * GMWMI_PERTURBATION;
const Tissues v_minus = get_tissues (p_minus, interp);
Point<float> p_plus (p);
p_plus[axis] += 0.5 * GMWMI_PERTURBATION;
const Tissues v_plus = get_tissues (p_plus, interp);
if (!v_minus.valid() || !v_plus.valid())
return Point<float> (0.0, 0.0, 0.0);
grad[axis] = (v_plus.get_gm() - v_plus.get_wm()) - (v_minus.get_gm() - v_minus.get_wm());
}
grad *= (1.0 / GMWMI_PERTURBATION);
if (!grad.norm2())
return Point<float> (0.0, 0.0, 0.0);
const Tissues local_tissue = get_tissues (p, interp);
const float diff = local_tissue.get_gm() - local_tissue.get_wm();
Point<float> step = -grad * (diff / grad.norm2());
const float norm = step.norm();
if (norm > 0.5 * min_vox)
step *= 0.5 * min_vox / norm;
return step;
}