21 lines
693 B
C++
21 lines
693 B
C++
#include "Implicit.hpp"
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double ImplicitSurface::operator()(const Point& pt) const {
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return operator()(pt.x, pt.y, pt.z);
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}
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Point ImplicitSurface::normal_at(const Point& pt) const {
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// this is simply the gradient.
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static const double d_dist = 1e-8;
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Point normal(
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(operator()(pt.x + d_dist, pt.y, pt.z) -
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operator()(pt.x - d_dist, pt.y, pt.z)) / (2. * d_dist),
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(operator()(pt.x, pt.y + d_dist, pt.z) -
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operator()(pt.x, pt.y - d_dist, pt.z)) / (2. * d_dist),
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(operator()(pt.x, pt.y, pt.z + d_dist) -
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operator()(pt.x, pt.y, pt.z - d_dist)) / (2. * d_dist));
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normal.normalize();
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return normal;
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}
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