112 lines
3.2 KiB
C++
112 lines
3.2 KiB
C++
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#include "Subtract.h"
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#include <iostream>
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using namespace std;
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Subtract::Subtract(const vector< refptr<Shape> > & shapes)
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{
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int num_shapes = shapes.size();
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if (num_shapes > 2)
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{
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m_shape2 = shapes[num_shapes - 1];
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vector< refptr<Shape> > rest = shapes;
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rest.pop_back();
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m_shape1 = new Subtract(rest);
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}
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else if (num_shapes == 2)
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{
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m_shape1 = shapes[0];
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m_shape2 = shapes[1];
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}
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else
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{
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cerr << __FILE__ << ": " << __LINE__
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<< ": error: Subtract::Subtract() called with only "
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<< num_shapes
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<< " sub-shapes!"
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<< endl;
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exit(4);
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}
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}
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Shape::IntersectionList Subtract::intersect(refptr<Shape> _this, const Ray & ray)
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{
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Ray ray_inv = m_inverse.transform_ray(ray);
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IntersectionList res1 = m_shape1->intersect(m_shape1, ray_inv);
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if (res1.size() == 0) /* optimization */
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return res1;
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IntersectionList res2 = m_shape2->intersect(m_shape2, ray_inv);
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BoolIntersectionList merged(res1, res2, ray_inv.getOrigin());
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IntersectionList res;
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bool in1 = false, in2 = false;
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/* initially go through the merged intersections to see whether
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* the ray started inside one of the sub-objects */
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for (int i = 0, sz = merged.size(), saw1 = 0, saw2 = 0;
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i < sz && (!saw1 || !saw2);
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i++)
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{
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Vector normal = merged[i].intersection.normal;
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double dot = - (ray_inv.getDirection() % normal);
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bool back = dot < 0.0;
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bool left = merged[i].left;
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if (back)
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{
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if (left && !saw1)
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in1 = true;
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else if (!left && !saw2)
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in2 = true;
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}
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if (left)
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saw1 = 1;
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else
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saw2 = 1;
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}
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bool in_bool = in1 && !in2;
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for (int i = 0, sz = merged.size(); i < sz; i++)
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{
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Vector normal = merged[i].intersection.normal;
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double dot = - (ray_inv.getDirection() % normal);
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bool front = dot > 0.0;
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bool left = merged[i].left;
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if (left)
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in1 = front;
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else
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in2 = front;
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if (!in_bool && in1 && !in2)
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{
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/* we found an intersection point
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* to get into the boolean object */
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in_bool = true;
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BoolIntersection bi = merged[i];
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Intersection i = bi.intersection;
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if ( ! left ) /* if this point came from object B (A - B) */
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i.normal = - i.normal;
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res.add(i.transform(m_transform));
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}
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else if (in_bool && !(in1 && !in2))
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{
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/* we found an intersection point
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* to get out of the boolean object */
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BoolIntersection bi = merged[i];
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Intersection i = bi.intersection;
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if ( ! left ) /* if this point came from object B (A - B) */
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i.normal = - i.normal;
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res.add(i.transform(m_transform));
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in_bool = false;
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}
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}
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return res;
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}
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refptr<Shape> Subtract::clone()
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{
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Subtract * s = new Subtract(*this);
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s->m_shape1 = m_shape1->clone();
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s->m_shape2 = m_shape2->clone();
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return refptr<Shape>(s);
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}
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