77 lines
2.2 KiB
C++
77 lines
2.2 KiB
C++
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#include "Box.h"
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#include "util/Solver.h"
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#include <math.h>
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#include <iostream>
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using namespace std;
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#define FP_EQUAL(x,y) (fabs((x)-(y)) < 0.000001)
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Box::Box(refptr<Vector> size)
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{
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m_size = *size;
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m_size[0] = fabs(m_size[0]) / 2.0;
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m_size[1] = fabs(m_size[1]) / 2.0;
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m_size[2] = fabs(m_size[2]) / 2.0;
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}
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Shape::IntersectList Box::intersect(const Ray & ray)
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{
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Ray ray_inv = m_inverse.transform_ray(ray);
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IntersectList res;
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/*
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* Ray equation: R = R0 + tRd
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* x = R0x + tRdx
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* y = R0y + tRdy
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* z = R0z + tRdz
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* Side equation: x - size_x = 0
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* Combined: R0x + (t)Rdx - size_x = 0
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*/
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for (int dim = 0; dim < 3; dim++)
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{
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for (int side = -1; side <= 1; side += 2)
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{
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LinearSolver solver(ray_inv.getDirection()[dim],
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ray_inv.getOrigin()[dim]
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+ side * m_size[dim]);
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Solver::Result solutions = solver.solve();
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for (int i = 0; i < solutions.numResults; i++)
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{
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if (solutions.results[i] >= 0.0)
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{
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Vector isect_point = ray_inv[solutions.results[i]];
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if ( (dim == 0 || fabs(isect_point[0]) <= m_size[0])
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&& (dim == 1 || fabs(isect_point[1]) <= m_size[1])
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&& (dim == 2 || fabs(isect_point[2]) <= m_size[2]) )
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{
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res.push_back(m_transform.transform_point(isect_point));
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}
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}
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}
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}
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}
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return res;
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}
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Vector Box::getNormalAt(const Vector & pt)
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{
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Vector local_pt = m_inverse.transform_point(pt);
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Vector normal(0, 0, -1);
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if ( FP_EQUAL(local_pt[0], m_size[0]) )
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normal = Vector(1, 0, 0);
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else if ( FP_EQUAL(local_pt[0], -m_size[0]) )
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normal = Vector(-1, 0, 0);
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else if ( FP_EQUAL(local_pt[1], m_size[1]) )
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normal = Vector(0, 1, 0);
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else if ( FP_EQUAL(local_pt[1], -m_size[1]) )
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normal = Vector(0, -1, 0);
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else if ( FP_EQUAL(local_pt[2], m_size[2]) )
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normal = Vector(0, 0, 1);
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return m_transform.transform_normal(normal);
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}
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