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geom.cc
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geom.cc
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// Example ray tracing program
// Written by Paolo Bonzini, 2005
#include <cmath>
#include <cstdlib>
#include "config.h"
#include "v3d.h"
#include "geom.h"
real Intersection::inf = INFINITY;
Entity::~Entity ()
{
}
bool Plane::inside (const Point3D &p) const
{
return Vector3D (p) * normal + d >= 0;
}
bool Plane::intersect (Intersection &i, const Object &o, real tlim) const
{
const NormRay3D &r = i.r;
real denom = r.dir * normal;
if (denom == 0.0)
return false;
real t = -(Vector3D (r.source) * normal + d) / denom;
if (t > tlim && t < i.t)
{
i.t = t;
i.entity = this;
i.object = &o;
return true;
}
else
return false;
}
real Plane::texture_u (const Point3D &p) const
{
Vector3D v (normal.y, -normal.x, normal.z);
return (p * v);
}
real Plane::texture_v (const Point3D &p) const
{
Vector3D v (normal.x, -normal.z, normal.y);
return (p * v);
}
UnitVector3D Plane::get_normal (const Point3D &p) const
{
return normal;
}
UnitVector3D Plane::get_normal (const Intersection &i) const
{
return normal;
}
bool Sphere::inside (const Point3D &p) const
{
Vector3D delta = p - center;
return delta * delta <= r2;
}
bool Sphere::intersect (Intersection &i, const Object &o, real tlim) const
{
const NormRay3D &r = i.r;
Vector3D p_to_center = center - r.source;
real tpp = p_to_center * r.dir;
real tdc2 = r2 - (p_to_center * p_to_center - tpp * tpp);
if (tdc2 < 0.0)
return false;
// Return the point that is in front of the observer, or the closest one.
real tdc = sqrt (tdc2);
bool from_inside = tpp - tdc < tlim;
real t = from_inside ? tpp + tdc : tpp - tdc;
if (t > tlim && t < i.t)
{
i.from_inside = from_inside;
i.t = t;
i.entity = this;
i.object = &o;
return true;
}
else
return false;
}
UnitVector3D Sphere::get_normal (const Point3D &p) const
{
return UnitVector3D ((p - center) / r);
}
real Sphere::texture_u (const Point3D &p) const
{
real dx = p.x - center.x;
real dz = p.z - center.z;
return atan2 (dz, dx) / M_PI;
}
real Sphere::texture_v (const Point3D &p) const
{
real dx = p.x - center.x;
real dy = p.y - center.y;
real dz = p.z - center.z;
return atan2 (dy, hypot (dx, dz)) / M_PI;
}
bool ReverseSphere::inside (const Point3D &p) const
{
Vector3D delta = p - center;
return delta * delta >= r2;
}
UnitVector3D ReverseSphere::get_normal (const Point3D &p) const
{
return UnitVector3D ((center - p) / r);
}
UnitVector3D CSGEntity::get_normal (const Intersection &i) const
{
std::abort ();
}
UnitVector3D CSGEntity::get_normal (const Point3D &p) const
{
std::abort ();
}
real CSGEntity::texture_u (const Point3D &p) const
{
std::abort ();
}
real CSGEntity::texture_v (const Point3D &p) const
{
std::abort ();
}
bool BoundingBox::inside (const Point3D &p) const
{
return bbox.inside (p) && obj.inside (p);
}
bool BoundingBox::intersect (Intersection &i, const Object &o, real tlim) const
{
Intersection i1 (i.r);
return (bbox.intersect (i1, o, tlim) || bbox.inside (i.r.source))
&& obj.intersect (i, o, tlim);
}
bool Difference::inside (const Point3D &p) const
{
return obj.inside (p) && !bite.inside (p);
}
bool Difference::intersect (Intersection &i, const Object &o, real tlim) const
{
Intersection i1 (i);
bool had_intersection = obj.intersect (i1, o, tlim);
if (!had_intersection)
return false;
// controllare...
Point3D p = i1.r (i1.t);
if (bite.inside (p))
return bite.intersect (i, o, i1.t);
i = i1;
return true;
}
bool Union::inside (const Point3D &p) const
{
return obj.inside (p) || next.inside (p);
}
bool Union::intersect (Intersection &i, const Object &o, real tlim) const
{
bool had_intersection = obj.intersect (i, o, tlim);
const Union *this_union = this;
while (this_union->next_is_union)
{
this_union = static_cast <const Union *> (&next);
had_intersection |= this_union->obj.intersect (i, o, tlim);
}
return had_intersection | this_union->next.intersect (i, o, tlim);
}