void Torus::ObjectSpace_AppendAllIntersections(
const Vector& vantage,
const Vector& direction,
IntersectionList& intersectionList) const
{
double u[4];
const int numSolutions = SolveIntersections(vantage, direction, u);
for (int i=0; i < numSolutions; ++i)
{
Intersection intersection;
const Vector disp = u[i] * direction;
intersection.point = vantage + disp;
intersection.distanceSquared = disp.MagnitudeSquared();
intersection.surfaceNormal = SurfaceNormal(intersection.point);
intersection.solid = this;
intersectionList.push_back(intersection);
}
}
void Spheroid::ObjectSpace_AppendAllIntersections(
const Vector& vantage,
const Vector& direction,
IntersectionList& intersectionList) const
{
double u[2];
const int numSolutions = Algebra::SolveQuadraticEquation(
b2*c2*direction.x*direction.x + a2*c2*direction.y*direction.y + a2*b2*direction.z*direction.z,
2.0*(b2*c2*vantage.x*direction.x + a2*c2*vantage.y*direction.y + a2*b2*vantage.z*direction.z),
b2*c2*vantage.x*vantage.x + a2*c2*vantage.y*vantage.y + a2*b2*vantage.z*vantage.z - a2*b2*c2,
u
);
for (int i=0; i < numSolutions; ++i)
{
if (u[i] > EPSILON)
{
Intersection intersection;
Vector displacement = u[i] * direction;
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.point = vantage + displacement;
// The surface normal vector was calculated by expressing the spheroid as a
// function z(x,y) = sqrt(1 - (x/a)^2 - (y/b)^2),
// taking partial derivatives dz/dx = (c*c*x)/(a*a*z), dz/dy = (c*c*y)/(b*b*z),
// and using these to calculate the vectors <1, 0, dz/dx> and <0, 1, dy,dz>.
// The normalized cross product of these two vectors yields the surface normal vector.
const double x = intersection.point.x;
const double y = intersection.point.y;
const double z = intersection.point.z;
// But we need to handle special cases when z is very close to 0.
if (fabs(z) <= EPSILON)
{
if (fabs(x) <= EPSILON)
{
// The equation devolves to (y^2)/(b^2) = 1, or y = +/- b.
intersection.surfaceNormal = Vector(0.0, ((y > 0.0) ? 1.0 : -1.0), 0.0);
}
else
{
// The equation devolves to an ellipse on the xy plane :
// (x^2)/(a^2) + (y^2)/(b^2) = 1.
intersection.surfaceNormal = Vector(-1.0, -(a2*y)/(b2*x), 0.0).UnitVector();
}
}
else
{
intersection.surfaceNormal = Vector((c2*x)/(a2*z), (c2*y)/(b2*z), 1.0).UnitVector();
}
// Handle special cases with polarity: the polarity of the components of
// the surface normal vector must match that of the <x,y,z> intersection point,
// because the surface normal vector always points (roughly) away from the vantage, just
// like any point on the surface of the spheroid does.
if (x * intersection.surfaceNormal.x < 0.0) // negative product means opposite polarities
{
intersection.surfaceNormal.x *= -1.0;
}
if (y * intersection.surfaceNormal.y < 0.0) // negative product means opposite polarities
{
intersection.surfaceNormal.y *= -1.0;
}
if (z * intersection.surfaceNormal.z < 0.0) // negative product means opposite polarities
{
intersection.surfaceNormal.z *= -1.0;
}
intersection.solid = this;
intersectionList.push_back(intersection);
}
}
}
void TriangleMesh::AppendAllIntersections(
const Vector& vantage,
const Vector& direction,
IntersectionList& intersectionList) const
{
// Iterate through all the triangles in this solid object,
// looking for every intersection.
TriangleList::const_iterator iter = triangleList.begin();
TriangleList::const_iterator end = triangleList.end();
for (; iter != end; ++iter)
{
const Triangle& tri = *iter;
const Vector& aPoint = pointList[tri.a];
const Vector& bPoint = pointList[tri.b];
const Vector& cPoint = pointList[tri.c];
// The variables u, v, w are deliberately left
// uninitialized for efficiency; they are only
// assigned values if we find an intersection.
double u, v, w;
// Sometimes we have to try more than one ordering of the points (A,B,C)
// in order to get a valid solution to the intersection equations.
// Take advantage of C++ short-circuit boolean or "||" operator:
// as soon as one of the function calls returns true, we don't call any more.
if (AttemptPlaneIntersection(vantage, direction, aPoint, bPoint, cPoint, u, v, w) ||
AttemptPlaneIntersection(vantage, direction, bPoint, cPoint, aPoint, u, v, w) ||
AttemptPlaneIntersection(vantage, direction, cPoint, aPoint, bPoint, u, v, w))
{
// We found an intersection of the direction with the plane that passes through the points (A,B,C).
// Figure out whether the intersection point is inside the triangle (A,B,C) or outside it.
// We are interested only in intersections that are inside the triangle.
// The trick here is that the values v,w are fractions that will be 0..1 along the
// line segments AB and BC (or whichever ordered triple of points we found the solution for).
// If we just checked that both v and w are in the range 0..1, we would be finding
// intersections with a parallelogram ABCD, where D is the fourth point that completes the
// parallelogram whose other vertices are ABC.
// But checking instead that v + w <= 1.0 constrains the set of points
// to the interior or border of the triangle ABC.
if ((v >= 0.0) && (w >= 0.0) && (v + w <= 1.0) && (u >= EPSILON))
{
// We have found an intersection with one of the triangular facets!
// Also determine whether the intersection point is in "front" of the vantage (positively along the direction)
// by checking for (u >= EPSILON). Note that we allow for a little roundoff error by checking
// against EPSILON instead of 0.0, because this method is called using vantage = a point on this surface,
// in order to calculate surface lighting, and we don't want to act like the surface is shading itself!
if (u >= EPSILON)
{
// We have found a new intersection to be added to the list.
const Vector displacement = u * direction;
Intersection intersection;
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.point = vantage + displacement;
intersection.surfaceNormal = NormalVector(tri);
intersection.solid = this;
intersection.context = &tri; // remember which triangle we hit, for SurfaceOptics().
intersectionList.push_back(intersection);
}
}
}
}
}
void Cuboid::ObjectSpace_AppendAllIntersections(
const Vector& vantage,
const Vector& direction,
IntersectionList& intersectionList) const
{
double u;
Intersection intersection;
Vector displacement;
// Check for intersections with left/right faces: x = +a or x = -a.
if (fabs(direction.x) > EPSILON)
{
// right face (x = +a)
u = (a - vantage.x) / direction.x;
if (u > EPSILON)
{
displacement = u * direction;
intersection.point = vantage + displacement;
if (ObjectSpace_Contains(intersection.point))
{
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.surfaceNormal = Vector(+1.0, 0.0, 0.0);
intersection.solid = this;
intersection.tag = "right face";
intersectionList.push_back(intersection);
}
}
// left face (x = -a)
u = (-a - vantage.x) / direction.x;
if (u > EPSILON)
{
displacement = u * direction;
intersection.point = vantage + displacement;
if (ObjectSpace_Contains(intersection.point))
{
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.surfaceNormal = Vector(-1.0, 0.0, 0.0);
intersection.solid = this;
intersection.tag = "left face";
intersectionList.push_back(intersection);
}
}
}
// Check for intersections with front/back faces: y = -b or y = +b.
if (fabs(direction.y) > EPSILON)
{
// front face (y = +b)
u = (b - vantage.y) / direction.y;
if (u > EPSILON)
{
displacement = u * direction;
intersection.point = vantage + displacement;
if (ObjectSpace_Contains(intersection.point))
{
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.surfaceNormal = Vector(0.0, +1.0, 0.0);
intersection.solid = this;
intersection.tag = "front face";
intersectionList.push_back(intersection);
}
}
// back face (y = -b)
u = (-b - vantage.y) / direction.y;
if (u > EPSILON)
{
displacement = u * direction;
intersection.point = vantage + displacement;
if (ObjectSpace_Contains(intersection.point))
{
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.surfaceNormal = Vector(0.0, -1.0, 0.0);
intersection.solid = this;
intersection.tag = "back face";
intersectionList.push_back(intersection);
}
}
}
// Check for intersections with top/bottom faces: z = -c or z = +c.
if (fabs(direction.z) > EPSILON)
{
// top face (z = +c)
u = (c - vantage.z) / direction.z;
if (u > EPSILON)
{
displacement = u * direction;
intersection.point = vantage + displacement;
if (ObjectSpace_Contains(intersection.point))
{
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.surfaceNormal = Vector(0.0, 0.0, +1.0);
intersection.solid = this;
intersection.tag = "top face";
intersectionList.push_back(intersection);
}
}
// bottom face (z = -c)
u = (-c - vantage.z) / direction.z;
if (u > EPSILON)
{
displacement = u * direction;
intersection.point = vantage + displacement;
if (ObjectSpace_Contains(intersection.point))
{
intersection.distanceSquared = displacement.MagnitudeSquared();
intersection.surfaceNormal = Vector(0.0, 0.0, -1.0);
intersection.solid = this;
intersection.tag = "bottom face";
intersectionList.push_back(intersection);
}
}
}
}
IntersectionList Sphere::AllIntersections(const Ray& inray) const
{
Ray ray = LorentzTransform(inray, RefFrame);
#define D ray.Direction
#define O ray.Origin
#define S InitialPosition
#define V RefFrame.Velocity
double r1, r2;
{
double tmp181 = (D.x*O.x);
double tmp180 = (-tmp181);
double tmp179 = (D.y*O.y);
double tmp149 = (D.z*O.z);
double tmp176 = (D.x*S.x);
double tmp174 = (D.y*S.y);
double tmp148 = (D.z*S.z);
double tmp139 = (O.t*V.x);
double tmp171 = (D.x*tmp139);
double tmp146 = (O.x*V.x);
double tmp137 = (S.t*V.x);
double tmp168 = (D.x*tmp137);
double tmp91 = (S.x*V.x);
double tmp12 = V.x*V.x;
double tmp143 = (O.t*tmp12);
double tmp85 = (S.t*tmp12);
double tmp57 = (O.t*V.y);
double tmp163 = (D.y*tmp57);
double tmp133 = (O.y*V.y);
double tmp55 = (S.t*V.y);
double tmp160 = (D.y*tmp55);
double tmp69 = (S.y*V.y);
double tmp7 = V.y*V.y;
double tmp130 = (O.t*tmp7);
double tmp63 = (S.t*tmp7);
double tmp122 = (O.t*V.z);
double tmp121 = (D.z*tmp122);
double tmp50 = (O.z*V.z);
double tmp46 = (S.t*V.z);
double tmp118 = (D.z*tmp46);
double tmp39 = (S.z*V.z);
double tmp2 = V.z*V.z;
double tmp115 = (O.t*tmp2);
double tmp32 = (S.t*tmp2);
double tmp147 = (tmp149 - tmp148);
double tmp145 = (tmp147 - tmp146);
double tmp144 = (tmp145 + tmp91);
double tmp142 = (tmp144 - tmp143);
double tmp141 = (tmp142 + tmp85);
double tmp140 = (O.x - S.x);
double tmp138 = (tmp140 + tmp139);
double tmp136 = (tmp138 - tmp137);
double tmp135 = (D.x*tmp136);
double tmp134 = (tmp141 + tmp135);
double tmp132 = (tmp134 - tmp133);
double tmp131 = (tmp132 + tmp69);
double tmp129 = (tmp131 - tmp130);
double tmp128 = (tmp129 + tmp63);
double tmp127 = (O.y - S.y);
double tmp126 = (tmp127 + tmp57);
double tmp125 = (tmp126 - tmp55);
double tmp124 = (D.y*tmp125);
double tmp123 = (tmp128 + tmp124);
double tmp120 = (tmp123 + tmp121);
double tmp119 = (tmp120 - tmp50);
double tmp117 = (tmp119 - tmp118);
double tmp116 = (tmp117 + tmp39);
double tmp114 = (tmp116 - tmp115);
double tmp113 = (tmp114 + tmp32);
double tmp112 = tmp113*tmp113;
double tmp111 = (4 * tmp112);
double tmp110 = O.x*O.x;
double tmp109 = O.y*O.y;
double tmp108 = (tmp110 + tmp109);
double tmp107 = O.z*O.z;
double tmp106 = (tmp108 + tmp107);
double tmp105 = Radius * Radius;
double tmp104 = (tmp106 - tmp105);
double tmp103 = S.x*S.x;
double tmp102 = (tmp104 + tmp103);
double tmp101 = S.y*S.y;
double tmp100 = (tmp102 + tmp101);
double tmp99 = (O.z*S.z);
double tmp98 = (2 * tmp99);
double tmp97 = (tmp100 - tmp98);
double tmp96 = S.z*S.z;
double tmp95 = (tmp97 + tmp96);
double tmp94 = (O.t*tmp91);
double tmp93 = (2 * tmp94);
double tmp92 = (tmp95 - tmp93);
double tmp90 = (S.t*tmp91);
double tmp89 = (2 * tmp90);
double tmp88 = (tmp92 + tmp89);
double tmp35 = O.t*O.t;
double tmp87 = (tmp35*tmp12);
double tmp86 = (tmp88 + tmp87);
double tmp84 = (O.t*tmp85);
double tmp83 = (2 * tmp84);
double tmp82 = (tmp86 - tmp83);
double tmp28 = S.t*S.t;
double tmp81 = (tmp28*tmp12);
double tmp80 = (tmp82 + tmp81);
double tmp79 = (-O.t);
double tmp78 = (tmp79 + S.t);
double tmp77 = (tmp78*V.x);
double tmp76 = (S.x + tmp77);
double tmp75 = (O.x*tmp76);
double tmp74 = (2 * tmp75);
double tmp73 = (tmp80 - tmp74);
double tmp72 = (O.t*tmp69);
double tmp71 = (2 * tmp72);
double tmp70 = (tmp73 - tmp71);
double tmp68 = (S.t*tmp69);
double tmp67 = (2 * tmp68);
double tmp66 = (tmp70 + tmp67);
double tmp65 = (tmp35*tmp7);
double tmp64 = (tmp66 + tmp65);
double tmp62 = (O.t*tmp63);
double tmp61 = (2 * tmp62);
double tmp60 = (tmp64 - tmp61);
double tmp59 = (tmp28*tmp7);
double tmp58 = (tmp60 + tmp59);
double tmp56 = (S.y - tmp57);
double tmp54 = (tmp56 + tmp55);
double tmp53 = (O.y*tmp54);
double tmp52 = (2 * tmp53);
double tmp51 = (tmp58 - tmp52);
double tmp49 = (O.t*tmp50);
double tmp48 = (2 * tmp49);
double tmp47 = (tmp51 + tmp48);
double tmp45 = (O.z*tmp46);
double tmp44 = (2 * tmp45);
double tmp43 = (tmp47 - tmp44);
double tmp42 = (O.t*tmp39);
double tmp41 = (2 * tmp42);
double tmp40 = (tmp43 - tmp41);
double tmp38 = (S.t*tmp39);
double tmp37 = (2 * tmp38);
double tmp36 = (tmp40 + tmp37);
double tmp34 = (tmp35*tmp2);
double tmp33 = (tmp36 + tmp34);
double tmp31 = (O.t*tmp32);
double tmp30 = (2 * tmp31);
double tmp29 = (tmp33 - tmp30);
double tmp27 = (tmp28*tmp2);
double tmp26 = (tmp29 + tmp27);
double tmp20 = D.x*D.x;
double tmp19 = D.y*D.y;
double tmp18 = (tmp20 + tmp19);
double tmp17 = D.z*D.z;
double tmp16 = (tmp18 + tmp17);
double tmp15 = (D.x*V.x);
double tmp14 = (2 * tmp15);
double tmp13 = (tmp16 - tmp14);
double tmp11 = (tmp13 + tmp12);
double tmp10 = (D.y*V.y);
double tmp9 = (2 * tmp10);
double tmp8 = (tmp11 - tmp9);
double tmp6 = (tmp8 + tmp7);
double tmp5 = (D.z*V.z);
double tmp4 = (2 * tmp5);
double tmp3 = (tmp6 - tmp4);
double tmp1 = (tmp3 + tmp2);
double tmp25 = (tmp1*tmp26);
double tmp24 = (4 * tmp25);
double tmp23 = (tmp111 - tmp24);
if (tmp23 < 0.0)
//Determinant is less than 0 (No solutions)
return IntersectionList();
double tmp22 = sqrt(tmp23);
double tmp178 = (tmp180 - tmp179);
double tmp177 = (tmp178 - tmp149);
double tmp175 = (tmp177 + tmp176);
double tmp173 = (tmp175 + tmp174);
double tmp172 = (tmp173 + tmp148);
double tmp170 = (tmp172 - tmp171);
double tmp169 = (tmp170 + tmp146);
double tmp167 = (tmp169 + tmp168);
double tmp166 = (tmp167 - tmp91);
double tmp165 = (tmp166 + tmp143);
double tmp164 = (tmp165 - tmp85);
double tmp162 = (tmp164 - tmp163);
double tmp161 = (tmp162 + tmp133);
double tmp159 = (tmp161 + tmp160);
double tmp158 = (tmp159 - tmp69);
double tmp157 = (tmp158 + tmp130);
double tmp156 = (tmp157 - tmp63);
double tmp155 = (tmp156 - tmp121);
double tmp154 = (tmp155 + tmp50);
double tmp153 = (tmp154 + tmp118);
double tmp152 = (tmp153 - tmp39);
double tmp151 = (tmp152 + tmp115);
double tmp150 = (tmp151 - tmp32);
double tmp21 = (tmp22 / 2.);
r2 = ((tmp150 + tmp21) / tmp1);
r1 = ((tmp150 - tmp21) / tmp1);
}
#undef D
#undef O
#undef S
#undef V
IntersectionList lst;
Intersection isect;
isect.SurfaceVel = Vector3d::zero();
isect.RefFrame = RefFrame;
isect.Object = ObjectRef(this);
isect.Colour = ColourSource;
isect.IncomingDir = ray.Direction;
{
isect.Position = ray.Origin + ray.GetFourVelocity() * r1;
Vector3d PosAtTime = subvec<3>(InitialPosition) + RefFrame.Velocity * (InitialPosition.t - isect.Position.t);
isect.Normal = normalize(subvec<3>(isect.Position) - PosAtTime);
lst.push_back(isect);
}
{
isect.Position = ray.Origin + ray.GetFourVelocity() * r2;
Vector3d PosAtTime = subvec<3>(InitialPosition) + RefFrame.Velocity * (InitialPosition.t - isect.Position.t);
isect.Normal = normalize(subvec<3>(isect.Position) - PosAtTime);
lst.push_back(isect);
}
return lst;
}
