381 lines
10 KiB
C++
381 lines
10 KiB
C++
/**
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@file Ray.h
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Ray class
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@maintainer Morgan McGuire, http://graphics.cs.williams.edu
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@created 2002-07-12
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@edited 2009-06-29
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*/
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#ifndef G3D_Ray_h
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#define G3D_Ray_h
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#include "G3D/platform.h"
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#include "G3D/Vector3.h"
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#include "G3D/Triangle.h"
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namespace G3D {
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/**
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A 3D Ray.
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*/
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class Ray {
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private:
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friend class Intersect;
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Point3 m_origin;
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/** Unit length */
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Vector3 m_direction;
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/** 1.0 / direction */
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Vector3 m_invDirection;
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/** The following are for the "ray slope" optimization from
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"Fast Ray / Axis-Aligned Bounding Box Overlap Tests using Ray Slopes"
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by Martin Eisemann, Thorsten Grosch, Stefan M<>üller and Marcus Magnor
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Computer Graphics Lab, TU Braunschweig, Germany and
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University of Koblenz-Landau, Germany */
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enum Classification {MMM, MMP, MPM, MPP, PMM, PMP, PPM, PPP, POO, MOO, OPO, OMO, OOP, OOM, OMM, OMP, OPM, OPP, MOM, MOP, POM, POP, MMO, MPO, PMO, PPO};
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Classification classification;
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/** ray slope */
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float ibyj, jbyi, kbyj, jbyk, ibyk, kbyi;
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/** Precomputed components */
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float c_xy, c_xz, c_yx, c_yz, c_zx, c_zy;
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public:
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/** \param direction Assumed to have unit length */
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void set(const Point3& origin, const Vector3& direction);
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const Point3& origin() const {
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return m_origin;
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}
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/** Unit direction vector. */
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const Vector3& direction() const {
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return m_direction;
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}
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/** Component-wise inverse of direction vector. May have inf() components */
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const Vector3& invDirection() const {
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return m_invDirection;
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}
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Ray() {
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set(Point3::zero(), Vector3::unitX());
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}
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/** \param direction Assumed to have unit length */
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Ray(const Point3& origin, const Vector3& direction) {
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set(origin, direction);
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}
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Ray(class BinaryInput& b);
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void serialize(class BinaryOutput& b) const;
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void deserialize(class BinaryInput& b);
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/**
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Creates a Ray from a origin and a (nonzero) unit direction.
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*/
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static Ray fromOriginAndDirection(const Point3& point, const Vector3& direction) {
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return Ray(point, direction);
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}
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/** Returns a new ray which has the same direction but an origin
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advanced along direction by @a distance */
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Ray bumpedRay(float distance) const {
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return Ray(m_origin + m_direction * distance, m_direction);
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}
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/** Returns a new ray which has the same direction but an origin
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advanced by \a distance * \a bumpDirection */
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Ray bumpedRay(float distance, const Vector3& bumpDirection) const {
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return Ray(m_origin + bumpDirection * distance, m_direction);
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}
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/**
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\brief Returns the closest point on the Ray to point.
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*/
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Point3 closestPoint(const Point3& point) const {
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float t = m_direction.dot(point - m_origin);
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if (t < 0) {
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return m_origin;
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} else {
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return m_origin + m_direction * t;
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}
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}
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/**
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Returns the closest distance between point and the Ray
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*/
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float distance(const Point3& point) const {
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return (closestPoint(point) - point).magnitude();
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}
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/**
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Returns the point where the Ray and plane intersect. If there
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is no intersection, returns a point at infinity.
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Planes are considered one-sided, so the ray will not intersect
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a plane where the normal faces in the traveling direction.
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*/
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Point3 intersection(const class Plane& plane) const;
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/**
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Returns the distance until intersection with the sphere or the (solid) ball bounded by the sphere.
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Will be 0 if inside the sphere, inf if there is no intersection.
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The ray direction is <B>not</B> normalized. If the ray direction
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has unit length, the distance from the origin to intersection
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is equal to the time. If the direction does not have unit length,
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the distance = time * direction.length().
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See also the G3D::CollisionDetection "movingPoint" methods,
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which give more information about the intersection.
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\param solid If true, rays inside the sphere immediately intersect (good for collision detection). If false, they hit the opposite side of the sphere (good for ray tracing).
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*/
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float intersectionTime(const class Sphere& sphere, bool solid = false) const;
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float intersectionTime(const class Plane& plane) const;
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float intersectionTime(const class Box& box) const;
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float intersectionTime(const class AABox& box) const;
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/**
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The three extra arguments are the weights of vertices 0, 1, and 2
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at the intersection point; they are useful for texture mapping
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and interpolated normals.
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*/
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float intersectionTime(
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const Vector3& v0, const Vector3& v1, const Vector3& v2,
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const Vector3& edge01, const Vector3& edge02,
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float& w0, float& w1, float& w2) const;
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/**
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Ray-triangle intersection for a 1-sided triangle. Fastest version.
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@cite http://www.acm.org/jgt/papers/MollerTrumbore97/
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http://www.graphics.cornell.edu/pubs/1997/MT97.html
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*/
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float intersectionTime(
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const Point3& vert0,
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const Point3& vert1,
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const Point3& vert2,
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const Vector3& edge01,
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const Vector3& edge02) const;
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float intersectionTime(
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const Point3& vert0,
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const Point3& vert1,
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const Point3& vert2) const {
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return intersectionTime(vert0, vert1, vert2, vert1 - vert0, vert2 - vert0);
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}
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float intersectionTime(
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const Point3& vert0,
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const Point3& vert1,
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const Point3& vert2,
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float& w0,
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float& w1,
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float& w2) const {
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return intersectionTime(vert0, vert1, vert2, vert1 - vert0, vert2 - vert0, w0, w1, w2);
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}
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/* One-sided triangle
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*/
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float intersectionTime(const Triangle& triangle) const {
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return intersectionTime(
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triangle.vertex(0), triangle.vertex(1), triangle.vertex(2),
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triangle.edge01(), triangle.edge02());
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}
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float intersectionTime
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(const Triangle& triangle,
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float& w0,
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float& w1,
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float& w2) const {
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return intersectionTime(triangle.vertex(0), triangle.vertex(1), triangle.vertex(2),
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triangle.edge01(), triangle.edge02(), w0, w1, w2);
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}
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/** Refracts about the normal
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using G3D::Vector3::refractionDirection
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and bumps the ray slightly from the newOrigin. */
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Ray refract(
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const Vector3& newOrigin,
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const Vector3& normal,
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float iInside,
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float iOutside) const;
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/** Reflects about the normal
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using G3D::Vector3::reflectionDirection
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and bumps the ray slightly from
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the newOrigin. */
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Ray reflect(
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const Vector3& newOrigin,
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const Vector3& normal) const;
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};
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#define EPSILON 0.000001
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#define CROSS(dest,v1,v2) \
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dest[0]=v1[1]*v2[2]-v1[2]*v2[1]; \
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dest[1]=v1[2]*v2[0]-v1[0]*v2[2]; \
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dest[2]=v1[0]*v2[1]-v1[1]*v2[0];
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#define DOT(v1,v2) (v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2])
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#define SUB(dest,v1,v2) \
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dest[0]=v1[0]-v2[0]; \
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dest[1]=v1[1]-v2[1]; \
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dest[2]=v1[2]-v2[2];
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inline float Ray::intersectionTime(
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const Point3& vert0,
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const Point3& vert1,
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const Point3& vert2,
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const Vector3& edge1,
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const Vector3& edge2) const {
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(void)vert1;
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(void)vert2;
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// Barycenteric coords
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float u, v;
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float tvec[3], pvec[3], qvec[3];
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// begin calculating determinant - also used to calculate U parameter
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CROSS(pvec, m_direction, edge2);
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// if determinant is near zero, ray lies in plane of triangle
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const float det = DOT(edge1, pvec);
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if (det < EPSILON) {
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return finf();
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}
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// calculate distance from vert0 to ray origin
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SUB(tvec, m_origin, vert0);
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// calculate U parameter and test bounds
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u = DOT(tvec, pvec);
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if ((u < 0.0f) || (u > det)) {
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// Hit the plane outside the triangle
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return finf();
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}
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// prepare to test V parameter
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CROSS(qvec, tvec, edge1);
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// calculate V parameter and test bounds
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v = DOT(m_direction, qvec);
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if ((v < 0.0f) || (u + v > det)) {
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// Hit the plane outside the triangle
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return finf();
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}
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// Case where we don't need correct (u, v):
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const float t = DOT(edge2, qvec);
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if (t >= 0.0f) {
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// Note that det must be positive
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return t / det;
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} else {
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// We had to travel backwards in time to intersect
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return finf();
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}
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}
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inline float Ray::intersectionTime
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(const Point3& vert0,
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const Point3& vert1,
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const Point3& vert2,
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const Vector3& edge1,
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const Vector3& edge2,
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float& w0,
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float& w1,
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float& w2) const {
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(void)vert1;
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(void)vert2;
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// Barycenteric coords
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float u, v;
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float tvec[3], pvec[3], qvec[3];
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// begin calculating determinant - also used to calculate U parameter
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CROSS(pvec, m_direction, edge2);
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// if determinant is near zero, ray lies in plane of triangle
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const float det = DOT(edge1, pvec);
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if (det < EPSILON) {
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return finf();
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}
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// calculate distance from vert0 to ray origin
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SUB(tvec, m_origin, vert0);
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// calculate U parameter and test bounds
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u = DOT(tvec, pvec);
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if ((u < 0.0f) || (u > det)) {
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// Hit the plane outside the triangle
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return finf();
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}
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// prepare to test V parameter
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CROSS(qvec, tvec, edge1);
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// calculate V parameter and test bounds
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v = DOT(m_direction, qvec);
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if ((v < 0.0f) || (u + v > det)) {
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// Hit the plane outside the triangle
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return finf();
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}
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float t = DOT(edge2, qvec);
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if (t >= 0) {
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const float inv_det = 1.0f / det;
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t *= inv_det;
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u *= inv_det;
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v *= inv_det;
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w0 = (1.0f - u - v);
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w1 = u;
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w2 = v;
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return t;
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} else {
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// We had to travel backwards in time to intersect
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return finf();
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}
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}
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#undef EPSILON
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#undef CROSS
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#undef DOT
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#undef SUB
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}// namespace
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#endif
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