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// Copyright 2009-2020 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include "triangle.h"
#include "trianglev.h"
#include "trianglev_mb.h"
#include "intersector_epilog.h"
/*! Modified Pluecker ray/triangle intersector. The test first shifts
* the ray origin into the origin of the coordinate system and then
* uses Pluecker coordinates for the intersection. Due to the shift,
* the Pluecker coordinate calculation simplifies and the tests get
* numerically stable. The edge equations are watertight along the
* edge for neighboring triangles. */
namespace embree
{
namespace isa
{
template<int M, typename UVMapper>
struct PlueckerHitM
{
__forceinline PlueckerHitM(const vfloat<M>& U, const vfloat<M>& V, const vfloat<M>& UVW, const vfloat<M>& t, const Vec3vf<M>& Ng, const UVMapper& mapUV)
: U(U), V(V), UVW(UVW), mapUV(mapUV), vt(t), vNg(Ng) {}
__forceinline void finalize()
{
const vbool<M> invalid = abs(UVW) < min_rcp_input;
const vfloat<M> rcpUVW = select(invalid,vfloat<M>(0.0f),rcp(UVW));
vu = U * rcpUVW;
vv = V * rcpUVW;
mapUV(vu,vv);
}
__forceinline Vec2f uv (const size_t i) const { return Vec2f(vu[i],vv[i]); }
__forceinline float t (const size_t i) const { return vt[i]; }
__forceinline Vec3fa Ng(const size_t i) const { return Vec3fa(vNg.x[i],vNg.y[i],vNg.z[i]); }
private:
const vfloat<M> U;
const vfloat<M> V;
const vfloat<M> UVW;
const UVMapper& mapUV;
public:
vfloat<M> vu;
vfloat<M> vv;
vfloat<M> vt;
Vec3vf<M> vNg;
};
template<int M>
struct PlueckerIntersector1
{
__forceinline PlueckerIntersector1() {}
__forceinline PlueckerIntersector1(const Ray& ray, const void* ptr) {}
template<typename UVMapper, typename Epilog>
__forceinline bool intersect(Ray& ray,
const Vec3vf<M>& tri_v0,
const Vec3vf<M>& tri_v1,
const Vec3vf<M>& tri_v2,
const UVMapper& mapUV,
const Epilog& epilog) const
{
/* calculate vertices relative to ray origin */
const Vec3vf<M> O = Vec3vf<M>((Vec3fa)ray.org);
const Vec3vf<M> D = Vec3vf<M>((Vec3fa)ray.dir);
const Vec3vf<M> v0 = tri_v0-O;
const Vec3vf<M> v1 = tri_v1-O;
const Vec3vf<M> v2 = tri_v2-O;
/* calculate triangle edges */
const Vec3vf<M> e0 = v2-v0;
const Vec3vf<M> e1 = v0-v1;
const Vec3vf<M> e2 = v1-v2;
/* perform edge tests */
const vfloat<M> U = dot(cross(e0,v2+v0),D);
const vfloat<M> V = dot(cross(e1,v0+v1),D);
const vfloat<M> W = dot(cross(e2,v1+v2),D);
const vfloat<M> UVW = U+V+W;
const vfloat<M> eps = float(ulp)*abs(UVW);
#if defined(EMBREE_BACKFACE_CULLING)
vbool<M> valid = max(U,V,W) <= eps;
#else
vbool<M> valid = (min(U,V,W) >= -eps) | (max(U,V,W) <= eps);
#endif
if (unlikely(none(valid))) return false;
/* calculate geometry normal and denominator */
const Vec3vf<M> Ng = stable_triangle_normal(e0,e1,e2);
const vfloat<M> den = twice(dot(Ng,D));
/* perform depth test */
const vfloat<M> T = twice(dot(v0,Ng));
const vfloat<M> t = rcp(den)*T;
valid &= vfloat<M>(ray.tnear()) <= t & t <= vfloat<M>(ray.tfar);
valid &= den != vfloat<M>(zero);
if (unlikely(none(valid))) return false;
/* update hit information */
PlueckerHitM<M,UVMapper> hit(U,V,UVW,t,Ng,mapUV);
return epilog(valid,hit);
}
};
template<int K, typename UVMapper>
struct PlueckerHitK
{
__forceinline PlueckerHitK(const vfloat<K>& U, const vfloat<K>& V, const vfloat<K>& UVW, const vfloat<K>& t, const Vec3vf<K>& Ng, const UVMapper& mapUV)
: U(U), V(V), UVW(UVW), t(t), Ng(Ng), mapUV(mapUV) {}
__forceinline std::tuple<vfloat<K>,vfloat<K>,vfloat<K>,Vec3vf<K>> operator() () const
{
const vbool<K> invalid = abs(UVW) < min_rcp_input;
const vfloat<K> rcpUVW = select(invalid,vfloat<K>(0.0f),rcp(UVW));
vfloat<K> u = U * rcpUVW;
vfloat<K> v = V * rcpUVW;
mapUV(u,v);
return std::make_tuple(u,v,t,Ng);
}
private:
const vfloat<K> U;
const vfloat<K> V;
const vfloat<K> UVW;
const vfloat<K> t;
const Vec3vf<K> Ng;
const UVMapper& mapUV;
};
template<int M, int K>
struct PlueckerIntersectorK
{
__forceinline PlueckerIntersectorK(const vbool<K>& valid, const RayK<K>& ray) {}
/*! Intersects K rays with one of M triangles. */
template<typename UVMapper, typename Epilog>
__forceinline vbool<K> intersectK(const vbool<K>& valid0,
RayK<K>& ray,
const Vec3vf<K>& tri_v0,
const Vec3vf<K>& tri_v1,
const Vec3vf<K>& tri_v2,
const UVMapper& mapUV,
const Epilog& epilog) const
{
/* calculate vertices relative to ray origin */
vbool<K> valid = valid0;
const Vec3vf<K> O = ray.org;
const Vec3vf<K> D = ray.dir;
const Vec3vf<K> v0 = tri_v0-O;
const Vec3vf<K> v1 = tri_v1-O;
const Vec3vf<K> v2 = tri_v2-O;
/* calculate triangle edges */
const Vec3vf<K> e0 = v2-v0;
const Vec3vf<K> e1 = v0-v1;
const Vec3vf<K> e2 = v1-v2;
/* perform edge tests */
const vfloat<K> U = dot(Vec3vf<K>(cross(e0,v2+v0)),D);
const vfloat<K> V = dot(Vec3vf<K>(cross(e1,v0+v1)),D);
const vfloat<K> W = dot(Vec3vf<K>(cross(e2,v1+v2)),D);
const vfloat<K> UVW = U+V+W;
const vfloat<K> eps = float(ulp)*abs(UVW);
#if defined(EMBREE_BACKFACE_CULLING)
valid &= max(U,V,W) <= eps;
#else
valid &= (min(U,V,W) >= -eps) | (max(U,V,W) <= eps);
#endif
if (unlikely(none(valid))) return false;
/* calculate geometry normal and denominator */
const Vec3vf<K> Ng = stable_triangle_normal(e0,e1,e2);
const vfloat<K> den = twice(dot(Vec3vf<K>(Ng),D));
/* perform depth test */
const vfloat<K> T = twice(dot(v0,Vec3vf<K>(Ng)));
const vfloat<K> t = rcp(den)*T;
valid &= ray.tnear() <= t & t <= ray.tfar;
valid &= den != vfloat<K>(zero);
if (unlikely(none(valid))) return false;
/* calculate hit information */
PlueckerHitK<K,UVMapper> hit(U,V,UVW,t,Ng,mapUV);
return epilog(valid,hit);
}
/*! Intersect k'th ray from ray packet of size K with M triangles. */
template<typename UVMapper, typename Epilog>
__forceinline bool intersect(RayK<K>& ray, size_t k,
const Vec3vf<M>& tri_v0,
const Vec3vf<M>& tri_v1,
const Vec3vf<M>& tri_v2,
const UVMapper& mapUV,
const Epilog& epilog) const
{
/* calculate vertices relative to ray origin */
const Vec3vf<M> O = broadcast<vfloat<M>>(ray.org,k);
const Vec3vf<M> D = broadcast<vfloat<M>>(ray.dir,k);
const Vec3vf<M> v0 = tri_v0-O;
const Vec3vf<M> v1 = tri_v1-O;
const Vec3vf<M> v2 = tri_v2-O;
/* calculate triangle edges */
const Vec3vf<M> e0 = v2-v0;
const Vec3vf<M> e1 = v0-v1;
const Vec3vf<M> e2 = v1-v2;
/* perform edge tests */
const vfloat<M> U = dot(cross(e0,v2+v0),D);
const vfloat<M> V = dot(cross(e1,v0+v1),D);
const vfloat<M> W = dot(cross(e2,v1+v2),D);
const vfloat<M> UVW = U+V+W;
const vfloat<M> eps = float(ulp)*abs(UVW);
#if defined(EMBREE_BACKFACE_CULLING)
vbool<M> valid = max(U,V,W) <= eps;
#else
vbool<M> valid = (min(U,V,W) >= -eps) | (max(U,V,W) <= eps);
#endif
if (unlikely(none(valid))) return false;
/* calculate geometry normal and denominator */
const Vec3vf<M> Ng = stable_triangle_normal(e0,e1,e2);
const vfloat<M> den = twice(dot(Ng,D));
/* perform depth test */
const vfloat<M> T = twice(dot(v0,Ng));
const vfloat<M> t = rcp(den)*T;
valid &= vfloat<M>(ray.tnear()[k]) <= t & t <= vfloat<M>(ray.tfar[k]);
if (unlikely(none(valid))) return false;
/* avoid division by 0 */
valid &= den != vfloat<M>(zero);
if (unlikely(none(valid))) return false;
/* update hit information */
PlueckerHitM<M,UVMapper> hit(U,V,UVW,t,Ng,mapUV);
return epilog(valid,hit);
}
};
}
}
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