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++ // Copyright 2009-2021 Intel Corporation
++ // SPDX-License-Identifier: Apache-2.0
++
++ #pragma once
++
++ #include "../common/ray.h"
++ #include "quad_intersector.h"
++ #include "curve_intersector_precalculations.h"
++
++ #define Bezier1Intersector1 RibbonCurve1Intersector1
++ #define Bezier1IntersectorK RibbonCurve1IntersectorK
++
++ namespace embree
++ {
++ namespace isa
++ {
++ template<typename NativeCurve3ff, int M>
++ struct RibbonHit
++ {
++ __forceinline RibbonHit() {}
++
++ __forceinline RibbonHit(const vbool<M>& valid, const vfloat<M>& U, const vfloat<M>& V, const vfloat<M>& T, const int i, const int N,
++ const NativeCurve3ff& curve3D)
++ : U(U), V(V), T(T), i(i), N(N), curve3D(curve3D), valid(valid) {}
++
++ __forceinline void finalize()
++ {
++ vu = (vfloat<M>(step)+U+vfloat<M>(float(i)))*(1.0f/float(N));
++ vv = V;
++ vt = T;
++ }
++
++ __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 curve3D.eval_du(vu[i]); }
++
++ __forceinline Vec2vf<M> uv() const { return Vec2vf<M>(vu,vv); }
++ __forceinline vfloat<M> t () const { return vt; }
++ __forceinline Vec3vf<M> Ng() const { return (Vec3vf<M>) curve3D.template veval_du<M>(vu); }
++
++ public:
++ vfloat<M> U;
++ vfloat<M> V;
++ vfloat<M> T;
++ int i, N;
++ NativeCurve3ff curve3D;
++
++ public:
++ vbool<M> valid;
++ vfloat<M> vu;
++ vfloat<M> vv;
++ vfloat<M> vt;
++ };
++
++ /* calculate squared distance of point p0 to line p1->p2 */
++ __forceinline std::pair<vfloatx,vfloatx> sqr_point_line_distance(const Vec2vfx& p0, const Vec2vfx& p1, const Vec2vfx& p2)
++ {
++ const vfloatx num = det(p2-p1,p1-p0);
++ const vfloatx den2 = dot(p2-p1,p2-p1);
++ return std::make_pair(num*num,den2);
++ }
++
++ /* performs culling against a cylinder */
++ __forceinline vboolx cylinder_culling_test(const Vec2vfx& p0, const Vec2vfx& p1, const Vec2vfx& p2, const vfloatx& r)
++ {
++ const std::pair<vfloatx,vfloatx> d = sqr_point_line_distance(p0,p1,p2);
++ return d.first <= r*r*d.second;
++ }
++
++ template<typename NativeCurve3ff, typename Epilog>
++ __forceinline bool intersect_ribbon(const Vec3fa& ray_org, const Vec3fa& ray_dir, const float ray_tnear, const float& ray_tfar,
++ const LinearSpace3fa& ray_space, const float& depth_scale,
++ const NativeCurve3ff& curve3D, const int N,
++ const Epilog& epilog)
++ {
++ /* transform control points into ray space */
++ const NativeCurve3ff curve2D = curve3D.xfm_pr(ray_space,ray_org);
++ float eps = 4.0f*float(ulp)*reduce_max(max(abs(curve2D.v0),abs(curve2D.v1),abs(curve2D.v2),abs(curve2D.v3)));
++
++ /* evaluate the bezier curve */
++ bool ishit = false;
++ vboolx valid = vfloatx(step) < vfloatx(float(N));
++ const Vec4vfx p0 = curve2D.template eval0<VSIZEX>(0,N);
++ const Vec4vfx p1 = curve2D.template eval1<VSIZEX>(0,N);
++ valid &= cylinder_culling_test(zero,Vec2vfx(p0.x,p0.y),Vec2vfx(p1.x,p1.y),max(p0.w,p1.w));
++
++ if (any(valid))
++ {
++ Vec3vfx dp0dt = curve2D.template derivative0<VSIZEX>(0,N);
++ Vec3vfx dp1dt = curve2D.template derivative1<VSIZEX>(0,N);
++ dp0dt = select(reduce_max(abs(dp0dt)) < vfloatx(eps),Vec3vfx(p1-p0),dp0dt);
++ dp1dt = select(reduce_max(abs(dp1dt)) < vfloatx(eps),Vec3vfx(p1-p0),dp1dt);
++ const Vec3vfx n0(dp0dt.y,-dp0dt.x,0.0f);
++ const Vec3vfx n1(dp1dt.y,-dp1dt.x,0.0f);
++ const Vec3vfx nn0 = normalize(n0);
++ const Vec3vfx nn1 = normalize(n1);
++ const Vec3vfx lp0 = madd(p0.w,nn0,Vec3vfx(p0));
++ const Vec3vfx lp1 = madd(p1.w,nn1,Vec3vfx(p1));
++ const Vec3vfx up0 = nmadd(p0.w,nn0,Vec3vfx(p0));
++ const Vec3vfx up1 = nmadd(p1.w,nn1,Vec3vfx(p1));
++
++ vfloatx vu,vv,vt;
++ vboolx valid0 = intersect_quad_backface_culling<VSIZEX>(valid,zero,Vec3fa(0,0,1),ray_tnear,ray_tfar,lp0,lp1,up1,up0,vu,vv,vt);
++
++ if (any(valid0))
++ {
++ /* ignore self intersections */
++ if (EMBREE_CURVE_SELF_INTERSECTION_AVOIDANCE_FACTOR != 0.0f) {
++ vfloatx r = lerp(p0.w, p1.w, vu);
++ valid0 &= vt > float(EMBREE_CURVE_SELF_INTERSECTION_AVOIDANCE_FACTOR)*r*depth_scale;
++ }
++
++ if (any(valid0))
++ {
++ vv = madd(2.0f,vv,vfloatx(-1.0f));
++ RibbonHit<NativeCurve3ff,VSIZEX> bhit(valid0,vu,vv,vt,0,N,curve3D);
++ ishit |= epilog(bhit.valid,bhit);
++ }
++ }
++ }
++
++ if (unlikely(VSIZEX < N))
++ {
++ /* process SIMD-size many segments per iteration */
++ for (int i=VSIZEX; i<N; i+=VSIZEX)
++ {
++ /* evaluate the bezier curve */
++ vboolx valid = vintx(i)+vintx(step) < vintx(N);
++ const Vec4vfx p0 = curve2D.template eval0<VSIZEX>(i,N);
++ const Vec4vfx p1 = curve2D.template eval1<VSIZEX>(i,N);
++ valid &= cylinder_culling_test(zero,Vec2vfx(p0.x,p0.y),Vec2vfx(p1.x,p1.y),max(p0.w,p1.w));
++ if (none(valid)) continue;
++
++ Vec3vfx dp0dt = curve2D.template derivative0<VSIZEX>(i,N);
++ Vec3vfx dp1dt = curve2D.template derivative1<VSIZEX>(i,N);
++ dp0dt = select(reduce_max(abs(dp0dt)) < vfloatx(eps),Vec3vfx(p1-p0),dp0dt);
++ dp1dt = select(reduce_max(abs(dp1dt)) < vfloatx(eps),Vec3vfx(p1-p0),dp1dt);
++ const Vec3vfx n0(dp0dt.y,-dp0dt.x,0.0f);
++ const Vec3vfx n1(dp1dt.y,-dp1dt.x,0.0f);
++ const Vec3vfx nn0 = normalize(n0);
++ const Vec3vfx nn1 = normalize(n1);
++ const Vec3vfx lp0 = madd(p0.w,nn0,Vec3vfx(p0));
++ const Vec3vfx lp1 = madd(p1.w,nn1,Vec3vfx(p1));
++ const Vec3vfx up0 = nmadd(p0.w,nn0,Vec3vfx(p0));
++ const Vec3vfx up1 = nmadd(p1.w,nn1,Vec3vfx(p1));
++
++ vfloatx vu,vv,vt;
++ vboolx valid0 = intersect_quad_backface_culling<VSIZEX>(valid,zero,Vec3fa(0,0,1),ray_tnear,ray_tfar,lp0,lp1,up1,up0,vu,vv,vt);
++
++ if (any(valid0))
++ {
++ /* ignore self intersections */
++ if (EMBREE_CURVE_SELF_INTERSECTION_AVOIDANCE_FACTOR != 0.0f) {
++ vfloatx r = lerp(p0.w, p1.w, vu);
++ valid0 &= vt > float(EMBREE_CURVE_SELF_INTERSECTION_AVOIDANCE_FACTOR)*r*depth_scale;
++ }
++
++ if (any(valid0))
++ {
++ vv = madd(2.0f,vv,vfloatx(-1.0f));
++ RibbonHit<NativeCurve3ff,VSIZEX> bhit(valid0,vu,vv,vt,i,N,curve3D);
++ ishit |= epilog(bhit.valid,bhit);
++ }
++ }
++ }
++ }
++ return ishit;
++ }
++
++ template<template<typename Ty> class NativeCurve>
++ struct RibbonCurve1Intersector1
++ {
++ typedef NativeCurve<Vec3ff> NativeCurve3ff;
++
++ template<typename Epilog>
++ __forceinline bool intersect(const CurvePrecalculations1& pre, Ray& ray,
++ IntersectContext* context,
++ const CurveGeometry* geom, const unsigned int primID,
++ const Vec3ff& v0, const Vec3ff& v1, const Vec3ff& v2, const Vec3ff& v3,
++ const Epilog& epilog)
++ {
++ const int N = geom->tessellationRate;
++ NativeCurve3ff curve(v0,v1,v2,v3);
++ curve = enlargeRadiusToMinWidth(context,geom,ray.org,curve);
++ return intersect_ribbon<NativeCurve3ff>(ray.org,ray.dir,ray.tnear(),ray.tfar,
++ pre.ray_space,pre.depth_scale,
++ curve,N,
++ epilog);
++ }
++ };
++
++ template<template<typename Ty> class NativeCurve, int K>
++ struct RibbonCurve1IntersectorK
++ {
++ typedef NativeCurve<Vec3ff> NativeCurve3ff;
++
++ template<typename Epilog>
++ __forceinline bool intersect(const CurvePrecalculationsK<K>& pre, RayK<K>& ray, size_t k,
++ IntersectContext* context,
++ const CurveGeometry* geom, const unsigned int primID,
++ const Vec3ff& v0, const Vec3ff& v1, const Vec3ff& v2, const Vec3ff& v3,
++ const Epilog& epilog)
++ {
++ const int N = geom->tessellationRate;
++ const Vec3fa ray_org(ray.org.x[k],ray.org.y[k],ray.org.z[k]);
++ const Vec3fa ray_dir(ray.dir.x[k],ray.dir.y[k],ray.dir.z[k]);
++ NativeCurve3ff curve(v0,v1,v2,v3);
++ curve = enlargeRadiusToMinWidth(context,geom,ray_org,curve);
++ return intersect_ribbon<NativeCurve3ff>(ray_org,ray_dir,ray.tnear()[k],ray.tfar[k],
++ pre.ray_space[k],pre.depth_scale[k],
++ curve,N,
++ epilog);
++ }
++ };
++ }
++ }