364 lines
15 KiB
C++
364 lines
15 KiB
C++
// Copyright 2009-2021 Intel Corporation
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include "../common/ray.h"
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#include "cylinder.h"
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#include "plane.h"
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#include "line_intersector.h"
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#include "curve_intersector_precalculations.h"
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namespace embree
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{
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namespace isa
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{
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static const size_t numJacobianIterations = 5;
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#if defined(__AVX__)
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static const size_t numBezierSubdivisions = 2;
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#else
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static const size_t numBezierSubdivisions = 3;
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#endif
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struct BezierCurveHit
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{
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__forceinline BezierCurveHit() {}
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__forceinline BezierCurveHit(const float t, const float u, const Vec3fa& Ng)
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: t(t), u(u), v(0.0f), Ng(Ng) {}
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__forceinline BezierCurveHit(const float t, const float u, const float v, const Vec3fa& Ng)
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: t(t), u(u), v(v), Ng(Ng) {}
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__forceinline void finalize() {}
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public:
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float t;
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float u;
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float v;
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Vec3fa Ng;
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};
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template<typename NativeCurve3ff, typename Ray, typename Epilog>
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__forceinline bool intersect_bezier_iterative_debug(const Ray& ray, const float dt, const NativeCurve3ff& curve, size_t i,
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const vfloatx& u, const BBox<vfloatx>& tp, const BBox<vfloatx>& h0, const BBox<vfloatx>& h1,
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const Vec3vfx& Ng, const Vec4vfx& dP0du, const Vec4vfx& dP3du,
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const Epilog& epilog)
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{
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if (tp.lower[i]+dt > ray.tfar) return false;
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Vec3fa Ng_o = Vec3fa(Ng.x[i],Ng.y[i],Ng.z[i]);
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if (h0.lower[i] == tp.lower[i]) Ng_o = -Vec3fa(dP0du.x[i],dP0du.y[i],dP0du.z[i]);
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if (h1.lower[i] == tp.lower[i]) Ng_o = +Vec3fa(dP3du.x[i],dP3du.y[i],dP3du.z[i]);
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BezierCurveHit hit(tp.lower[i]+dt,u[i],Ng_o);
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return epilog(hit);
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}
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template<typename NativeCurve3ff, typename Ray, typename Epilog>
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__forceinline bool intersect_bezier_iterative_jacobian(const Ray& ray, const float dt, const NativeCurve3ff& curve, float u, float t, const Epilog& epilog)
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{
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const Vec3fa org = zero;
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const Vec3fa dir = ray.dir;
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const float length_ray_dir = length(dir);
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/* error of curve evaluations is proportional to largest coordinate */
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const BBox3ff box = curve.bounds();
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const float P_err = 16.0f*float(ulp)*reduce_max(max(abs(box.lower),abs(box.upper)));
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for (size_t i=0; i<numJacobianIterations; i++)
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{
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const Vec3fa Q = madd(Vec3fa(t),dir,org);
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//const Vec3fa dQdu = zero;
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const Vec3fa dQdt = dir;
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const float Q_err = 16.0f*float(ulp)*length_ray_dir*t; // works as org=zero here
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Vec3ff P,dPdu,ddPdu; curve.eval(u,P,dPdu,ddPdu);
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//const Vec3fa dPdt = zero;
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const Vec3fa R = Q-P;
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const float len_R = length(R); //reduce_max(abs(R));
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const float R_err = max(Q_err,P_err);
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const Vec3fa dRdu = /*dQdu*/-dPdu;
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const Vec3fa dRdt = dQdt;//-dPdt;
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const Vec3fa T = normalize(dPdu);
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const Vec3fa dTdu = dnormalize(dPdu,ddPdu);
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//const Vec3fa dTdt = zero;
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const float cos_err = P_err/length(dPdu);
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/* Error estimate for dot(R,T):
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dot(R,T) = cos(R,T) |R| |T|
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= (cos(R,T) +- cos_error) * (|R| +- |R|_err) * (|T| +- |T|_err)
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= cos(R,T)*|R|*|T|
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+- cos(R,T)*(|R|*|T|_err + |T|*|R|_err)
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+- cos_error*(|R| + |T|)
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+- lower order terms
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with cos(R,T) being in [0,1] and |T| = 1 we get:
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dot(R,T)_err = |R|*|T|_err + |R|_err = cos_error*(|R|+1)
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*/
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const float f = dot(R,T);
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const float f_err = len_R*P_err + R_err + cos_err*(1.0f+len_R);
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const float dfdu = dot(dRdu,T) + dot(R,dTdu);
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const float dfdt = dot(dRdt,T);// + dot(R,dTdt);
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const float K = dot(R,R)-sqr(f);
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const float dKdu = /*2.0f*/(dot(R,dRdu)-f*dfdu);
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const float dKdt = /*2.0f*/(dot(R,dRdt)-f*dfdt);
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const float rsqrt_K = rsqrt(K);
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const float g = sqrt(K)-P.w;
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const float g_err = R_err + f_err + 16.0f*float(ulp)*box.upper.w;
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const float dgdu = /*0.5f*/dKdu*rsqrt_K-dPdu.w;
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const float dgdt = /*0.5f*/dKdt*rsqrt_K;//-dPdt.w;
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const LinearSpace2f J = LinearSpace2f(dfdu,dfdt,dgdu,dgdt);
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const Vec2f dut = rcp(J)*Vec2f(f,g);
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const Vec2f ut = Vec2f(u,t) - dut;
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u = ut.x; t = ut.y;
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if (abs(f) < f_err && abs(g) < g_err)
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{
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t+=dt;
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if (!(ray.tnear() <= t && t <= ray.tfar)) return false; // rejects NaNs
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if (!(u >= 0.0f && u <= 1.0f)) return false; // rejects NaNs
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const Vec3fa R = normalize(Q-P);
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const Vec3fa U = madd(Vec3fa(dPdu.w),R,dPdu);
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const Vec3fa V = cross(dPdu,R);
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BezierCurveHit hit(t,u,cross(V,U));
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return epilog(hit);
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}
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}
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return false;
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}
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template<typename NativeCurve3ff, typename Ray, typename Epilog>
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bool intersect_bezier_recursive_jacobian(const Ray& ray, const float dt, const NativeCurve3ff& curve,
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float u0, float u1, unsigned int depth, const Epilog& epilog)
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{
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#if defined(__AVX__)
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enum { VSIZEX_ = 8 };
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typedef vbool8 vboolx; // maximally 8-wide to work around KNL issues
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typedef vint8 vintx;
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typedef vfloat8 vfloatx;
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#else
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enum { VSIZEX_ = 4 };
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typedef vbool4 vboolx;
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typedef vint4 vintx;
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typedef vfloat4 vfloatx;
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#endif
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typedef Vec3<vfloatx> Vec3vfx;
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typedef Vec4<vfloatx> Vec4vfx;
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unsigned int maxDepth = numBezierSubdivisions;
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bool found = false;
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const Vec3fa org = zero;
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const Vec3fa dir = ray.dir;
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unsigned int sptr = 0;
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const unsigned int stack_size = numBezierSubdivisions+1; // +1 because of unstable workaround below
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struct StackEntry {
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vboolx valid;
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vfloatx tlower;
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float u0;
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float u1;
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unsigned int depth;
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};
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StackEntry stack[stack_size];
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goto entry;
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/* terminate if stack is empty */
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while (sptr)
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{
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/* pop from stack */
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{
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sptr--;
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vboolx valid = stack[sptr].valid;
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const vfloatx tlower = stack[sptr].tlower;
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valid &= tlower+dt <= ray.tfar;
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if (none(valid)) continue;
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u0 = stack[sptr].u0;
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u1 = stack[sptr].u1;
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depth = stack[sptr].depth;
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const size_t i = select_min(valid,tlower); clear(valid,i);
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stack[sptr].valid = valid;
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if (any(valid)) sptr++; // there are still items on the stack
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/* process next segment */
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const vfloatx vu0 = lerp(u0,u1,vfloatx(step)*(1.0f/(vfloatx::size-1)));
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u0 = vu0[i+0];
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u1 = vu0[i+1];
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}
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entry:
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/* subdivide curve */
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const float dscale = (u1-u0)*(1.0f/(3.0f*(vfloatx::size-1)));
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const vfloatx vu0 = lerp(u0,u1,vfloatx(step)*(1.0f/(vfloatx::size-1)));
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Vec4vfx P0, dP0du; curve.template veval<VSIZEX_>(vu0,P0,dP0du); dP0du = dP0du * Vec4vfx(dscale);
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const Vec4vfx P3 = shift_right_1(P0);
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const Vec4vfx dP3du = shift_right_1(dP0du);
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const Vec4vfx P1 = P0 + dP0du;
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const Vec4vfx P2 = P3 - dP3du;
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/* calculate bounding cylinders */
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const vfloatx rr1 = sqr_point_to_line_distance(Vec3vfx(dP0du),Vec3vfx(P3-P0));
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const vfloatx rr2 = sqr_point_to_line_distance(Vec3vfx(dP3du),Vec3vfx(P3-P0));
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const vfloatx maxr12 = sqrt(max(rr1,rr2));
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const vfloatx one_plus_ulp = 1.0f+2.0f*float(ulp);
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const vfloatx one_minus_ulp = 1.0f-2.0f*float(ulp);
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vfloatx r_outer = max(P0.w,P1.w,P2.w,P3.w)+maxr12;
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vfloatx r_inner = min(P0.w,P1.w,P2.w,P3.w)-maxr12;
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r_outer = one_plus_ulp*r_outer;
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r_inner = max(0.0f,one_minus_ulp*r_inner);
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const CylinderN<vfloatx::size> cylinder_outer(Vec3vfx(P0),Vec3vfx(P3),r_outer);
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const CylinderN<vfloatx::size> cylinder_inner(Vec3vfx(P0),Vec3vfx(P3),r_inner);
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vboolx valid = true; clear(valid,vfloatx::size-1);
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/* intersect with outer cylinder */
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BBox<vfloatx> tc_outer; vfloatx u_outer0; Vec3vfx Ng_outer0; vfloatx u_outer1; Vec3vfx Ng_outer1;
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valid &= cylinder_outer.intersect(org,dir,tc_outer,u_outer0,Ng_outer0,u_outer1,Ng_outer1);
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if (none(valid)) continue;
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/* intersect with cap-planes */
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BBox<vfloatx> tp(ray.tnear()-dt,ray.tfar-dt);
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tp = embree::intersect(tp,tc_outer);
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BBox<vfloatx> h0 = HalfPlaneN<vfloatx::size>(Vec3vfx(P0),+Vec3vfx(dP0du)).intersect(org,dir);
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tp = embree::intersect(tp,h0);
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BBox<vfloatx> h1 = HalfPlaneN<vfloatx::size>(Vec3vfx(P3),-Vec3vfx(dP3du)).intersect(org,dir);
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tp = embree::intersect(tp,h1);
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valid &= tp.lower <= tp.upper;
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if (none(valid)) continue;
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/* clamp and correct u parameter */
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u_outer0 = clamp(u_outer0,vfloatx(0.0f),vfloatx(1.0f));
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u_outer1 = clamp(u_outer1,vfloatx(0.0f),vfloatx(1.0f));
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u_outer0 = lerp(u0,u1,(vfloatx(step)+u_outer0)*(1.0f/float(vfloatx::size)));
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u_outer1 = lerp(u0,u1,(vfloatx(step)+u_outer1)*(1.0f/float(vfloatx::size)));
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/* intersect with inner cylinder */
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BBox<vfloatx> tc_inner;
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vfloatx u_inner0 = zero; Vec3vfx Ng_inner0 = zero; vfloatx u_inner1 = zero; Vec3vfx Ng_inner1 = zero;
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const vboolx valid_inner = cylinder_inner.intersect(org,dir,tc_inner,u_inner0,Ng_inner0,u_inner1,Ng_inner1);
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/* at the unstable area we subdivide deeper */
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const vboolx unstable0 = (!valid_inner) | (abs(dot(Vec3vfx(Vec3fa(ray.dir)),Ng_inner0)) < 0.3f);
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const vboolx unstable1 = (!valid_inner) | (abs(dot(Vec3vfx(Vec3fa(ray.dir)),Ng_inner1)) < 0.3f);
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/* subtract the inner interval from the current hit interval */
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BBox<vfloatx> tp0, tp1;
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subtract(tp,tc_inner,tp0,tp1);
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vboolx valid0 = valid & (tp0.lower <= tp0.upper);
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vboolx valid1 = valid & (tp1.lower <= tp1.upper);
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if (none(valid0 | valid1)) continue;
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/* iterate over all first hits front to back */
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const vintx termDepth0 = select(unstable0,vintx(maxDepth+1),vintx(maxDepth));
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vboolx recursion_valid0 = valid0 & (depth < termDepth0);
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valid0 &= depth >= termDepth0;
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while (any(valid0))
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{
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const size_t i = select_min(valid0,tp0.lower); clear(valid0,i);
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found = found | intersect_bezier_iterative_jacobian(ray,dt,curve,u_outer0[i],tp0.lower[i],epilog);
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//found = found | intersect_bezier_iterative_debug (ray,dt,curve,i,u_outer0,tp0,h0,h1,Ng_outer0,dP0du,dP3du,epilog);
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valid0 &= tp0.lower+dt <= ray.tfar;
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}
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valid1 &= tp1.lower+dt <= ray.tfar;
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/* iterate over all second hits front to back */
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const vintx termDepth1 = select(unstable1,vintx(maxDepth+1),vintx(maxDepth));
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vboolx recursion_valid1 = valid1 & (depth < termDepth1);
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valid1 &= depth >= termDepth1;
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while (any(valid1))
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{
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const size_t i = select_min(valid1,tp1.lower); clear(valid1,i);
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found = found | intersect_bezier_iterative_jacobian(ray,dt,curve,u_outer1[i],tp1.upper[i],epilog);
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//found = found | intersect_bezier_iterative_debug (ray,dt,curve,i,u_outer1,tp1,h0,h1,Ng_outer1,dP0du,dP3du,epilog);
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valid1 &= tp1.lower+dt <= ray.tfar;
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}
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/* push valid segments to stack */
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recursion_valid0 &= tp0.lower+dt <= ray.tfar;
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recursion_valid1 &= tp1.lower+dt <= ray.tfar;
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const vboolx recursion_valid = recursion_valid0 | recursion_valid1;
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if (any(recursion_valid))
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{
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assert(sptr < stack_size);
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stack[sptr].valid = recursion_valid;
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stack[sptr].tlower = select(recursion_valid0,tp0.lower,tp1.lower);
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stack[sptr].u0 = u0;
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stack[sptr].u1 = u1;
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stack[sptr].depth = depth+1;
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sptr++;
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}
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}
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return found;
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}
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template<template<typename Ty> class NativeCurve>
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struct SweepCurve1Intersector1
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{
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typedef NativeCurve<Vec3ff> NativeCurve3ff;
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template<typename Epilog>
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__noinline bool intersect(const CurvePrecalculations1& pre, Ray& ray,
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IntersectContext* context,
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const CurveGeometry* geom, const unsigned int primID,
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const Vec3ff& v0, const Vec3ff& v1, const Vec3ff& v2, const Vec3ff& v3,
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const Epilog& epilog)
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{
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STAT3(normal.trav_prims,1,1,1);
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/* move ray closer to make intersection stable */
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NativeCurve3ff curve0(v0,v1,v2,v3);
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curve0 = enlargeRadiusToMinWidth(context,geom,ray.org,curve0);
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const float dt = dot(curve0.center()-ray.org,ray.dir)*rcp(dot(ray.dir,ray.dir));
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const Vec3ff ref(madd(Vec3fa(dt),ray.dir,ray.org),0.0f);
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const NativeCurve3ff curve1 = curve0-ref;
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return intersect_bezier_recursive_jacobian(ray,dt,curve1,0.0f,1.0f,1,epilog);
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}
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};
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template<template<typename Ty> class NativeCurve, int K>
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struct SweepCurve1IntersectorK
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{
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typedef NativeCurve<Vec3ff> NativeCurve3ff;
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struct Ray1
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{
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__forceinline Ray1(RayK<K>& ray, size_t k)
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: org(ray.org.x[k],ray.org.y[k],ray.org.z[k]), dir(ray.dir.x[k],ray.dir.y[k],ray.dir.z[k]), _tnear(ray.tnear()[k]), tfar(ray.tfar[k]) {}
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Vec3fa org;
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Vec3fa dir;
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float _tnear;
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float& tfar;
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__forceinline float& tnear() { return _tnear; }
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//__forceinline float& tfar() { return _tfar; }
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__forceinline const float& tnear() const { return _tnear; }
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//__forceinline const float& tfar() const { return _tfar; }
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};
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template<typename Epilog>
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__forceinline bool intersect(const CurvePrecalculationsK<K>& pre, RayK<K>& vray, size_t k,
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IntersectContext* context,
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const CurveGeometry* geom, const unsigned int primID,
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const Vec3ff& v0, const Vec3ff& v1, const Vec3ff& v2, const Vec3ff& v3,
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const Epilog& epilog)
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{
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STAT3(normal.trav_prims,1,1,1);
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Ray1 ray(vray,k);
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/* move ray closer to make intersection stable */
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NativeCurve3ff curve0(v0,v1,v2,v3);
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curve0 = enlargeRadiusToMinWidth(context,geom,ray.org,curve0);
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const float dt = dot(curve0.center()-ray.org,ray.dir)*rcp(dot(ray.dir,ray.dir));
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const Vec3ff ref(madd(Vec3fa(dt),ray.dir,ray.org),0.0f);
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const NativeCurve3ff curve1 = curve0-ref;
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return intersect_bezier_recursive_jacobian(ray,dt,curve1,0.0f,1.0f,1,epilog);
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}
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};
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}
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}
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