132 lines
5.4 KiB
C++
132 lines
5.4 KiB
C++
// Copyright 2009-2020 Intel Corporation
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// SPDX-License-Identifier: Apache-2.0
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#include "primitive.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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struct TriangleTriangleIntersector
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{
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__forceinline static float T(float pa0, float pa1, float da0, float da1) {
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return pa0 + (pa1-pa0)*da0/(da0-da1);
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}
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__forceinline static bool point_line_side(const Vec2f& p, const Vec2f& a0, const Vec2f& a1) {
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return det(p-a0,a0-a1) >= 0.0f;
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}
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__forceinline static bool point_inside_triangle(const Vec2f& p, const Vec2f& a, const Vec2f& b, const Vec2f& c)
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{
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const bool pab = point_line_side(p,a,b);
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const bool pbc = point_line_side(p,b,c);
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const bool pca = point_line_side(p,c,a);
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return pab == pbc && pab == pca;
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}
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__forceinline static bool intersect_line_line(const Vec2f& a0, const Vec2f& a1, const Vec2f& b0, const Vec2f& b1)
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{
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const bool different_sides0 = point_line_side(b0,a0,a1) != point_line_side(b1,a0,a1);
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const bool different_sides1 = point_line_side(a0,b0,b1) != point_line_side(a1,b0,b1);
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return different_sides0 && different_sides1;
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}
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__forceinline static bool intersect_triangle_triangle (const Vec2f& a0, const Vec2f& a1, const Vec2f& a2,
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const Vec2f& b0, const Vec2f& b1, const Vec2f& b2)
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{
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const bool a01_b01 = intersect_line_line(a0,a1,b0,b1);
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if (a01_b01) return true;
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const bool a01_b12 = intersect_line_line(a0,a1,b1,b2);
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if (a01_b12) return true;
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const bool a01_b20 = intersect_line_line(a0,a1,b2,b0);
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if (a01_b20) return true;
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const bool a12_b01 = intersect_line_line(a1,a2,b0,b1);
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if (a12_b01) return true;
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const bool a12_b12 = intersect_line_line(a1,a2,b1,b2);
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if (a12_b12) return true;
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const bool a12_b20 = intersect_line_line(a1,a2,b2,b0);
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if (a12_b20) return true;
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const bool a20_b01 = intersect_line_line(a2,a0,b0,b1);
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if (a20_b01) return true;
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const bool a20_b12 = intersect_line_line(a2,a0,b1,b2);
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if (a20_b12) return true;
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const bool a20_b20 = intersect_line_line(a2,a0,b2,b0);
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if (a20_b20) return true;
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bool a_in_b = point_inside_triangle(a0,b0,b1,b2) && point_inside_triangle(a1,b0,b1,b2) && point_inside_triangle(a2,b0,b1,b2);
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if (a_in_b) return true;
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bool b_in_a = point_inside_triangle(b0,a0,a1,a2) && point_inside_triangle(b1,a0,a1,a2) && point_inside_triangle(b2,a0,a1,a2);
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if (b_in_a) return true;
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return false;
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}
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static bool intersect_triangle_triangle (const Vec3fa& a0, const Vec3fa& a1, const Vec3fa& a2,
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const Vec3fa& b0, const Vec3fa& b1, const Vec3fa& b2)
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{
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const float eps = 1E-5f;
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/* calculate triangle planes */
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const Vec3fa Na = cross(a1-a0,a2-a0);
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const float Ca = dot(Na,a0);
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const Vec3fa Nb = cross(b1-b0,b2-b0);
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const float Cb = dot(Nb,b0);
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/* project triangle A onto plane B */
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const float da0 = dot(Nb,a0)-Cb;
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const float da1 = dot(Nb,a1)-Cb;
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const float da2 = dot(Nb,a2)-Cb;
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if (max(da0,da1,da2) < -eps) return false;
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if (min(da0,da1,da2) > +eps) return false;
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//CSTAT(bvh_collide_prim_intersections4++);
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/* project triangle B onto plane A */
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const float db0 = dot(Na,b0)-Ca;
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const float db1 = dot(Na,b1)-Ca;
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const float db2 = dot(Na,b2)-Ca;
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if (max(db0,db1,db2) < -eps) return false;
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if (min(db0,db1,db2) > +eps) return false;
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//CSTAT(bvh_collide_prim_intersections5++);
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if (unlikely((std::fabs(da0) < eps && std::fabs(da1) < eps && std::fabs(da2) < eps) ||
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(std::fabs(db0) < eps && std::fabs(db1) < eps && std::fabs(db2) < eps)))
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{
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const size_t dz = maxDim(Na);
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const size_t dx = (dz+1)%3;
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const size_t dy = (dx+1)%3;
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const Vec2f A0(a0[dx],a0[dy]);
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const Vec2f A1(a1[dx],a1[dy]);
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const Vec2f A2(a2[dx],a2[dy]);
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const Vec2f B0(b0[dx],b0[dy]);
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const Vec2f B1(b1[dx],b1[dy]);
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const Vec2f B2(b2[dx],b2[dy]);
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return intersect_triangle_triangle(A0,A1,A2,B0,B1,B2);
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}
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const Vec3fa D = cross(Na,Nb);
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const float pa0 = dot(D,a0);
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const float pa1 = dot(D,a1);
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const float pa2 = dot(D,a2);
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const float pb0 = dot(D,b0);
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const float pb1 = dot(D,b1);
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const float pb2 = dot(D,b2);
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BBox1f ba = empty;
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if (min(da0,da1) <= 0.0f && max(da0,da1) >= 0.0f && abs(da0-da1) > 0.0f) ba.extend(T(pa0,pa1,da0,da1));
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if (min(da1,da2) <= 0.0f && max(da1,da2) >= 0.0f && abs(da1-da2) > 0.0f) ba.extend(T(pa1,pa2,da1,da2));
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if (min(da2,da0) <= 0.0f && max(da2,da0) >= 0.0f && abs(da2-da0) > 0.0f) ba.extend(T(pa2,pa0,da2,da0));
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BBox1f bb = empty;
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if (min(db0,db1) <= 0.0f && max(db0,db1) >= 0.0f && abs(db0-db1) > 0.0f) bb.extend(T(pb0,pb1,db0,db1));
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if (min(db1,db2) <= 0.0f && max(db1,db2) >= 0.0f && abs(db1-db2) > 0.0f) bb.extend(T(pb1,pb2,db1,db2));
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if (min(db2,db0) <= 0.0f && max(db2,db0) >= 0.0f && abs(db2-db0) > 0.0f) bb.extend(T(pb2,pb0,db2,db0));
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return conjoint(ba,bb);
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}
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};
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}
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}
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