// Copyright 2009-2021 Intel Corporation
// SPDX-License-Identifier: Apache-2.0

#pragma once

#include "primitive.h"

namespace embree
{
  /* Stores the vertices of M triangles in struct of array layout */
  template<int M>
  struct TriangleMvMB
  {
  public:
    struct Type : public PrimitiveType 
    {
      const char* name() const;
      size_t sizeActive(const char* This) const;
      size_t sizeTotal(const char* This) const;
      size_t getBytes(const char* This) const;
    };

    static Type type;

  public:

    /* primitive supports single time segments */
    static const bool singleTimeSegment = true;

    /* Returns maximum number of stored triangles */
    static __forceinline size_t max_size() { return M; }
    
    /* Returns required number of primitive blocks for N primitives */
    static __forceinline size_t blocks(size_t N) { return (N+max_size()-1)/max_size(); }
   
  public:

    /* Default constructor */
    __forceinline TriangleMvMB() {}

    /* Construction from vertices and IDs */
    __forceinline TriangleMvMB(const Vec3vf<M>& a0, const Vec3vf<M>& a1,
                               const Vec3vf<M>& b0, const Vec3vf<M>& b1,
                               const Vec3vf<M>& c0, const Vec3vf<M>& c1,
                               const vuint<M>& geomIDs, const vuint<M>& primIDs)
      : v0(a0), v1(b0), v2(c0), dv0(a1-a0), dv1(b1-b0), dv2(c1-c0), geomIDs(geomIDs), primIDs(primIDs) {}

    /* Returns a mask that tells which triangles are valid */
    __forceinline vbool<M> valid() const { return geomIDs != vuint<M>(-1); }

    /* Returns if the specified triangle is valid */
    __forceinline bool valid(const size_t i) const { assert(i<M); return geomIDs[i] != -1; }

    /* Returns the number of stored triangles */
    __forceinline size_t size() const { return bsf(~movemask(valid())); }

    /* Returns the geometry IDs */
    __forceinline       vuint<M>& geomID()       { return geomIDs; }
    __forceinline const vuint<M>& geomID() const { return geomIDs; }
    __forceinline unsigned int geomID(const size_t i) const { assert(i<M); return geomIDs[i]; }

    /* Returns the primitive IDs */
    __forceinline       vuint<M>& primID()       { return primIDs; }
    __forceinline const vuint<M>& primID() const { return primIDs; }
    __forceinline unsigned int primID(const size_t i) const { assert(i<M); return primIDs[i]; }

    /* Calculate the bounds of the triangles at t0 */
    __forceinline BBox3fa bounds0() const 
    {
      Vec3vf<M> lower = min(v0,v1,v2);
      Vec3vf<M> upper = max(v0,v1,v2);
      const vbool<M> mask = valid();
      lower.x = select(mask,lower.x,vfloat<M>(pos_inf));
      lower.y = select(mask,lower.y,vfloat<M>(pos_inf));
      lower.z = select(mask,lower.z,vfloat<M>(pos_inf));
      upper.x = select(mask,upper.x,vfloat<M>(neg_inf));
      upper.y = select(mask,upper.y,vfloat<M>(neg_inf));
      upper.z = select(mask,upper.z,vfloat<M>(neg_inf));
      return BBox3fa(Vec3fa(reduce_min(lower.x),reduce_min(lower.y),reduce_min(lower.z)),
		     Vec3fa(reduce_max(upper.x),reduce_max(upper.y),reduce_max(upper.z)));
    }

    /* Calculate the bounds of the triangles at t1 */
    __forceinline BBox3fa bounds1() const 
    {
      const Vec3vf<M> p0 = v0+dv0;
      const Vec3vf<M> p1 = v1+dv1;
      const Vec3vf<M> p2 = v2+dv2;
      Vec3vf<M> lower = min(p0,p1,p2);
      Vec3vf<M> upper = max(p0,p1,p2);
      const vbool<M> mask = valid();
      lower.x = select(mask,lower.x,vfloat<M>(pos_inf));
      lower.y = select(mask,lower.y,vfloat<M>(pos_inf));
      lower.z = select(mask,lower.z,vfloat<M>(pos_inf));
      upper.x = select(mask,upper.x,vfloat<M>(neg_inf));
      upper.y = select(mask,upper.y,vfloat<M>(neg_inf));
      upper.z = select(mask,upper.z,vfloat<M>(neg_inf));
      return BBox3fa(Vec3fa(reduce_min(lower.x),reduce_min(lower.y),reduce_min(lower.z)),
		     Vec3fa(reduce_max(upper.x),reduce_max(upper.y),reduce_max(upper.z)));
    }

    /* Calculate the linear bounds of the primitive */
    __forceinline LBBox3fa linearBounds() const {
      return LBBox3fa(bounds0(),bounds1());
    }

    /* Fill triangle from triangle list */
    __forceinline LBBox3fa fillMB(const PrimRef* prims, size_t& begin, size_t end, Scene* scene, size_t itime)
    {
      vuint<M> vgeomID = -1, vprimID = -1;
      Vec3vf<M> va0 = zero, vb0 = zero, vc0 = zero;
      Vec3vf<M> va1 = zero, vb1 = zero, vc1 = zero;

      BBox3fa bounds0 = empty;
      BBox3fa bounds1 = empty;
      for (size_t i=0; i<M && begin<end; i++, begin++)
      {
	const PrimRef& prim = prims[begin];
        const unsigned geomID = prim.geomID();
        const unsigned primID = prim.primID();
        const TriangleMesh* __restrict__ const mesh = scene->get<TriangleMesh>(geomID);
        const TriangleMesh::Triangle& tri = mesh->triangle(primID);
        const Vec3fa& a0 = mesh->vertex(tri.v[0],size_t(itime+0)); bounds0.extend(a0);
        const Vec3fa& a1 = mesh->vertex(tri.v[0],size_t(itime+1)); bounds1.extend(a1);
        const Vec3fa& b0 = mesh->vertex(tri.v[1],size_t(itime+0)); bounds0.extend(b0);
        const Vec3fa& b1 = mesh->vertex(tri.v[1],size_t(itime+1)); bounds1.extend(b1);
        const Vec3fa& c0 = mesh->vertex(tri.v[2],size_t(itime+0)); bounds0.extend(c0);
        const Vec3fa& c1 = mesh->vertex(tri.v[2],size_t(itime+1)); bounds1.extend(c1);
        vgeomID [i] = geomID;
        vprimID [i] = primID;
        va0.x[i] = a0.x; va0.y[i] = a0.y; va0.z[i] = a0.z;
	va1.x[i] = a1.x; va1.y[i] = a1.y; va1.z[i] = a1.z;
	vb0.x[i] = b0.x; vb0.y[i] = b0.y; vb0.z[i] = b0.z;
	vb1.x[i] = b1.x; vb1.y[i] = b1.y; vb1.z[i] = b1.z;
	vc0.x[i] = c0.x; vc0.y[i] = c0.y; vc0.z[i] = c0.z;
	vc1.x[i] = c1.x; vc1.y[i] = c1.y; vc1.z[i] = c1.z;
      }
      new (this) TriangleMvMB(va0,va1,vb0,vb1,vc0,vc1,vgeomID,vprimID);
      return LBBox3fa(bounds0,bounds1);
    }

    /* Fill triangle from triangle list */
    __forceinline LBBox3fa fillMB(const PrimRefMB* prims, size_t& begin, size_t end, Scene* scene, const BBox1f time_range)
    {
      vuint<M> vgeomID = -1, vprimID = -1;
      Vec3vf<M> va0 = zero, vb0 = zero, vc0 = zero;
      Vec3vf<M> va1 = zero, vb1 = zero, vc1 = zero;

      LBBox3fa allBounds = empty;
      for (size_t i=0; i<M && begin<end; i++, begin++)
      {
        const PrimRefMB& prim = prims[begin];
        const unsigned geomID = prim.geomID();
        const unsigned primID = prim.primID();
        const TriangleMesh* const mesh = scene->get<TriangleMesh>(geomID);
        const range<int> itime_range = mesh->timeSegmentRange(time_range);
        assert(itime_range.size() == 1);
        const int ilower = itime_range.begin();
        const TriangleMesh::Triangle& tri = mesh->triangle(primID);
        allBounds.extend(mesh->linearBounds(primID, time_range));
        const Vec3fa& a0 = mesh->vertex(tri.v[0],size_t(ilower+0));
        const Vec3fa& a1 = mesh->vertex(tri.v[0],size_t(ilower+1));
        const Vec3fa& b0 = mesh->vertex(tri.v[1],size_t(ilower+0));
        const Vec3fa& b1 = mesh->vertex(tri.v[1],size_t(ilower+1));
        const Vec3fa& c0 = mesh->vertex(tri.v[2],size_t(ilower+0));
        const Vec3fa& c1 = mesh->vertex(tri.v[2],size_t(ilower+1));
        const BBox1f time_range_v(mesh->timeStep(ilower+0),mesh->timeStep(ilower+1));
        auto a01 = globalLinear(std::make_pair(a0,a1),time_range_v);
        auto b01 = globalLinear(std::make_pair(b0,b1),time_range_v);
        auto c01 = globalLinear(std::make_pair(c0,c1),time_range_v);
        vgeomID [i] = geomID;
        vprimID [i] = primID;
        va0.x[i] = a01.first .x; va0.y[i] = a01.first .y; va0.z[i] = a01.first .z;
	va1.x[i] = a01.second.x; va1.y[i] = a01.second.y; va1.z[i] = a01.second.z;
	vb0.x[i] = b01.first .x; vb0.y[i] = b01.first .y; vb0.z[i] = b01.first .z;
	vb1.x[i] = b01.second.x; vb1.y[i] = b01.second.y; vb1.z[i] = b01.second.z;
	vc0.x[i] = c01.first .x; vc0.y[i] = c01.first .y; vc0.z[i] = c01.first .z;
	vc1.x[i] = c01.second.x; vc1.y[i] = c01.second.y; vc1.z[i] = c01.second.z;
      }
      new (this) TriangleMvMB(va0,va1,vb0,vb1,vc0,vc1,vgeomID,vprimID);
      return allBounds;
    }

  public:
    Vec3vf<M> v0;      // 1st vertex of the triangles
    Vec3vf<M> v1;      // 2nd vertex of the triangles
    Vec3vf<M> v2;      // 3rd vertex of the triangles
    Vec3vf<M> dv0;     // difference vector between time steps t0 and t1 for first vertex
    Vec3vf<M> dv1;     // difference vector between time steps t0 and t1 for second vertex
    Vec3vf<M> dv2;     // difference vector between time steps t0 and t1 for third vertex
  private:
    vuint<M> geomIDs; // geometry ID
    vuint<M> primIDs; // primitive ID
  };

  template<int M>
  typename TriangleMvMB<M>::Type TriangleMvMB<M>::type;

  typedef TriangleMvMB<4> Triangle4vMB;
}