// ======================================================================== //
// Copyright 2009-2017 Intel Corporation                                    //
//                                                                          //
// Licensed under the Apache License, Version 2.0 (the "License");          //
// you may not use this file except in compliance with the License.         //
// You may obtain a copy of the License at                                  //
//                                                                          //
//     http://www.apache.org/licenses/LICENSE-2.0                           //
//                                                                          //
// Unless required by applicable law or agreed to in writing, software      //
// distributed under the License is distributed on an "AS IS" BASIS,        //
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. //
// See the License for the specific language governing permissions and      //
// limitations under the License.                                           //
// ======================================================================== //

#pragma once

#include "primitive.h"

namespace embree
{
  /* Stores the vertices of M triangles in struct of array layout */
  template<int M>
  struct TriangleMvMB
  {
    typedef Vec3<vfloat<M>> Vec3vfM;

  public:
    struct Type : public PrimitiveType 
    {
      Type();
      size_t size(const char* This) const;
    };

    static Type type;

  public:
    
    /* Returns maximal 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 Vec3vfM& a0, const Vec3vfM& a1,
                               const Vec3vfM& b0, const Vec3vfM& b1,
                               const Vec3vfM& c0, const Vec3vfM& c1,
                               const vint<M>& geomIDs, const vint<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 != vint<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 vint<M> geomID() const { return geomIDs; }
    __forceinline int geomID(const size_t i) const { assert(i<M); return geomIDs[i]; }

    /* Returns the primitive IDs */
    __forceinline vint<M> primID() const { return primIDs; }
    __forceinline 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 
    {
      Vec3vfM lower = min(v0,v1,v2);
      Vec3vfM 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 Vec3vfM p0 = v0+dv0;
      const Vec3vfM p1 = v1+dv1;
      const Vec3vfM p2 = v2+dv2;
      Vec3vfM lower = min(p0,p1,p2);
      Vec3vfM 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, size_t numTimeSteps)
    {
      vint<M> vgeomID = -1, vprimID = -1;
      Vec3vfM va0 = zero, vb0 = zero, vc0 = zero;
      Vec3vfM 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);
        if (unlikely(mesh->numTimeSteps != numTimeSteps))
          throw_RTCError(RTC_INVALID_OPERATION, "TriangleMvMB is not supported for different number of time steps per mesh");
        const TriangleMesh::Triangle& tri = mesh->triangle(primID);
        const Vec3fa& a0 = mesh->vertex(tri.v[0],itime+0); bounds0.extend(a0);
        const Vec3fa& a1 = mesh->vertex(tri.v[0],itime+1); bounds1.extend(a1);
        const Vec3fa& b0 = mesh->vertex(tri.v[1],itime+0); bounds0.extend(b0);
        const Vec3fa& b1 = mesh->vertex(tri.v[1],itime+1); bounds1.extend(b1);
        const Vec3fa& c0 = mesh->vertex(tri.v[2],itime+0); bounds0.extend(c0);
        const Vec3fa& c1 = mesh->vertex(tri.v[2],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);
    }
   
  public:
    Vec3vfM v0;      // 1st vertex of the triangles
    Vec3vfM v1;      // 2nd vertex of the triangles
    Vec3vfM v2;      // 3rd vertex of the triangles
    Vec3vfM dv0;     // difference vector between time steps t0 and t1 for first vertex
    Vec3vfM dv1;     // difference vector between time steps t0 and t1 for second vertex
    Vec3vfM dv2;     // difference vector between time steps t0 and t1 for third vertex
    vint<M> geomIDs; // geometry ID
    vint<M> primIDs; // primitive ID
  };

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

  typedef TriangleMvMB<4> Triangle4vMB;
}