// ======================================================================== //
// 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.                                           //
// ======================================================================== //
 
#include "grid_soa.h"

namespace embree
{
  namespace isa
  {  
    GridSOA::GridSOA(const SubdivPatch1Base* patches, unsigned time_steps, unsigned time_steps_global,
                     const unsigned x0, const unsigned x1, const unsigned y0, const unsigned y1, const unsigned swidth, const unsigned sheight,
                     const SubdivMesh* const geom, const size_t bvhBytes, const size_t gridBytes, BBox3fa* bounds_o)
      : align0(0), 
        time_steps_global(time_steps_global),time_steps(time_steps), width(x1-x0+1), height(y1-y0+1), dim_offset(width*height),
        geomID(patches->geom), primID(patches->prim), 
        bvhBytes(unsigned(bvhBytes)), gridOffset(max(1u,time_steps_global-1)*unsigned(bvhBytes)), gridBytes(unsigned(gridBytes)), rootOffset(unsigned(gridOffset+time_steps*gridBytes))
    {      
      /* the generate loops need padded arrays, thus first store into these temporary arrays */
      unsigned temp_size = width*height+VSIZEX;
      dynamic_large_stack_array(float,local_grid_u,temp_size,64*64*sizeof(float));
      dynamic_large_stack_array(float,local_grid_v,temp_size,64*64*sizeof(float));
      dynamic_large_stack_array(float,local_grid_x,temp_size,64*64*sizeof(float));
      dynamic_large_stack_array(float,local_grid_y,temp_size,64*64*sizeof(float));
      dynamic_large_stack_array(float,local_grid_z,temp_size,64*64*sizeof(float));
      dynamic_large_stack_array(float,local_grid_uv,temp_size,64*64*sizeof(float));

      /* first create the grids for each time step */
      for (size_t t=0; t<time_steps; t++)
      {
        /* compute vertex grid (+displacement) */
        evalGrid(patches[t],x0,x1,y0,y1,swidth,sheight,
                 local_grid_x,local_grid_y,local_grid_z,local_grid_u,local_grid_v,geom);
        
        /* encode UVs */
        for (unsigned i=0; i<dim_offset; i+=VSIZEX) {
          const vintx iu = (vintx) clamp(vfloatx::load(&local_grid_u[i])*0xFFFF, vfloatx(0.0f), vfloatx(0xFFFF));
          const vintx iv = (vintx) clamp(vfloatx::load(&local_grid_v[i])*0xFFFF, vfloatx(0.0f), vfloatx(0xFFFF));
          vintx::storeu(&local_grid_uv[i], (iv << 16) | iu);
        }

        /* copy temporary data to compact grid */
        float* const grid_x  = (float*)(gridData(t) + 0*dim_offset);
        float* const grid_y  = (float*)(gridData(t) + 1*dim_offset);
        float* const grid_z  = (float*)(gridData(t) + 2*dim_offset);
        int  * const grid_uv = (int*  )(gridData(t) + 3*dim_offset);
        memcpy(grid_x, local_grid_x, dim_offset*sizeof(float));
        memcpy(grid_y, local_grid_y, dim_offset*sizeof(float));
        memcpy(grid_z, local_grid_z, dim_offset*sizeof(float));
        memcpy(grid_uv,local_grid_uv,dim_offset*sizeof(int));       
      }

      /* create normal BVH when no motion blur is active */
      if (time_steps == 1) {
        root(0) = buildBVH(0,bounds_o);
      }

      /* otherwise build MBlur BVH */
      else
      {
        for (size_t t=0; t<time_steps_global-1; t++)
        {
          LBBox3fa bounds;
          root(t) = buildMBlurBVH(t,&bounds);
          if (bounds_o && time_steps == time_steps_global) {
            bounds_o[t+0] = bounds.bounds0;
            bounds_o[t+1] = bounds.bounds1;
          }
        }

        if (bounds_o && time_steps != time_steps_global)
        {
          GridRange range(0,width-1,0,height-1);
          for (size_t t=0; t<time_steps; t++)
            bounds_o[t] = calculateBounds(t,range);
        }
      }
    }

    size_t GridSOA::getBVHBytes(const GridRange& range, const size_t nodeBytes, const size_t leafBytes)
    {
      if (range.hasLeafSize()) 
        return leafBytes;
      
      __aligned(64) GridRange r[4];
      const size_t children = range.splitIntoSubRanges(r);
      
      size_t bytes = nodeBytes;
      for (size_t i=0; i<children; i++)
        bytes += getBVHBytes(r[i],nodeBytes,leafBytes);
      return bytes;
    }
    
    BVH4::NodeRef GridSOA::buildBVH(size_t time, BBox3fa* bounds_o)
    {
      BVH4::NodeRef root = 0; size_t allocator = 0;
      GridRange range(0,width-1,0,height-1);
      BBox3fa bounds = buildBVH(root,time,range,allocator);
      if (bounds_o) *bounds_o = bounds;
      assert(allocator == bvhBytes);
      return root;
    }

    BBox3fa GridSOA::buildBVH(BVH4::NodeRef& curNode, size_t time, const GridRange& range, size_t& allocator)
    {
      /*! create leaf node */
      if (unlikely(range.hasLeafSize()))
      {
        /* we store index of first subgrid vertex as leaf node */
        curNode = BVH4::encodeTypedLeaf(encodeLeaf(range.u_start,range.v_start),0);

        /* return bounding box */
        return calculateBounds(time,range);
      }
      
      /* create internal node */
      else 
      {
        /* allocate new bvh4 node */
        BVH4::AlignedNode* node = (BVH4::AlignedNode *)&bvhData(time)[allocator];
        allocator += sizeof(BVH4::AlignedNode);
        node->clear();
        
        /* split range */
        GridRange r[4];
        const unsigned children = range.splitIntoSubRanges(r);
      
        /* recurse into subtrees */
        BBox3fa bounds( empty );
        for (unsigned i=0; i<children; i++)
        {
          BBox3fa box = buildBVH( node->child(i), time, r[i], allocator);
          node->set(i,box);
          bounds.extend(box);
        }
        
        curNode = BVH4::encodeNode(node);
        assert(is_finite(bounds));
        return bounds;
      }
    }

    BVH4::NodeRef GridSOA::buildMBlurBVH(size_t time, LBBox3fa* bounds_o)
    {
      BVH4::NodeRef root = 0; size_t allocator = 0;
      GridRange range(0,width-1,0,height-1);
      LBBox3fa bounds = buildMBlurBVH(root,time,range,allocator);
      if (bounds_o) *bounds_o = bounds;
      assert(allocator == bvhBytes);
      return root;
    }

    LBBox3fa GridSOA::buildMBlurBVH(BVH4::NodeRef& curNode, size_t time, const GridRange& range, size_t& allocator)
    {
      /*! create leaf node */
      if (unlikely(range.hasLeafSize()))
      {
        /* we store index of first subgrid vertex as leaf node */
        curNode = BVH4::encodeTypedLeaf(encodeLeaf(range.u_start,range.v_start),0);

        /* return bounding box */
        return Geometry::linearBounds([&] (size_t itime) { return calculateBounds(itime,range); },
                                      time, time_steps_global, time_steps);
      }
      
      /* create internal node */
      else 
      {
        /* allocate new bvh4 node */
        BVH4::AlignedNodeMB* node = (BVH4::AlignedNodeMB *)&bvhData(time)[allocator];
        allocator += sizeof(BVH4::AlignedNodeMB);
        node->clear();
        
        /* split range */
        GridRange r[4];
        const unsigned children = range.splitIntoSubRanges(r);
      
        /* recurse into subtrees */
        LBBox3fa bounds(empty);
        for (unsigned i=0; i<children; i++)
        {
          LBBox3fa box = buildMBlurBVH(node->child(i), time, r[i], allocator);
          node->set(i, box);
          bounds.extend(box);
        }
        
        curNode = BVH4::encodeNode(node);
        assert(is_finite(bounds.bounds0));
        assert(is_finite(bounds.bounds1));
        return bounds;
      }
    }
  }
}