Function rtcBuildBVHSpatialSAH

kernels/common/rtcore_builder.cpp:217–335

    }

    void* rtcBuildBVHSpatialSAH(const RTCBuildArguments* arguments)
    {
      BVH* bvh = (BVH*) arguments->bvh;
      RTCBuildPrimitive* prims =  arguments->primitives;
      size_t primitiveCount = arguments->primitiveCount;
      RTCCreateNodeFunction createNode = arguments->createNode;
      RTCSetNodeChildrenFunction setNodeChildren = arguments->setNodeChildren;
      RTCSetNodeBoundsFunction setNodeBounds = arguments->setNodeBounds;
      RTCCreateLeafFunction createLeaf = arguments->createLeaf;
      RTCSplitPrimitiveFunction splitPrimitive = arguments->splitPrimitive;
      RTCProgressMonitorFunction buildProgress = arguments->buildProgress;
      void* userPtr = arguments->userPtr;
      
      std::atomic<size_t> progress(0);
  
      /* calculate priminfo */

      auto computeBounds = [&](const range<size_t>& r) -> std::pair<CentGeomBBox3fa,unsigned int>
        {
          CentGeomBBox3fa bounds(empty);
          unsigned maxGeomID = 0;
          for (size_t j=r.begin(); j<r.end(); j++)
          {
            bounds.extend((BBox3fa&)prims[j]);
            maxGeomID = max(maxGeomID,prims[j].geomID);
          }
          return std::pair<CentGeomBBox3fa,unsigned int>(bounds,maxGeomID);
        };


      const std::pair<CentGeomBBox3fa,unsigned int> pair = 
        parallel_reduce(size_t(0),primitiveCount,size_t(1024),size_t(1024),std::pair<CentGeomBBox3fa,unsigned int>(CentGeomBBox3fa(empty),0), computeBounds, mergePair);

      CentGeomBBox3fa bounds = pair.first;
      const unsigned int maxGeomID = pair.second;
      
      if (unlikely(maxGeomID >= ((unsigned int)1 << (32-RESERVED_NUM_SPATIAL_SPLITS_GEOMID_BITS))))
        {
          /* fallback code for max geomID larger than threshold */
          return rtcBuildBVHBinnedSAH(arguments);
        }

      const PrimInfo pinfo(0,primitiveCount,bounds);

      /* function that splits a build primitive */
      struct Splitter
      {
        Splitter (RTCSplitPrimitiveFunction splitPrimitive, unsigned geomID, unsigned primID, void* userPtr)
          : splitPrimitive(splitPrimitive), geomID(geomID), primID(primID), userPtr(userPtr) {}
        
        __forceinline void operator() (PrimRef& prim, const size_t dim, const float pos, PrimRef& left_o, PrimRef& right_o) const 
        {
          prim.geomIDref() &= BVHBuilderBinnedFastSpatialSAH::GEOMID_MASK;
          splitPrimitive((RTCBuildPrimitive*)&prim,(unsigned)dim,pos,(RTCBounds*)&left_o,(RTCBounds*)&right_o,userPtr);
          left_o.geomIDref()  = geomID; left_o.primIDref()  = primID;
          right_o.geomIDref() = geomID; right_o.primIDref() = primID;
        }