godot/thirdparty/embree/kernels/bvh/node_intersector_frustum.h

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

#pragma once

#include "node_intersector.h"

namespace embree
{
  namespace isa
  {
    //////////////////////////////////////////////////////////////////////////////////////
    // Frustum structure used in hybrid and stream traversal
    //////////////////////////////////////////////////////////////////////////////////////

    /*
       Optimized frustum test. We calculate t=(p-org)/dir in ray/box
       intersection. We assume the rays are split by octant, thus
       dir intervals are either positive or negative in each
       dimension.

       Case 1: dir.min >= 0 && dir.max >= 0:
         t_min = (p_min - org_max) / dir_max = (p_min - org_max)*rdir_min = p_min*rdir_min - org_max*rdir_min
         t_max = (p_max - org_min) / dir_min = (p_max - org_min)*rdir_max = p_max*rdir_max - org_min*rdir_max

       Case 2: dir.min < 0 && dir.max < 0:
         t_min = (p_max - org_min) / dir_min = (p_max - org_min)*rdir_max = p_max*rdir_max - org_min*rdir_max
         t_max = (p_min - org_max) / dir_max = (p_min - org_max)*rdir_min = p_min*rdir_min - org_max*rdir_min
    */

    template<bool robust>
    struct Frustum;
    
    /* Fast variant */
    template<>
    struct Frustum<false>
    { … };

    FrustumFast;

    /* Robust variant */
    template<>
    struct Frustum<true>
    { … };

    FrustumRobust;

    //////////////////////////////////////////////////////////////////////////////////////
    // Fast AABBNode intersection
    //////////////////////////////////////////////////////////////////////////////////////

    template<int N>
    __forceinline size_t intersectNodeFrustum(const typename BVHN<N>::AABBNode* __restrict__ node,
                                       const FrustumFast& frustum, vfloat<N>& dist)
    { … }

    //////////////////////////////////////////////////////////////////////////////////////
    // Robust AABBNode intersection
    //////////////////////////////////////////////////////////////////////////////////////

    template<int N>
    __forceinline size_t intersectNodeFrustum(const typename BVHN<N>::AABBNode* __restrict__ node,
                                       const FrustumRobust& frustum, vfloat<N>& dist)
    { … }
  }
}