inline face_verts ClipTriByPlane()

in pytorch3d/csrc/iou_box3d/iou_utils.h [429:480]

• 38 lines of code
• 25 McCabe index (conditional complexity)

inline face_verts ClipTriByPlane(
    const std::vector<vec3<float>>& plane,
    const std::vector<vec3<float>>& tri,
    const vec3<float>& normal) {
  // Get Triangle vertices
  const vec3<float> v0 = tri[0];
  const vec3<float> v1 = tri[1];
  const vec3<float> v2 = tri[2];

  // Check each of the triangle vertices to see if it is inside the plane
  const bool isin0 = IsInside(plane, normal, v0);
  const bool isin1 = IsInside(plane, normal, v1);
  const bool isin2 = IsInside(plane, normal, v2);

  // All in
  if (isin0 && isin1 && isin2) {
    // Return input vertices
    face_verts tris = {{v0, v1, v2}};
    return tris;
  }

  face_verts empty_tris = {};
  // All out
  if (!isin0 && !isin1 && !isin2) {
    return empty_tris;
  }

  // One vert out
  if (isin0 && isin1 && !isin2) {
    return ClipTriByPlaneOneOut(plane, normal, v2, v0, v1);
  }
  if (isin0 && !isin1 && isin2) {
    return ClipTriByPlaneOneOut(plane, normal, v1, v0, v2);
  }
  if (!isin0 && isin1 && isin2) {
    return ClipTriByPlaneOneOut(plane, normal, v0, v1, v2);
  }

  // Two verts out
  if (isin0 && !isin1 && !isin2) {
    return ClipTriByPlaneTwoOut(plane, normal, v1, v2, v0);
  }
  if (!isin0 && !isin1 && isin2) {
    return ClipTriByPlaneTwoOut(plane, normal, v0, v1, v2);
  }
  if (!isin0 && isin1 && !isin2) {
    return ClipTriByPlaneTwoOut(plane, normal, v0, v2, v1);
  }

  // Else return empty (should not be reached)
  return empty_tris;
}