dali-scene3d/internal/algorithm/path-finder-spfa.cpp

   1 /*
   2  * Copyright (c) 2023 Samsung Electronics Co., Ltd.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 // CLASS HEADER
  18 #include <dali-scene3d/internal/algorithm/path-finder-spfa.h>
  19
  20 // EXTERNAL INCLUDES
  21 #include <dali/public-api/common/vector-wrapper.h>
  22 #include <limits>
  23
  24 // INTERNAL INCLUDES
  25 #include <dali-scene3d/internal/algorithm/path-finder-waypoint-data.h>
  26 #include <dali-scene3d/public-api/algorithm/path-finder-waypoint.h>
  27
  28 using WayPointList = Dali::Scene3D::Algorithm::WayPointList;
  29
  30 namespace Dali::Scene3D::Internal::Algorithm
  31 {
  32 PathFinderAlgorithmSPFA::PathFinderAlgorithmSPFA(Dali::Scene3D::Algorithm::NavigationMesh& navMesh)
  33 : mNavigationMesh(&GetImplementation(navMesh))
  34 {
  35   PrepareData();
  36 }
  37
  38 PathFinderAlgorithmSPFA::~PathFinderAlgorithmSPFA() = default;
  39
  40 Scene3D::Algorithm::WayPointList PathFinderAlgorithmSPFA::FindPath(const Dali::Vector3& positionFrom, const Dali::Vector3& positionTo)
  41 {
  42   Dali::Vector3 outPosFrom;
  43   FaceIndex     polyIndexFrom;
  44   auto          result = mNavigationMesh->FindFloor(positionFrom, outPosFrom, polyIndexFrom);
  45
  46   Scene3D::Algorithm::WayPointList waypoints;
  47
  48   if(result)
  49   {
  50     Dali::Vector3 outPosTo;
  51     FaceIndex     polyIndexTo;
  52     result = mNavigationMesh->FindFloor(positionTo, outPosTo, polyIndexTo);
  53
  54     if(result)
  55     {
  56       // Get waypoints
  57       waypoints = FindPath(polyIndexFrom, polyIndexTo);
  58
  59       // replace first and last waypoint
  60       auto& wpFrom = static_cast<WayPointData&>(waypoints[0]);
  61       auto& wpTo   = static_cast<WayPointData&>(waypoints.back());
  62
  63       Vector2 fromCenter(wpFrom.point3d.x, wpFrom.point3d.y);
  64       wpFrom.point3d = outPosFrom;
  65       wpFrom.point2d = fromCenter - Vector2(outPosFrom.x, outPosFrom.y);
  66
  67       Vector2 toCenter(wpTo.point3d.x, wpTo.point3d.y);
  68       wpTo.point3d = outPosTo;
  69       wpTo.point2d = toCenter - Vector2(outPosTo.x, outPosTo.y);
  70       wpTo.point3d = outPosTo;
  71     }
  72   }
  73
  74   // Returns waypoints with non-zero size of empty vector in case of failure (no path to be found)
  75   return waypoints;
  76 }
  77
  78 Scene3D::Algorithm::WayPointList PathFinderAlgorithmSPFA::FindPath(FaceIndex sourcePolyIndex, FaceIndex targetPolyIndex)
  79 {
  80   auto                   nodeCount = uint32_t(mNodes.size());
  81   std::vector<float>     dist;
  82   std::vector<FaceIndex> prev;
  83   std::vector<bool>      queued;
  84
  85   dist.resize(mNodes.size());
  86   prev.resize(mNodes.size());
  87   queued.resize(mNodes.size());
  88
  89   std::list<FaceIndex> nodeQueue;
  90
  91   [[maybe_unused]] auto sourcePos = Dali::Vector3(Face(sourcePolyIndex)->center);
  92
  93   for(auto i = 0u; i < nodeCount; ++i)
  94   {
  95     dist[i]   = std::numeric_limits<float>::infinity();
  96     prev[i]   = Scene3D::Algorithm::NavigationMesh::NULL_FACE; // set prev to null polygon
  97     queued[i] = false;
  98   }
  99
 100   // Set distance of source
 101   dist[sourcePolyIndex]   = 0.0f;
 102   queued[sourcePolyIndex] = true;
 103   nodeQueue.push_back(sourcePolyIndex);
 104
 105   while(!nodeQueue.empty())
 106   {
 107     // find minimum distance
 108     auto minDistIndex = nodeQueue.front();
 109     nodeQueue.pop_front();
 110     queued[minDistIndex] = false;
 111
 112     // Skip operator when minDistIndex is target
 113     if(minDistIndex == targetPolyIndex)
 114     {
 115       continue;
 116     }
 117
 118     // check the neighbours
 119     for(auto i = 0u; i < 3; ++i)
 120     {
 121       auto nIndex = mNodes[minDistIndex].faces[i];
 122       if(nIndex != Scene3D::Algorithm::NavigationMesh::NULL_FACE)
 123       {
 124         auto alt = dist[minDistIndex] + mNodes[minDistIndex].weight[i];
 125         if(alt < dist[nIndex])
 126         {
 127           dist[nIndex] = alt;
 128           prev[nIndex] = minDistIndex;
 129
 130           if(!queued[nIndex])
 131           {
 132             queued[nIndex] = true;
 133             if(!nodeQueue.empty() && dist[nIndex] < dist[nodeQueue.front()])
 134             {
 135               nodeQueue.push_front(nIndex);
 136             }
 137             else
 138             {
 139               nodeQueue.push_back(nIndex);
 140             }
 141           }
 142         }
 143       }
 144     }
 145   }
 146
 147   // Compute distances for each node back to the source
 148   auto                 u = targetPolyIndex;
 149   std::list<FaceIndex> q;
 150   if(prev[u] != Scene3D::Algorithm::NavigationMesh::NULL_FACE || u == sourcePolyIndex)
 151   {
 152     while(u != Scene3D::Algorithm::NavigationMesh::NULL_FACE)
 153     {
 154       q.push_front(u);
 155       u = prev[u];
 156     }
 157   }
 158
 159   WayPointList waypoints;
 160   waypoints.resize(q.size());
 161
 162   if(q.size() == 0)
 163   {
 164     // Fail to found path. Return empty list.
 165     return waypoints;
 166   }
 167
 168   auto index = 0u;
 169   auto prevN = 0u;
 170   for(auto n : q)
 171   {
 172     auto& wp     = static_cast<WayPointData&>(waypoints[index]);
 173     wp.face      = mNavigationMesh->GetFace(n);
 174     wp.nodeIndex = n;
 175
 176     wp.edge = nullptr;
 177     // set the common edge with previous node
 178     if(index > 0)
 179     {
 180       const auto& node = mNodes[prevN];
 181       for(auto i = 0u; i < 3; ++i)
 182       {
 183         if(node.faces[i] == wp.nodeIndex)
 184         {
 185           wp.edge = mNavigationMesh->GetEdge(node.edges[i]);
 186           break;
 187         }
 188       }
 189     }
 190
 191     prevN = n;
 192     index++;
 193   }
 194
 195   return OptimizeWaypoints(waypoints);
 196 }
 197
 198 void PathFinderAlgorithmSPFA::PrepareData()
 199 {
 200   // Build the list structure connecting the nodes
 201   auto faceCount = mNavigationMesh->GetFaceCount();
 202
 203   mNodes.resize(faceCount);
 204
 205   // for each face build the list
 206   // TODO : Currently, we are assume that FaceNodeIndex is matched with FaceIndex 1:1. This might be changed in future.
 207   for(FaceNodeIndex i = 0u; i < faceCount; ++i)
 208   {
 209     auto&       node = mNodes[i];
 210     const auto* face = mNavigationMesh->GetFace(i);
 211     auto        c0   = Dali::Vector3(face->center);
 212
 213     // for each edge add neighbouring face and compute distance to set the weight of node
 214     for(auto edgeIndex = 0u; edgeIndex < 3; ++edgeIndex)
 215     {
 216       const auto* edge = mNavigationMesh->GetEdge(face->edge[edgeIndex]);
 217       auto        p1   = edge->face[0];
 218       auto        p2   = edge->face[1];
 219
 220       // One of faces is current face so ignore it
 221       auto p                = ((p1 != i) ? p1 : p2);
 222       node.faces[edgeIndex] = p;
 223       if(p != ::Dali::Scene3D::Algorithm::NavigationMesh::NULL_FACE)
 224       {
 225         node.edges[edgeIndex]  = face->edge[edgeIndex];
 226         auto c1                = Dali::Vector3(mNavigationMesh->GetFace(p)->center);
 227         node.weight[edgeIndex] = (c1 - c0).Length();
 228       }
 229     }
 230   }
 231 }
 232
 233 [[maybe_unused]] static float ccw(const Dali::Vector2& A, const Dali::Vector2& B, const Dali::Vector2& C)
 234 {
 235   return (C.y - A.y) * (B.x - A.x) > (B.y - A.y) * (C.x - A.x);
 236 }
 237
 238 [[maybe_unused]] static bool intersect(const Dali::Vector2& A, const Dali::Vector2& B, const Dali::Vector2& C, const Dali::Vector2& D)
 239 {
 240   return ccw(A, C, D) != ccw(B, C, D) && ccw(A, B, C) != ccw(A, B, D);
 241 }
 242
 243 Scene3D::Algorithm::WayPointList PathFinderAlgorithmSPFA::OptimizeWaypoints(WayPointList& waypoints) const
 244 {
 245   WayPointList optimizedWaypoints;
 246   optimizedWaypoints.emplace_back(waypoints[0]);
 247   optimizedWaypoints.reserve(waypoints.size());
 248
 249   auto startIndex = 1u;
 250
 251   bool finished = false;
 252   for(auto j = 0; !finished; ++j)
 253   {
 254     auto&       startWaypoint     = optimizedWaypoints.back();
 255     const auto& startWaypointData = static_cast<const WayPointData&>(startWaypoint);
 256
 257     // add new-last waypoint which will be overriden as long as intersection takes place
 258     optimizedWaypoints.emplace_back();
 259     for(auto wpIndex = startIndex; wpIndex < waypoints.size(); ++wpIndex)
 260     {
 261       if(wpIndex == waypoints.size() - 1)
 262       {
 263         optimizedWaypoints.back() = waypoints.back();
 264         finished                  = true;
 265         continue;
 266       }
 267       // Points between centres of faces
 268
 269       const auto& wpData = static_cast<const WayPointData&>(waypoints[wpIndex]);
 270
 271       auto Pa0 = Dali::Vector2(startWaypointData.face->center[0], startWaypointData.face->center[1]);
 272       auto Pa1 = Dali::Vector2(wpData.face->center[0], wpData.face->center[1]);
 273
 274       bool doesIntersect = true;
 275       for(auto i = startIndex; i < wpIndex; ++i)
 276       {
 277         const auto& wp = static_cast<WayPointData&>(waypoints[i]);
 278         // Skip starting waypoint
 279         if(wp.face == startWaypointData.face)
 280         {
 281           continue;
 282         }
 283         auto Pb0  = mNavigationMesh->GetVertex(wp.edge->vertex[0]);
 284         auto Pb1  = mNavigationMesh->GetVertex(wp.edge->vertex[1]);
 285         auto vPb0 = Dali::Vector2(Pb0->x, Pb0->y);
 286         auto vPb1 = Dali::Vector2(Pb1->x, Pb1->y);
 287
 288         doesIntersect = intersect(Pa0, Pa1, vPb0, vPb1);
 289         if(!doesIntersect)
 290         {
 291           break;
 292         }
 293       }
 294
 295       if(!doesIntersect)
 296       {
 297         optimizedWaypoints.back() = waypoints[wpIndex - 1];
 298         startIndex                = wpIndex - 1;
 299         break;
 300       }
 301     }
 302   }
 303
 304   for(auto& wp : optimizedWaypoints)
 305   {
 306     auto& wpData   = static_cast<WayPointData&>(wp);
 307     wpData.point3d = mNavigationMesh->PointLocalToScene(Dali::Vector3(wpData.face->center));
 308     wpData.point2d = Vector2::ZERO;
 309   }
 310
 311   return optimizedWaypoints;
 312 }
 313 } // namespace Dali::Scene3D::Internal::Algorithm