stk-code_catmod/src/tracks/arena_graph.cpp

457 lines
16 KiB
C++

//
// SuperTuxKart - a fun racing game with go-kart
// Copyright (C) 2016 SuperTuxKart Team
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 3
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#include "tracks/arena_graph.hpp"
#include "config/user_config.hpp"
#include "io/file_manager.hpp"
#include "io/xml_node.hpp"
#include "race/race_manager.hpp"
#include "tracks/arena_node.hpp"
#include "tracks/track.hpp"
#include "tracks/track_manager.hpp"
#include "utils/log.hpp"
#include <algorithm>
#include <queue>
// -----------------------------------------------------------------------------
ArenaGraph::ArenaGraph(const std::string &navmesh, const XMLNode *node)
: Graph()
{
loadNavmesh(navmesh);
buildGraph();
// Compute shortest distance from all nodes
for (unsigned int i = 0; i < getNumNodes(); i++)
computeDijkstra(i);
setNearbyNodesOfAllNodes();
if (node && race_manager->getMinorMode() == RaceManager::MINOR_MODE_SOCCER)
loadGoalNodes(node);
loadBoundingBoxNodes();
} // ArenaGraph
// -----------------------------------------------------------------------------
ArenaNode* ArenaGraph::getNode(unsigned int i) const
{
assert(i < m_all_nodes.size());
ArenaNode* n = dynamic_cast<ArenaNode*>(m_all_nodes[i]);
assert(n != NULL);
return n;
} // getNode
// -----------------------------------------------------------------------------
void ArenaGraph::differentNodeColor(int n, video::SColor* c) const
{
std::set<int>::iterator it;
it = m_red_node.find(n);
if (it != m_red_node.end())
{
*c = video::SColor(255, 255, 0, 0);
return;
}
it = m_blue_node.find(n);
if (it != m_blue_node.end())
{
*c = video::SColor(255, 0, 0, 255);
return;
}
if (UserConfigParams::m_track_debug)
{
if (m_all_nodes[n]->is3DQuad())
*c = video::SColor(255, 0, 255, 0);
else
*c = video::SColor(255, 255, 255, 0);
}
} // differentNodeColor
// -----------------------------------------------------------------------------
void ArenaGraph::loadNavmesh(const std::string &navmesh)
{
XMLNode *xml = file_manager->createXMLTree(navmesh);
if (xml->getName() != "navmesh")
{
Log::error("ArenaGraph", "NavMesh is invalid.");
delete xml;
return;
}
std::vector<Vec3> all_vertices;
for (unsigned int i = 0; i < xml->getNumNodes(); i++)
{
const XMLNode *xml_node = xml->getNode(i);
if (xml_node->getName() == "vertices")
{
for (unsigned int i = 0; i < xml_node->getNumNodes(); i++)
{
const XMLNode *xml_node_node = xml_node->getNode(i);
if (!(xml_node_node->getName() == "vertex"))
{
Log::error("ArenaGraph", "Unsupported type '%s' found"
"in '%s' - ignored.",
xml_node_node->getName().c_str(), navmesh.c_str());
continue;
}
// Reading vertices
float x, y, z;
xml_node_node->get("x", &x);
xml_node_node->get("y", &y);
xml_node_node->get("z", &z);
Vec3 p(x, y, z);
all_vertices.push_back(p);
}
}
if (xml_node->getName() == "faces")
{
for (unsigned int i = 0; i < xml_node->getNumNodes(); i++)
{
const XMLNode *xml_node_node = xml_node->getNode(i);
if (xml_node_node->getName() != "face")
{
Log::error("ArenaGraph", "Unsupported type '%s'"
" found in '%s' - ignored.",
xml_node_node->getName().c_str(), navmesh.c_str());
continue;
}
// Reading quads
std::vector<int> quad_index;
std::vector<int> adjacent_quad_index;
xml_node_node->get("indices", &quad_index);
xml_node_node->get("adjacents", &adjacent_quad_index);
if (quad_index.size() != 4)
{
Log::error("ArenaGraph", "A Node in navmesh is not made"
" of quad, will only use the first 4 vertices");
}
createQuad(all_vertices[quad_index[0]],
all_vertices[quad_index[1]], all_vertices[quad_index[2]],
all_vertices[quad_index[3]], (int)m_all_nodes.size(),
false/*invisible*/, false/*ai_ignore*/, true/*is_arena*/,
false/*ignore*/);
ArenaNode* cur_node = getNode((int)m_all_nodes.size() - 1);
cur_node->setAdjacentNodes(adjacent_quad_index);
}
}
}
const XMLNode* ht = xml->getNode("height-testing");
if (ht)
{
float min = Graph::MIN_HEIGHT_TESTING;
float max = Graph::MAX_HEIGHT_TESTING;
ht->get("min", &min);
ht->get("max", &max);
for (unsigned i = 0; i < m_all_nodes.size(); i++)
{
m_all_nodes[i]->setHeightTesting(min, max);
}
}
delete xml;
} // loadNavmesh
// ----------------------------------------------------------------------------
void ArenaGraph::buildGraph()
{
const unsigned int n_nodes = getNumNodes();
m_distance_matrix = std::vector<std::vector<float>>
(n_nodes, std::vector<float>(n_nodes, 9999.9f));
for (unsigned int i = 0; i < n_nodes; i++)
{
ArenaNode* cur_node = getNode(i);
for (const int& adjacent : cur_node->getAdjacentNodes())
{
Vec3 diff = getNode(adjacent)->getCenter() - cur_node->getCenter();
float distance = diff.length();
m_distance_matrix[i][adjacent] = distance;
}
m_distance_matrix[i][i] = 0.0f;
}
// Allocate and initialise the previous node data structure:
m_parent_node = std::vector<std::vector<int16_t>>
(n_nodes, std::vector<int16_t>(n_nodes, Graph::UNKNOWN_SECTOR));
for (unsigned int i = 0; i < n_nodes; i++)
{
for (unsigned int j = 0; j < n_nodes; j++)
{
if (i == j || m_distance_matrix[i][j] >= 9899.9f)
m_parent_node[i][j] = -1;
else
m_parent_node[i][j] = i;
} // for j
} // for i
} // buildGraph
// ----------------------------------------------------------------------------
/** Dijkstra shortest path computation. It computes the shortest distance from
* the specified node 'source' to all other nodes. At the end of the
* computation, m_distance_matrix[i][j] stores the shortest path distance from
* source to j and m_parent_node[source][j] stores the last vertex visited on
* the shortest path from i to j before visiting j. Suppose the shortest path
* from i to j is i->......->k->j then m_parent_node[i][j] = k
*/
void ArenaGraph::computeDijkstra(int source)
{
// Stores the distance (float) to 'source' from a specified node (int)
typedef std::pair<int, float> IndDistPair;
class Shortest
{
public:
bool operator()(const IndDistPair &p1, const IndDistPair &p2)
{
return p1.second > p2.second;
}
};
std::priority_queue<IndDistPair, std::vector<IndDistPair>, Shortest> queue;
IndDistPair begin(source, 0.0f);
queue.push(begin);
const unsigned int n = getNumNodes();
std::vector<bool> visited;
visited.resize(n, false);
while (!queue.empty())
{
// Get element with shortest path
IndDistPair current = queue.top();
queue.pop();
int cur_index = current.first;
if (visited[cur_index]) continue;
visited[cur_index] = true;
for (const int& adjacent : getNode(cur_index)->getAdjacentNodes())
{
// Distance already computed, can be ignored
if (visited[adjacent]) continue;
float new_dist =
current.second + m_distance_matrix[cur_index][adjacent];
if (new_dist < m_distance_matrix[source][adjacent])
{
m_distance_matrix[source][adjacent] = new_dist;
m_parent_node[source][adjacent] = cur_index;
}
IndDistPair pair(adjacent, new_dist);
queue.push(pair);
}
}
} // computeDijkstra
// ----------------------------------------------------------------------------
/** THIS FUNCTION IS ONLY USED FOR UNIT-TESTING, to verify that the new
* Dijkstra algorithm gives the same results.
* computeFloydWarshall() computes the shortest distance between any two
* nodes. At the end of the computation, m_distance_matrix[i][j] stores the
* shortest path distance from i to j and m_parent_node[i][j] stores the last
* vertex visited on the shortest path from i to j before visiting j. Suppose
* the shortest path from i to j is i->......->k->j then
* m_parent_node[i][j] = k
*/
void ArenaGraph::computeFloydWarshall()
{
unsigned int n = getNumNodes();
for (unsigned int k = 0; k < n; k++)
{
for (unsigned int i = 0; i < n; i++)
{
for (unsigned int j = 0; j < n; j++)
{
if ((m_distance_matrix[i][k] + m_distance_matrix[k][j]) <
m_distance_matrix[i][j])
{
m_distance_matrix[i][j] =
m_distance_matrix[i][k] + m_distance_matrix[k][j];
m_parent_node[i][j] = m_parent_node[k][j];
}
}
}
}
} // computeFloydWarshall
// -----------------------------------------------------------------------------
void ArenaGraph::loadGoalNodes(const XMLNode *node)
{
const XMLNode *check_node = node->getNode("checks");
for (unsigned int i = 0; i < check_node->getNumNodes(); i++)
{
const XMLNode *goal = check_node->getNode(i);
if (goal->getName() =="goal")
{
Vec3 p1, p2;
bool first_goal = false;
goal->get("first_goal", &first_goal);
goal->get("p1", &p1);
goal->get("p2", &p2);
int first = Graph::UNKNOWN_SECTOR;
findRoadSector(p1, &first, NULL, true);
int last = Graph::UNKNOWN_SECTOR;
findRoadSector(p2, &last, NULL, true);
first_goal ? m_blue_node.insert(first) : m_red_node.insert(first);
first_goal ? m_blue_node.insert(last) : m_red_node.insert(last);
while (first != last)
{
// Find all the nodes which connect the two points of
// goal, notice: only work if it's a straight line
first = getNextNode(first, last);
first_goal ? m_blue_node.insert(first) :
m_red_node.insert(first);
}
}
}
} // loadGoalNodes
// ----------------------------------------------------------------------------
void ArenaGraph::setNearbyNodesOfAllNodes()
{
// Only save the nearby 8 nodes
const unsigned int try_count = 8;
for (unsigned int i = 0; i < getNumNodes(); i++)
{
// Get the distance to all nodes at i
ArenaNode* cur_node = getNode(i);
std::vector<int> nearby_nodes;
std::vector<float> dist = m_distance_matrix[i];
// Skip the same node
dist[i] = 999999.0f;
for (unsigned int j = 0; j < try_count; j++)
{
std::vector<float>::iterator it =
std::min_element(dist.begin(), dist.end());
const int pos = int(it - dist.begin());
nearby_nodes.push_back(pos);
dist[pos] = 999999.0f;
}
cur_node->setNearbyNodes(nearby_nodes);
}
} // setNearbyNodesOfAllNodes
// ----------------------------------------------------------------------------
/** Determines the full path from 'from' to 'to' and returns it in a
* std::vector (in reverse order). Used only for unit testing.
*/
std::vector<int16_t> ArenaGraph::getPathFromTo(int from, int to,
const std::vector< std::vector< int16_t > >& parent_node)
{
std::vector<int16_t> path;
path.push_back(to);
while(from!=to)
{
to = parent_node[from][to];
path.push_back(to);
}
return path;
} // getPathFromTo
// ============================================================================
/** Unit testing for arena graph distance and parent node computation.
* Instead of using hand-tuned test cases we use the tested, verified and
* easier to understand Floyd-Warshall algorithm to compute the distances,
* and check if the (significanty faster) Dijkstra algorithm gives the same
* results. For now we use the cave mesh as test case.
*/
void ArenaGraph::unitTesting()
{
Track *track = track_manager->getTrack("cave");
std::string navmesh_file_name=track->getTrackFile("navmesh.xml");
double s = StkTime::getRealTime();
ArenaGraph* ag = new ArenaGraph(navmesh_file_name);
double e = StkTime::getRealTime();
Log::error("Time", "Dijkstra %lf", e-s);
// Save the Dijkstra results
std::vector< std::vector< float > > distance_matrix = ag->m_distance_matrix;
std::vector< std::vector< int16_t > > parent_node = ag->m_parent_node;
ag->buildGraph();
// Now compute results with Floyd-Warshall
s = StkTime::getRealTime();
ag->computeFloydWarshall();
e = StkTime::getRealTime();
Log::error("Time", "Floyd-Warshall %lf", e-s);
int error_count = 0;
for(unsigned int i=0; i<ag->m_distance_matrix.size(); i++)
{
for(unsigned int j=0; j<ag->m_distance_matrix[i].size(); j++)
{
if(ag->m_distance_matrix[i][j] - distance_matrix[i][j] > 0.001f)
{
Log::error("ArenaGraph",
"Incorrect distance %d, %d: Dijkstra: %f F.W.: %f",
i, j, distance_matrix[i][j], ag->m_distance_matrix[i][j]);
error_count++;
} // if distance is too different
// Unortunately it happens frequently that there are different
// shortest path with the same length. And Dijkstra might find
// a different path then Floyd-Warshall. So the test for parent
// polygon often results in false positives, so it is disabled,
// but I leave the code in place in case it is useful for some
// debugging in the feature
#undef TEST_PARENT_POLY_EVEN_THOUGH_MANY_FALSE_POSITIVES
#ifdef TEST_PARENT_POLY_EVEN_THOUGH_MANY_FALSE_POSITIVES
if(ag->m_parent_node[i][j] != parent_node[i][j])
{
error_count++;
std::vector<int16_t> dijkstra_path = getPathFromTo(i, j, parent_node);
std::vector<int16_t> floyd_path = getPathFromTo(i, j, ag->m_parent_node);
if(dijkstra_path.size()!=floyd_path.size())
{
Log::error("ArenaGraph",
"Incorrect path length %d, %d: Dijkstra: %d F.W.: %d",
i, j, parent_node[i][j], ag->m_parent_node[i][j]);
continue;
}
Log::error("ArenaGraph", "Path problems from %d to %d:",
i, j);
for (unsigned k = 0; k < dijkstra_path.size(); k++)
{
if(dijkstra_path[k]!=floyd_path[k])
Log::error("ArenaGraph", "%d/%d dijkstra: %d floyd %d",
k, dijkstra_path.size(), dijkstra_path[k],
floyd_path[k]);
} // for k<dijkstra_path.size()
} // if dijkstra parent_node != floyd parent node
#endif
} // for j
} // for i
delete ag;
} // unitTesting