public void Update(double elapsedTime)
{
_selectedPolygon = _navMesh.FindNearestPolygon(_input.Mouse.Position);
_selectedVertexIndex = FindSelectedVertex(_input.Mouse.Position, _selectedPolygon, VertexEditRadius);
if (_draggingVertex)
{
if (_input.Mouse.LeftHeld && _selectedVertexIndex != -1)
{
_selectedPolygon.TryToUpdateVertPosition(_selectedVertexIndex, _input.Mouse.Position);
return;
}
else
{
_draggingVertex = false;
}
}
if (_input.Keyboard.IsKeyPressed(System.Windows.Forms.Keys.A))
{
_navMesh.AddPolygon(new ConvexPolygon(_input.Mouse.Position));
}
if (_input.Mouse.LeftHeld && _selectedVertexIndex != -1)
{
_draggingVertex = true;
}
}
public PolygonLink(ConvexPolygon startPoly, IndexedEdge startEdge, ConvexPolygon endPoly, IndexedEdge endEdge)
{
StartPoly = startPoly;
StartEdgeIndex = startEdge;
EndPoly = endPoly;
EndEdgeIndex = endEdge;
}
public PolygonLink(ConvexPolygon startPoly, IndexedEdge startEdge, ConvexPolygon endPoly, IndexedEdge endEdge)
{
StartPoly = startPoly;
StartEdgeIndex = startEdge;
EndPoly = endPoly;
EndEdgeIndex = endEdge;
}
/// <summary>
/// Works out a graph of nodes on top of the navmesh.
/// Each polygon is a node and a node is added a connecting edges of linked polygons.
/// The node graph class member is filled in by running this method.
/// It's quite likely this code isn't very optimal.
/// </summary>
/// <param name="polyStart">The polygon the entity is currently in.</param>
/// <param name="polyEnd">The polygon the entity would like to be in.</param>
/// <param name="from">The point in the entity is current positioned.</param>
/// <param name="to">The point the entity would like to be positioned.</param>
/// <param name="navMesh">The navigation mesh describing the polygons and their links.</param>
/// <returns>The start and end nodes for the journey the player wants to take</returns>
private Tuple <NavigationNode, NavigationNode> CreateNodeNetwork(ConvexPolygon polyStart, ConvexPolygon polyEnd, Point from, Point to, NavMesh navMesh)
{
_nodeGraph.Clear();
// Store a map poly -> node to make it simple to work out the connection nodes.
Dictionary <ConvexPolygon, NavigationNode> polyToNodeMap = new Dictionary <ConvexPolygon, NavigationNode>();
NavigationNode startNode = null;
NavigationNode endNode = null;
// Create a node for the centroid of each polygon
// Replace the postion of the start and end polygon.
foreach (ConvexPolygon polygon in navMesh.PolygonList)
{
Point position;
NavigationNode node;
if (polyStart == polygon)
{
position = from;
node = new NavigationNode(position);
startNode = node;
}
else if (polyEnd == polygon)
{
position = to;
node = new NavigationNode(position);
endNode = node;
}
else
{
position = polygon.CalculateCentroid();
node = new NavigationNode(position);
}
_nodeGraph.Add(node);
polyToNodeMap.Add(polygon, node);
}
// Create the edge nodes and add the links
// !* This is where you'd add several nodes per edge, if you wanted.
foreach (PolygonLink link in navMesh.Links)
{
LineSegment line = link.GetShortestEdge();
Point midPoint = line.GetMiddle();
NavigationNode connectionNode = new NavigationNode(midPoint);
// Add bidirectional links to connected polys and edge polys.
polyToNodeMap[link.StartPoly].Neighbours.Add(connectionNode);
connectionNode.Neighbours.Add(polyToNodeMap[link.StartPoly]);
polyToNodeMap[link.EndPoly].Neighbours.Add(connectionNode);
connectionNode.Neighbours.Add(polyToNodeMap[link.EndPoly]);
_nodeGraph.Add(connectionNode);
}
return(new Tuple <NavigationNode, NavigationNode>(startNode, endNode));
}
/// <summary>
/// Works out a graph of nodes on top of the navmesh.
/// Each polygon is a node and a node is added a connecting edges of linked polygons.
/// The node graph class member is filled in by running this method.
/// It's quite likely this code isn't very optimal.
/// </summary>
/// <param name="polyStart">The polygon the entity is currently in.</param>
/// <param name="polyEnd">The polygon the entity would like to be in.</param>
/// <param name="from">The point in the entity is current positioned.</param>
/// <param name="to">The point the entity would like to be positioned.</param>
/// <param name="navMesh">The navigation mesh describing the polygons and their links.</param>
/// <returns>The start and end nodes for the journey the player wants to take</returns>
private Tuple<NavigationNode, NavigationNode> CreateNodeNetwork(ConvexPolygon polyStart, ConvexPolygon polyEnd, Point from, Point to, NavMesh navMesh)
{
_nodeGraph.Clear();
// Store a map poly -> node to make it simple to work out the connection nodes.
Dictionary<ConvexPolygon, NavigationNode> polyToNodeMap = new Dictionary<ConvexPolygon, NavigationNode>();
NavigationNode startNode = null;
NavigationNode endNode = null;
// Create a node for the centroid of each polygon
// Replace the postion of the start and end polygon.
foreach (ConvexPolygon polygon in navMesh.PolygonList)
{
Point position;
NavigationNode node;
if (polyStart == polygon)
{
position = from;
node = new NavigationNode(position);
startNode = node;
}
else if (polyEnd == polygon)
{
position = to;
node = new NavigationNode(position);
endNode = node;
}
else
{
position = polygon.CalculateCentroid();
node = new NavigationNode(position);
}
_nodeGraph.Add(node);
polyToNodeMap.Add(polygon, node);
}
// Create the edge nodes and add the links
// !* This is where you'd add several nodes per edge, if you wanted.
foreach (PolygonLink link in navMesh.Links)
{
LineSegment line = link.GetShortestEdge();
Point midPoint = line.GetMiddle();
NavigationNode connectionNode = new NavigationNode(midPoint);
// Add bidirectional links to connected polys and edge polys.
polyToNodeMap[link.StartPoly].Neighbours.Add(connectionNode);
connectionNode.Neighbours.Add(polyToNodeMap[link.StartPoly]);
polyToNodeMap[link.EndPoly].Neighbours.Add(connectionNode);
connectionNode.Neighbours.Add(polyToNodeMap[link.EndPoly]);
_nodeGraph.Add(connectionNode);
}
return new Tuple<NavigationNode, NavigationNode>(startNode, endNode);
}
public void Update(double elapsedTime)
{
_selectedPolygon = _navMesh.FindNearestPolygon(_input.Mouse.Position);
if (_input.Mouse.LeftPressed)
{
if (_selectedPolygon != null)
{
_selectedPolygon.TryToAddVertex(_input.Mouse.Position);
}
}
}
public ConvexPolygon FindNearestPolygon(Point mousePos)
{
ConvexPolygon nearestPolygon = null;
float minDistance = float.MaxValue;
foreach (ConvexPolygon poly in _polygonList)
{
float distance = poly.GetClosestEdgeDistance(mousePos);
if (distance < minDistance)
{
minDistance = distance;
nearestPolygon = poly;
}
}
return(nearestPolygon);
}
/// <summary>
/// Checks all the vertices of a polygon and against a point.
/// If that point is within the radius of a vertex, then the index to that vertex is returned.
/// Otherwise -1 is returned.
/// </summary>
/// <param name="radius">The radius the position must come within for a vertex to be selected.</param>
/// <param name="position">The poisition to check against the vertices</param>
/// <param name="polygon">The polygon which will have it's vertices checked. A null polygon will return -1</param>
/// <returns>Index to vertex in the radius of the position or minus one if no suitable vertex can be found.</returns>
private int FindSelectedVertex(Point position, ConvexPolygon polygon, int radius)
{
if (polygon == null)
{
return -1;
}
for (int i = 0; i < polygon.Vertices.Count; i++)
{
Circle circle = new Circle(polygon.Vertices[i].X, polygon.Vertices[i].Y, radius);
if (circle.Intersects(position))
{
return i;
}
}
return -1;
}
public List <Point> GetPath(Point from, Point to, NavMesh navMesh)
{
List <Point> path = new List <Point>();
// First find the polygon they're in
// !* May want a little overlapping so all screen can be clicked.
// In that case this should check if all intersected options contain as same poly start/end
ConvexPolygon polyStart = navMesh.PolygonList.First(x => x.Intersects(from));
ConvexPolygon polyEnd = navMesh.PolygonList.First(x => x.Intersects(to));
if (polyStart == null || polyEnd == null)
{
return(path);
}
else if (polyStart == polyEnd)
{
path.Add(from);
path.Add(to);
}
else if (polyStart != polyEnd)
{
// This does not need doing every time but it's easier to code if is recreated.
_astar = new AStar <NavigationNode>(
delegate(NavigationNode startNode, NavigationNode endNode)
{
return(Math.Sqrt(startNode.Position.X * endNode.Position.X
+ startNode.Position.Y * endNode.Position.Y));
});
var startEndNodes = CreateNodeNetwork(polyStart, polyEnd, from, to, navMesh);
_astar.FindPath(startEndNodes.Item1, startEndNodes.Item2);
_astar.Path.Reverse();
foreach (var node in _astar.Path)
{
path.Add(node.Position);
}
}
return(path);
}
private static int FindPolygonIndex(NavMesh navMesh, ConvexPolygon convexPolygon)
{
return navMesh.PolygonList.FindIndex(convexPolygon.Equals);
}
private static void LoadSinglePolygon(XmlTextReader xmlReader, NavMesh navMesh)
{
ConvexPolygon polygon = new ConvexPolygon();
xmlReader.MoveToContent();
while (xmlReader.Read())
{
if ("point" == xmlReader.Name)
{
float x = float.Parse(xmlReader.GetAttribute("x"));
float y = float.Parse(xmlReader.GetAttribute("y"));
polygon.Vertices.Add(new Point(x, y));
}
else if("polygon" == xmlReader.Name)
{
polygon.GenerateEdges();
navMesh.AddPolygon(polygon);
return;
}
}
}
public void AddPolygon(ConvexPolygon polygon)
{
_polygonList.Add(polygon);
}
public PolygonEdgePair(ConvexPolygon polygon, IndexedEdge edge)
{
Polygon = polygon;
Edge = edge;
}
public void AddPolygon(ConvexPolygon polygon)
{
_polygonList.Add(polygon);
}
