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using UnityEngine;
using System.Collections.Generic;
using Pathfinding;
using System.Linq;
namespace Pathfinding.Examples.RTS {
[HelpURL("https://arongranberg.com/astar/documentation/stable/rtsbuildingmanager.html")]
public class RTSBuildingManager : MonoBehaviour {
public static bool IsValidBuildingPlacement (GameObject building) {
var onNavmesh = AstarPath.active.data.recastGraph.PointOnNavmesh(building.transform.position, NNConstraint.None);
// Check if the center of the building is on the navmesh
if (onNavmesh == null) return false;
var cuts = building.GetComponentsInChildren<NavmeshCut>(true);
if (cuts.Length == 0) return true;
var graph = AstarPath.active.data.recastGraph;
var characterRadius = graph.characterRadius;
var boundingBox = cuts[0].GetBounds(graph.transform, characterRadius);
List<NavmeshCut.Contour> contours = new List<NavmeshCut.Contour>();
for (int i = 0; i < cuts.Length; i++) {
boundingBox = RectUnion(boundingBox, cuts[i].GetBounds(graph.transform, characterRadius));
cuts[i].GetContour(contours, Matrix4x4.identity, characterRadius);
}
Vector2[][] contourArrays = contours.Select(c => c.contour.ToArray()).ToArray();
// Loop over all tiles in the vincinity of the building
var touchingTiles = graph.GetTouchingTilesInGraphSpace(boundingBox);
for (int x = touchingTiles.xmin; x <= touchingTiles.xmax; x++) {
for (int z = touchingTiles.ymin; z <= touchingTiles.ymax; z++) {
// Loop over all nodes in the tile
var tile = graph.GetTile(x, z);
for (int i = 0; i < tile.nodes.Length; i++) {
// Figure out which sides of the node are shared with adjacent nodes
// and which ones are graph borders.
var node = tile.nodes[i];
var usedSides = new bool[3];
for (int j = 0; j < node.connections.Length; j++) {
var conn = node.connections[j];
if (conn.isEdgeShared && conn.shapeEdge >= 0 && conn.shapeEdge < 3) usedSides[conn.shapeEdge] = true;
}
for (int j = 0; j < 3; j++) {
if (!usedSides[j]) {
// This is a graph border as it is not shared with any neighbour nodes.
// Check if this segment intersects with any navmesh cuts of the building
var segmentStart = (Vector3)node.GetVertex(j);
var segmentEnd = (Vector3)node.GetVertex((j+1) % 3);
for (int k = 0; k < contourArrays.Length; k++) {
if (Polygon.ContainsPoint(contourArrays[k], new Vector2(segmentStart.x, segmentStart.z)) || Polygon.ContainsPoint(contourArrays[k], new Vector2(segmentEnd.x, segmentEnd.z))) {
// One of the vertices of the segment was inside a navmesh cut! This means the building placement is invalid
return false;
}
var contour = contourArrays[k];
for (int v = 0; v < contour.Length; v++) {
var a = new Vector3(contour[v].x, 0.0f, contour[v].y);
var b = new Vector3(contour[(v+1) % contour.Length].x, 0.0f, contour[(v+1) % contour.Length].y);
if (VectorMath.SegmentsIntersectXZ(a, b, segmentStart, segmentEnd)) {
// This segment intersects one of the segments of a navmesh cut! This means the building placement is invalid
return false;
}
}
}
}
}
}
}
}
return true;
}
static Rect RectUnion (Rect a, Rect b) {
return Rect.MinMaxRect(Mathf.Min(a.xMin, b.xMin), Mathf.Min(a.yMin, b.yMin), Mathf.Max(a.xMax, b.xMax), Mathf.Max(a.yMax, b.yMax));
}
}
}
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