public void GenerateNavMesh(BaseEntity terrain)
{
this.terrain = terrain;
this.terrainComp = this.terrain.GetComponentByType(ComponentType.TerrainComponent) as TerrainComponent;
// Process each pixel of the heightmap as a navmeshnode.
// Create a navmeshnode, even if the slope is too great.
int width = this.terrainComp.Size;
int widthMinusOne = width - 1;
// Find four vertexs that comprise a node
for (int x = 0; x < widthMinusOne; ++x)
{
for (int z = 0; z < widthMinusOne; ++z)
{
NavMeshNode newNode = new NavMeshNode((x + (z * width)), width);
// Grab the normal of the quad that makes up this NavMeshNode, because the terrain engine organizes triangles into
// quads, we don't need to check both triangles in the quad, as they'll have the same normal. So, any corner of the
// quad will have the same normal, we'll just take the topleft corner's normal.
newNode.Normal = this.terrainComp.normals[newNode.ZCoordTopLeft, newNode.XCoordTopLeft];
nodeDictionary.Add(newNode.VertexTopLeft, newNode);
}
}
// Postprocess step, optimize navmesh by combining navmeshnodes into navmeshchunks.
for (int x = 0; x < widthMinusOne; ++x)
{
for (int z = 0; z < widthMinusOne; ++z)
{
int topLeftVertex = x + (z * width);
// Check if there is a node at this [x, z] location, if there isn't then it has already
// been processed into a chunk
if (nodeDictionary.ContainsKey(topLeftVertex))
{
NavMeshNode node;
nodeDictionary.TryGetValue(topLeftVertex, out node);
if (node != null)
{
NavMeshChunk newChunk = new NavMeshChunk(this.parent);
ProcessNewChunk(newChunk, node);
}
else
{
throw new Exception("Failed to find a value in 'nodeDictionary'");
}
}
}
}
// Once all chunks are created, we need to go through each chunk, and create a list of connection points between chunks so we know how
// to navigate from chunk to chunk.
meshGenerated = true;
}
/// <summary>
/// Attempts to add a new row to a NavMeshChunk
/// </summary>
/// <param name="chunk">Chunk to add a new row to</param>
/// <returns>Whether or not the row was added</returns>
private bool AddNewRowToChunk(NavMeshChunk chunk)
{
// Is this chunk's max column already at the end of the map
if (chunk.GetMaxRow() == this.terrainComp.Size - 1)
{
return(false);
}
int row = chunk.GetMaxRow() + 1;
int startingColumn = chunk.GetMinColumn();
int endColumn = chunk.GetMaxColumn();
List <NavMeshNode> nodesToAdd = new List <NavMeshNode>();
for (int x = startingColumn; x <= endColumn; ++x)
{
int vertexTopLeft = x + (row * this.terrainComp.Size);
NavMeshNode node;
nodeDictionary.TryGetValue(vertexTopLeft, out node);
// Node doesn't exist (was already chunked), so we fail at getting a new column
if (node == null)
{
return(false);
}
// If node is too steep then it cannot be part of this chunk
if (node.TooSteep)
{
return(false);
}
nodesToAdd.Add(node);
}
// If we made it this far, lets add the column into the chunk
foreach (NavMeshNode node in nodesToAdd)
{
chunk.AddNode(node, true);
chunkDictionary.Add(node.VertexTopLeft, chunk);
nodeDictionary.Remove(node.VertexTopLeft);
}
return(true);
}
private void ProcessNewChunk(NavMeshChunk chunk, NavMeshNode startingNode)
{
bool columnsAvail = true;
bool rowsAvail = true;
chunk.AddNode(startingNode, true);
chunkDictionary.Add(startingNode.VertexTopLeft, chunk);
nodeDictionary.Remove(startingNode.VertexTopLeft);
if (startingNode.TooSteep)
{
return;
}
//// TEMP!!!!!!!!!!!!!!!!!!!!
//if (startingNode.VertexTopLeft == 0)
//{
// int i = 5;
// i++;
//}
while (columnsAvail || rowsAvail)
{
if (columnsAvail)
{
columnsAvail = AddNewColumnToChunk(chunk);
}
if (rowsAvail)
{
rowsAvail = AddNewRowToChunk(chunk);
}
}
// Once we've made it here, that means the current chunk cannot expand any more
}