DotRecastNetSim/src/DotRecast.Detour.Crowd/DtPathCorridor.cs

508 lines
22 KiB
C#

/*
Copyright (c) 2009-2010 Mikko Mononen memon@inside.org
recast4j copyright (c) 2015-2019 Piotr Piastucki piotr@jtilia.org
DotRecast Copyright (c) 2023 Choi Ikpil ikpil@naver.com
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
using System;
using System.Collections.Generic;
using DotRecast.Core;
using DotRecast.Core.Numerics;
namespace DotRecast.Detour.Crowd
{
/// Represents a dynamic polygon corridor used to plan agent movement.
/// @ingroup crowd, detour
public class DtPathCorridor
{
private RcVec3f m_pos;
private RcVec3f m_target;
private List<long> m_path;
private int m_maxPath;
/**
@class dtPathCorridor
@par
The corridor is loaded with a path, usually obtained from a #dtNavMeshQuery::findPath() query. The corridor
is then used to plan local movement, with the corridor automatically updating as needed to deal with inaccurate
agent locomotion.
Example of a common use case:
-# Construct the corridor object and call #init() to allocate its path buffer.
-# Obtain a path from a #dtNavMeshQuery object.
-# Use #reset() to set the agent's current position. (At the beginning of the path.)
-# Use #setCorridor() to load the path and target.
-# Use #findCorners() to plan movement. (This handles dynamic path straightening.)
-# Use #movePosition() to feed agent movement back into the corridor. (The corridor will automatically adjust as needed.)
-# If the target is moving, use #moveTargetPosition() to update the end of the corridor.
(The corridor will automatically adjust as needed.)
-# Repeat the previous 3 steps to continue to move the agent.
The corridor position and target are always constrained to the navigation mesh.
One of the difficulties in maintaining a path is that floating point errors, locomotion inaccuracies, and/or local
steering can result in the agent crossing the boundary of the path corridor, temporarily invalidating the path.
This class uses local mesh queries to detect and update the corridor as needed to handle these types of issues.
The fact that local mesh queries are used to move the position and target locations results in two beahviors that
need to be considered:
Every time a move function is used there is a chance that the path will become non-optimial. Basically, the further
the target is moved from its original location, and the further the position is moved outside the original corridor,
the more likely the path will become non-optimal. This issue can be addressed by periodically running the
#optimizePathTopology() and #optimizePathVisibility() methods.
All local mesh queries have distance limitations. (Review the #dtNavMeshQuery methods for details.) So the most accurate
use case is to move the position and target in small increments. If a large increment is used, then the corridor
may not be able to accurately find the new location. Because of this limiation, if a position is moved in a large
increment, then compare the desired and resulting polygon references. If the two do not match, then path replanning
may be needed. E.g. If you move the target, check #getLastPoly() to see if it is the expected polygon.
*/
public DtPathCorridor()
{
}
/// @par
///
/// @warning Cannot be called more than once.
/// Allocates the corridor's path buffer.
/// @param[in] maxPath The maximum path size the corridor can handle.
/// @return True if the initialization succeeded.
public bool Init(int maxPath)
{
m_path = new List<long>();
m_maxPath = maxPath;
return true;
}
/// @par
///
/// Essentially, the corridor is set of one polygon in size with the target
/// equal to the position.
///
/// Resets the path corridor to the specified position.
/// @param[in] ref The polygon reference containing the position.
/// @param[in] pos The new position in the corridor. [(x, y, z)]
public void Reset(long refs, RcVec3f pos)
{
m_pos = pos;
m_target = pos;
m_path.Clear();
m_path.Add(refs);
}
/**
@par
This is the function used to plan local movement within the corridor. One or more corners can be
detected in order to plan movement. It performs essentially the same function as #dtNavMeshQuery::findStraightPath.
Due to internal optimizations, the maximum number of corners returned will be (@p maxCorners - 1)
For example: If the buffers are sized to hold 10 corners, the function will never return more than 9 corners.
So if 10 corners are needed, the buffers should be sized for 11 corners.
If the target is within range, it will be the last corner and have a polygon reference id of zero.
*/
/// Finds the corners in the corridor from the position toward the target. (The straightened path.)
/// @param[out] cornerVerts The corner vertices. [(x, y, z) * cornerCount] [Size: <= maxCorners]
/// @param[out] cornerFlags The flag for each corner. [(flag) * cornerCount] [Size: <= maxCorners]
/// @param[out] cornerPolys The polygon reference for each corner. [(polyRef) * cornerCount]
/// [Size: <= @p maxCorners]
/// @param[in] maxCorners The maximum number of corners the buffers can hold.
/// @param[in] navquery The query object used to build the corridor.
/// @param[in] filter The filter to apply to the operation.
/// @return The number of corners returned in the corner buffers. [0 <= value <= @p maxCorners]
public int FindCorners(ref List<DtStraightPath> corners, int maxCorners, DtNavMeshQuery navquery, IDtQueryFilter filter)
{
const float MIN_TARGET_DIST = 0.01f;
var result = navquery.FindStraightPath(m_pos, m_target, m_path, ref corners, maxCorners, 0);
if (result.Succeeded())
{
// Prune points in the beginning of the path which are too close.
int start = 0;
foreach (DtStraightPath spi in corners)
{
if ((spi.flags & DtStraightPathFlags.DT_STRAIGHTPATH_OFFMESH_CONNECTION) != 0
|| RcVecUtils.Dist2DSqr(spi.pos, m_pos) > RcMath.Sqr(MIN_TARGET_DIST))
{
break;
}
start++;
}
int end = corners.Count;
// Prune points after an off-mesh connection.
for (int i = start; i < corners.Count; i++)
{
DtStraightPath spi = corners[i];
if ((spi.flags & DtStraightPathFlags.DT_STRAIGHTPATH_OFFMESH_CONNECTION) != 0)
{
end = i + 1;
break;
}
}
corners = corners.GetRange(start, end - start);
}
return corners.Count;
}
/**
@par
Inaccurate locomotion or dynamic obstacle avoidance can force the argent position significantly outside the
original corridor. Over time this can result in the formation of a non-optimal corridor. Non-optimal paths can
also form near the corners of tiles.
This function uses an efficient local visibility search to try to optimize the corridor
between the current position and @p next.
The corridor will change only if @p next is visible from the current position and moving directly toward the point
is better than following the existing path.
The more inaccurate the agent movement, the more beneficial this function becomes. Simply adjust the frequency
of the call to match the needs to the agent.
This function is not suitable for long distance searches.
*/
/// Attempts to optimize the path if the specified point is visible from the current position.
/// @param[in] next The point to search toward. [(x, y, z])
/// @param[in] pathOptimizationRange The maximum range to search. [Limit: > 0]
/// @param[in] navquery The query object used to build the corridor.
/// @param[in] filter The filter to apply to the operation.
public void OptimizePathVisibility(RcVec3f next, float pathOptimizationRange, DtNavMeshQuery navquery, IDtQueryFilter filter)
{
// Clamp the ray to max distance.
float dist = RcVecUtils.Dist2D(m_pos, next);
// If too close to the goal, do not try to optimize.
if (dist < 0.01f)
{
return;
}
// Overshoot a little. This helps to optimize open fields in tiled meshes.
dist = Math.Min(dist + 0.01f, pathOptimizationRange);
// Adjust ray length.
var delta = RcVec3f.Subtract(next, m_pos);
RcVec3f goal = RcVecUtils.Mad(m_pos, delta, pathOptimizationRange / dist);
var res = new List<long>();
var status = navquery.Raycast(m_path[0], m_pos, goal, filter, out var t, out var norm, ref res);
if (status.Succeeded())
{
if (res.Count > 1 && t > 0.99f)
{
m_path = DtPathUtils.MergeCorridorStartShortcut(m_path, m_path.Count, m_maxPath, res);
}
}
}
/**
@par
Inaccurate locomotion or dynamic obstacle avoidance can force the agent position significantly outside the
original corridor. Over time this can result in the formation of a non-optimal corridor. This function will use a
local area path search to try to re-optimize the corridor.
The more inaccurate the agent movement, the more beneficial this function becomes. Simply adjust the frequency of
the call to match the needs to the agent.
*/
/// Attempts to optimize the path using a local area search. (Partial replanning.)
/// @param[in] navquery The query object used to build the corridor.
/// @param[in] filter The filter to apply to the operation.
public bool OptimizePathTopology(DtNavMeshQuery navquery, IDtQueryFilter filter, int maxIterations)
{
if (m_path.Count < 3)
{
return false;
}
var res = new List<long>();
navquery.InitSlicedFindPath(m_path[0], m_path[^1], m_pos, m_target, filter, 0);
navquery.UpdateSlicedFindPath(maxIterations, out var _);
var status = navquery.FinalizeSlicedFindPathPartial(m_path, ref res);
if (status.Succeeded() && res.Count > 0)
{
m_path = DtPathUtils.MergeCorridorStartShortcut(m_path, m_path.Count, m_maxPath, res);
return true;
}
return false;
}
public bool MoveOverOffmeshConnection(long offMeshConRef, long[] refs, ref RcVec3f startPos, ref RcVec3f endPos, DtNavMeshQuery navquery)
{
// Advance the path up to and over the off-mesh connection.
long prevRef = 0, polyRef = m_path[0];
int npos = 0;
while (npos < m_path.Count && polyRef != offMeshConRef)
{
prevRef = polyRef;
polyRef = m_path[npos];
npos++;
}
if (npos == m_path.Count)
{
// Could not find offMeshConRef
return false;
}
// Prune path
m_path = m_path.GetRange(npos, m_path.Count - npos);
refs[0] = prevRef;
refs[1] = polyRef;
DtNavMesh nav = navquery.GetAttachedNavMesh();
var startEnd = nav.GetOffMeshConnectionPolyEndPoints(refs[0], refs[1], ref startPos, ref endPos);
if (startEnd.Succeeded())
{
m_pos = endPos;
return true;
}
return false;
}
/**
@par
Behavior:
- The movement is constrained to the surface of the navigation mesh.
- The corridor is automatically adjusted (shorted or lengthened) in order to remain valid.
- The new position will be located in the adjusted corridor's first polygon.
The expected use case is that the desired position will be 'near' the current corridor. What is considered 'near'
depends on local polygon density, query search half extents, etc.
The resulting position will differ from the desired position if the desired position is not on the navigation mesh,
or it can't be reached using a local search.
*/
/// Moves the position from the current location to the desired location, adjusting the corridor
/// as needed to reflect the change.
/// @param[in] npos The desired new position. [(x, y, z)]
/// @param[in] navquery The query object used to build the corridor.
/// @param[in] filter The filter to apply to the operation.
/// @return Returns true if move succeeded.
public bool MovePosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFilter filter)
{
// Move along navmesh and update new position.
var visited = new List<long>();
var status = navquery.MoveAlongSurface(m_path[0], m_pos, npos, filter, out var result, ref visited);
if (status.Succeeded())
{
m_path = DtPathUtils.MergeCorridorStartMoved(m_path, m_path.Count, m_maxPath, visited);
// Adjust the position to stay on top of the navmesh.
m_pos = result;
status = navquery.GetPolyHeight(m_path[0], result, out var h);
if (status.Succeeded())
{
m_pos.Y = h;
}
return true;
}
return false;
}
/**
@par
Behavior:
- The movement is constrained to the surface of the navigation mesh.
- The corridor is automatically adjusted (shorted or lengthened) in order to remain valid.
- The new target will be located in the adjusted corridor's last polygon.
The expected use case is that the desired target will be 'near' the current corridor. What is considered 'near' depends on local polygon density, query search half extents, etc.
The resulting target will differ from the desired target if the desired target is not on the navigation mesh, or it can't be reached using a local search.
*/
/// Moves the target from the curent location to the desired location, adjusting the corridor
/// as needed to reflect the change.
/// @param[in] npos The desired new target position. [(x, y, z)]
/// @param[in] navquery The query object used to build the corridor.
/// @param[in] filter The filter to apply to the operation.
/// @return Returns true if move succeeded.
public bool MoveTargetPosition(RcVec3f npos, DtNavMeshQuery navquery, IDtQueryFilter filter)
{
// Move along navmesh and update new position.
var visited = new List<long>();
var status = navquery.MoveAlongSurface(m_path[^1], m_target, npos, filter, out var result, ref visited);
if (status.Succeeded())
{
m_path = DtPathUtils.MergeCorridorEndMoved(m_path, m_path.Count, m_maxPath, visited);
// TODO: should we do that?
// Adjust the position to stay on top of the navmesh.
/*
* float h = m_target.y; navquery->GetPolyHeight(m_path[m_npath-1],
* result, &h); result.y = h;
*/
m_target = result;
return true;
}
return false;
}
/// @par
///
/// The current corridor position is expected to be within the first polygon in the path. The target
/// is expected to be in the last polygon.
///
/// @warning The size of the path must not exceed the size of corridor's path buffer set during #init().
/// Loads a new path and target into the corridor.
/// @param[in] target The target location within the last polygon of the path. [(x, y, z)]
/// @param[in] path The path corridor. [(polyRef) * @p npolys]
/// @param[in] npath The number of polygons in the path.
public void SetCorridor(RcVec3f target, List<long> path)
{
m_target = target;
m_path = new List<long>(path);
}
public void FixPathStart(long safeRef, RcVec3f safePos)
{
m_pos = safePos;
if (m_path.Count < 3 && m_path.Count > 0)
{
long p = m_path[m_path.Count - 1];
m_path.Clear();
m_path.Add(safeRef);
m_path.Add(0L);
m_path.Add(p);
}
else
{
m_path.Clear();
m_path.Add(safeRef);
m_path.Add(0L);
}
}
public bool TrimInvalidPath(long safeRef, float[] safePos, DtNavMeshQuery navquery, IDtQueryFilter filter)
{
// Keep valid path as far as possible.
int n = 0;
while (n < m_path.Count && navquery.IsValidPolyRef(m_path[n], filter))
{
n++;
}
if (m_path.Count == n)
{
// All valid, no need to fix.
return true;
}
else if (n == 0)
{
// The first polyref is bad, use current safe values.
m_pos = RcVecUtils.Create(safePos);
m_path.Clear();
m_path.Add(safeRef);
}
else if (n < m_path.Count)
{
// The path is partially usable.
m_path = m_path.GetRange(0, n);
}
// Clamp target pos to last poly
navquery.ClosestPointOnPolyBoundary(m_path[m_path.Count - 1], m_target, out m_target);
return true;
}
/// @par
///
/// The path can be invalidated if there are structural changes to the underlying navigation mesh, or the state of
/// a polygon within the path changes resulting in it being filtered out. (E.g. An exclusion or inclusion flag changes.)
/// Checks the current corridor path to see if its polygon references remain valid.
///
/// @param[in] maxLookAhead The number of polygons from the beginning of the corridor to search.
/// @param[in] navquery The query object used to build the corridor.
/// @param[in] filter The filter to apply to the operation.
public bool IsValid(int maxLookAhead, DtNavMeshQuery navquery, IDtQueryFilter filter)
{
// Check that all polygons still pass query filter.
int n = Math.Min(m_path.Count, maxLookAhead);
for (int i = 0; i < n; ++i)
{
if (!navquery.IsValidPolyRef(m_path[i], filter))
{
return false;
}
}
return true;
}
/// Gets the current position within the corridor. (In the first polygon.)
/// @return The current position within the corridor.
public RcVec3f GetPos()
{
return m_pos;
}
/// Gets the current target within the corridor. (In the last polygon.)
/// @return The current target within the corridor.
public RcVec3f GetTarget()
{
return m_target;
}
/// The polygon reference id of the first polygon in the corridor, the polygon containing the position.
/// @return The polygon reference id of the first polygon in the corridor. (Or zero if there is no path.)
public long GetFirstPoly()
{
return 0 == m_path.Count ? 0 : m_path[0];
}
/// The polygon reference id of the last polygon in the corridor, the polygon containing the target.
/// @return The polygon reference id of the last polygon in the corridor. (Or zero if there is no path.)
public long GetLastPoly()
{
return 0 == m_path.Count ? 0 : m_path[m_path.Count - 1];
}
/// The corridor's path.
/// @return The corridor's path. [(polyRef) * #getPathCount()]
public List<long> GetPath()
{
return m_path;
}
/// The number of polygons in the current corridor path.
/// @return The number of polygons in the current corridor path.
public int GetPathCount()
{
return m_path.Count;
}
}
}