1. Epic GamesDeveloper
  3. dtCrowd

dtCrowd

Provides local steering behaviors for a group of agents.

Unreal Engine C++ API Reference > Runtime > Navmesh > DetourCrowd

References

   
Module Navmesh
Header /Engine/Source/Runtime/Navmesh/Public/DetourCrowd/DetourCrowd.h
Include #include "DetourCrowd/DetourCrowd.h"

Syntax

class dtCrowd

Remarks

Provides local steering behaviors for a group of agents.

This is the core class of the Crowd module. See the Crowd documentation for a summary of the crowd features.

A common method for setting up the crowd is as follows:

Allocate the crowd using dtAllocCrowd.

Initialize the crowd using init().

Set the avoidance configurations using setObstacleAvoidanceParams().

Add agents using addAgent() and make an initial movement request using requestMoveTarget().

A common process for managing the crowd is as follows:

Call update() to allow the crowd to manage its agents.

Retrieve agent information using getActiveAgents().

Make movement requests using requestMoveTarget() when movement goal changes.

Repeat every frame.

Some agent configuration settings can be updated using updateAgentParameters(). But the crowd owns the agent position. So it is not possible to update an active agent's position. If agent position must be fed back into the crowd, the agent must be removed and re-added.

Notes:

  • Path related information is available for newly added agents only after an update() has been performed.
  • Agent objects are kept in a pool and re-used. So it is important when using agent objects to check the value of dtCrowdAgent::active to determine if the agent is actually in use or not.
  • This class is meant to provide 'local' movement. There is a limit of 256 polygons in the path corridor. So it is not meant to provide automatic pathfinding services over long distances.

Constructors

  Type Name Description
Public function  

dtCrowd ()

  

Destructors

  Type Name Description
Public function    

Functions

  Type Name Description
Public function int

addAgent ( const dtReal* pos,
const dtCrowdAgentParams& params,
const dtQueryFilter* filter
)

 Adds a new agent to the crowd.
Public function int Cache list of active agents
Public function Const dtCrowdAgent ** Gets all cached active agents.
Public function int

getActiveAgents ( dtCrowdAgent** agents,
const int maxAgents
)

 Gets the active agents int the agent pool.
Public function const dtCrowdAgent *

getAgent ( const int idx
)

 Gets the specified agent from the pool.
Public function Const const dtCrowdAgentAnimation * Gets all agent animations.
Public function Const const int The maximum number of agents that can be managed by the object.
Public function Const int

getAgentIndex ( const dtCrowdAgent* agent
)

  
Public function dtQueryFilter *

getEditableFilter ( const int idx
)

 Gets the filter used by the crowd.
Public function Const const dtQueryFilter *

getFilter ( const int idx
)

 Gets the filter used by the crowd.
Public function Const const dtProximityGrid *

getGrid ()

 Gets the crowd's proximity grid.
Public function Const const dtNavMeshQuery * Gets the query object used by the crowd.
Public function Const int  
Public function Const const dtObstacleAvoidanceParams *

getObstacleAvoidanceParams ( const int idx
)

 Gets the shared avoidance configuration for the specified index.
Public function bool

getObstacleAvoidancePattern ( int idx,
dtReal* angles,
dtReal* radii,
int* nsamples
)

 [UE] Gets the shared avoidance sampling pattern for the specified index.
Public function Const const dtPathQueue * Gets the crowd's path request queue.
Public function Const const dtReal * Gets the search extents [(x, y, z)] used by the crowd for query operations.
Public function Const const dtSharedBoundary * Gets shared boundary cache.
Public function Const int Gets the velocity sample count.
Public function bool

init ( const int maxAgents,
const dtReal maxAgentRadius,
dtNavMesh* nav
)

 Initializes the crowd. May be called more than once to purge and re-initialize the crowd.
Public function bool

initAvoidance ( const int maxNeighbors,
const int maxWalls,
const int maxCustomPatterns
)

 [UE] Initializes the avoidance query.
Public function Const bool

isOutsideCorridor ( const int idx
)

 [UE] Check if agent moved away from its path corridor
Public function void

removeAgent ( const int idx
)

 Removes the agent from the crowd.
Public function bool

requestMoveTarget ( const int idx,
dtPolyRef ref,
const dtReal* pos
)

 Submits a new move request for the specified agent.
Public function bool

requestMoveVelocity ( const int idx,
const dtReal* vel
)

 Submits a new move request for the specified agent.
Public function bool

resetAgentVelocity ( const int idx
)

 [UE] Resets agent's velocity
Public function bool

resetMoveTarget ( const int idx
)

 Resets any request for the specified agent.
Public function bool

setAgentBackOnLink ( const int idx
)

 [UE] Switch to offmesh link state
Public function void

setAgentCheckInterval ( const dtReal t
)

 [UE] Set time between attempts to restore agents state
Public function bool

setAgentCorridor ( const int idx,
const dtPolyRef* path,
const int npath
)

 [UE] Set agent corridor, works only just after requesting move target when agent didn't start any pathfinding operations yet Use with caution!
Public function bool

setAgentWaiting ( const int idx
)

 [UE] Switch to waiting state
Public function void [UE]
Public function void

setObstacleAvoidanceParams ( const int idx,
const dtObstacleAvoidanceParams* params
)

 Sets the shared avoidance configuration for the specified index.
Public function void

setObstacleAvoidancePattern ( int idx,
const dtReal* angles,
const dtReal* radii,
int nsamples
)

 [UE] Sets the shared avoidance sampling pattern for the specified index.
Public function void

setPathOffsetRadiusMultiplier ( dtReal RadiusMultiplier
)

 [UE] Set agent radius multiplier for offseting path from corners
Public function void

setPruneStartedOffmeshConnections ( bool bRemoveFromCorridor
)

 [UE] Set offmesh connection pruning This will allow removing offmesh connection poly ref from corridor as soon as offmesh connection anim is triggered (default behavior)
Public function void

setSeparationFilter ( dtReal InFilter
)

 [UE] Set separation filter param
Public function void [UE] Set visibility optimization to use single area raycasts This will prevent from cutting through polys marked as different area which could have been avoided in corridor's path
Public function void

update ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 Updates the steering and positions of all agents.
Public function bool

updateAgentFilter ( const int idx,
const dtQueryFilter* filter
)

 [UE] Updates the specified agent's query filter.
Public function void

updateAgentParameters ( const int idx,
const dtCrowdAgentParams& params
)

 Updates the specified agent's configuration.
Public function void

updateAgentState ( const int idx,
bool repath
)

 [UE] Refresh state of agent, used after completing movement through offmesh links
Public function void

updateStepAvoidance ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: avoidance
Public function void

updateStepCorridor ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: corridor updates at new position
Public function void

updateStepMove ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: integrate velocities and handle collisions
Public function void

updateStepNextMovePoint ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: next corner for move, trigger offmesh links
Public function void

updateStepOffMeshAnim ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: offmesh anims
Public function void

updateStepOffMeshVelocity ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: offmesh link velocity (instead of playing animation)
Public function void

updateStepPaths ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: path validity, path cache and path optimizations
Public function void

updateStepProximityData ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: neighbors and boundaries
Public function void

updateStepSteering ( const dtReal dt,
dtCrowdAgentDebugInfo* debug
)

 [UE] Split update into several smaller components: steering

See Also

dtAllocCrowd()

dtFreeCrowd()

init()

dtCrowdAgent

Ask questions and help your peers Developer Forums

Write your own tutorials or read those from others Learning Library

On this page