A* Pathfinding Project  4.0.7 The A* Pathfinding Project for Unity 3D
Agent.VO Struct Reference

Velocity Obstacle. More...

## Detailed Description

Velocity Obstacle.

This is a struct to avoid too many allocations.

https://en.wikipedia.org/wiki/Velocity_obstacle

## Public Member Functions

VO (Vector2 center, Vector2 offset, float radius, float inverseDt, float inverseDeltaTime)
Creates a VO for avoiding another agent.

Vector2 Gradient (Vector2 p, out float weight)
Gradient and value of the cost function of this VO.

Vector2 ScaledGradient (Vector2 p, out float weight)
Gradient and value of the cost function of this VO.

## Static Public Member Functions

static Vector2 ComplexMultiply (Vector2 a, Vector2 b)
Complex number multiplication.

static VO SegmentObstacle (Vector2 segmentStart, Vector2 segmentEnd, Vector2 offset, float radius, float inverseDt, float inverseDeltaTime)
Creates a VO for avoiding another agent.

static float SignedDistanceFromLine (Vector2 a, Vector2 dir, Vector2 p)
Returns a negative number of if p lies on the left side of a line which with one point in a and has a tangent in the direction of dir.

## Public Attributes

Vector2 circleCenter

bool colliding

Vector2 cutoffDir

Vector2 cutoffLine

Vector2 dir1

Vector2 dir2

Vector2 line1

Vector2 line2

bool segment

Vector2 segmentEnd

Vector2 segmentStart

float weightBonus

float weightFactor

## Constructor & Destructor Documentation

 VO ( Vector2 center, Vector2 offset, float radius, float inverseDt, float inverseDeltaTime )

Creates a VO for avoiding another agent.

Parameters
 center The position of the other agent relative to this agent. offset Offset of the velocity obstacle. For example to account for the agents' relative velocities. radius Combined radius of the two agents (radius1 + radius2). inverseDt 1 divided by the local avoidance time horizon (e.g avoid agents that we will hit within the next 2 seconds). inverseDeltaTime 1 divided by the time step length.

## Member Function Documentation

 static Vector2 ComplexMultiply ( Vector2 a, Vector2 b )
static

Complex number multiplication.

Used to rotate vectors in an efficient way.

https://en.wikipedia.org/wiki/Complex_number#Multiplication_and_division
 Vector2 Gradient ( Vector2 p, out float weight )

Gradient and value of the cost function of this VO.

The VO has a cost function which is 0 outside the VO and increases inside it as the point moves further into the VO.

This is the negative gradient of that function as well as its value (the weight). The negative gradient points in the direction where the function decreases the fastest.

The value of the function is the distance to the closest edge of the VO and the gradient is normalized.

 Vector2 ScaledGradient ( Vector2 p, out float weight )

Gradient and value of the cost function of this VO.

Very similar to the Gradient method however the gradient and value have been scaled and tweaked slightly.

 static VO SegmentObstacle ( Vector2 segmentStart, Vector2 segmentEnd, Vector2 offset, float radius, float inverseDt, float inverseDeltaTime )
static

Creates a VO for avoiding another agent.

Note that the segment is directed, the agent will want to be on the left side of the segment.

 static float SignedDistanceFromLine ( Vector2 a, Vector2 dir, Vector2 p )
static

Returns a negative number of if p lies on the left side of a line which with one point in a and has a tangent in the direction of dir.

The number can be seen as the double signed area of the triangle {a, a+dir, p} multiplied by the length of dir. If dir.magnitude=1 this is also the distance from p to the line {a, a+dir}.

## Member Data Documentation

 Vector2 circleCenter
 bool colliding
 Vector2 cutoffDir
 Vector2 cutoffLine
 Vector2 dir1
 Vector2 dir2
 Vector2 line1
 Vector2 line2