GraphHitInfo.tangent is always same

General Grid graph
#1

Hi,
I use GridGraph.Linecast method to check if the unit’s moved is hit obstacled grid, then I get the GraphHitInfo. I found whatever degree by moved, the hit.tangent always return (0,0,-1) ( unit is one the side right, obstacle is on the side left) ?

GraphHitInfo hit;
var obstruct = AstarPath.active.data.gridGraph.Linecast ( GoComponent.LogicPosition, nextPos, null,
                                                          out hit );

if ( obstruct )
{
    Vector2d hitp = hit.point;

    Vector2d vector = hit.tangent;
    int degree = (int) ( Math.Atan2 ( vector.y, vector.x ) * Mathf.Rad2Deg );
    CLog.Debug ( $"degress:{degree}" );  // always = -90
    speedVector = Singleton<GameInput>.Instance.GetDegreeVector ( degree );
    dist = speedVector * FixedMath.Create ( Speed ) * deltaSecond;
    nextPos = GoComponent.LogicPosition + dist;
    GoComponent.LogicPosition = nextPos;
}
#2

Hi

Could you show a screenshot of this?

I’m not quite sure if you think the tangent is what it actually is. See the image in the documentation for a reference: https://arongranberg.com/astar/docs/graphhitinfo.html#tangent

#3

111
111833×602 14.7 KB

If start and end position is from left top to right bottom, is the tangent will change to opposite direction?

#4

Hi

No, it will not change (or rather, the direction is unspecified). However you can use a simple dot product to check if it faces the ‘right’ direction for your use case.

#5

Ok, I get it. Thanks very much!