C#•10mo ago

Hey guys, how can i check if my 2 Quaternions looking in the same direction?

7 Replies

SpReeD•10mo ago

public static Quaternion LookAt(Vector3 sourcePoint, Vector3 destPoint)
{
    Vector3 forwardVector = Vector3.Normalize(destPoint - sourcePoint);

    float dot = Vector3.Dot(Vector3.forward, forwardVector);

    if (Math.Abs(dot - (-1.0f)) < 0.000001f)
    {
        return new Quaternion(Vector3.up.x, Vector3.up.y, Vector3.up.z, 3.1415926535897932f);
    }
    if (Math.Abs(dot - (1.0f)) < 0.000001f)
    {
        return Quaternion.identity;
    }

    float rotAngle = (float)Math.Acos(dot);
    Vector3 rotAxis = Vector3.Cross(Vector3.forward, forwardVector);
    rotAxis = Vector3.Normalize(rotAxis);
    return CreateFromAxisAngle(rotAxis, rotAngle);
}

public static Quaternion LookAt(Vector3 sourcePoint, Vector3 destPoint)
{
    Vector3 forwardVector = Vector3.Normalize(destPoint - sourcePoint);

    float dot = Vector3.Dot(Vector3.forward, forwardVector);

    if (Math.Abs(dot - (-1.0f)) < 0.000001f)
    {
        return new Quaternion(Vector3.up.x, Vector3.up.y, Vector3.up.z, 3.1415926535897932f);
    }
    if (Math.Abs(dot - (1.0f)) < 0.000001f)
    {
        return Quaternion.identity;
    }

    float rotAngle = (float)Math.Acos(dot);
    Vector3 rotAxis = Vector3.Cross(Vector3.forward, forwardVector);
    rotAxis = Vector3.Normalize(rotAxis);
    return CreateFromAxisAngle(rotAxis, rotAngle);
}

MrScautHDOP•10mo ago

thx! oh but i mean to check if a Quaternion look in the same direction as another one that is creating a new one

SpReeD•10mo ago

For details, check https://gamedev.stackexchange.com/questions/15070/orienting-a-model-to-face-a-target

Game Development Stack Exchange

Orienting a model to face a target

I have two objects (target and player), both have Position (Vector3) and Rotation (Quaternion). I want the target to rotate and be facing right at the player. The target, when it shoots something

bighugemassive3•10mo ago

You could convert both to euler angles then do an equality check on those 2 vectors?

MrScautHDOP•10mo ago

Euler angles could be everything It could -390 but it could 30

    public unsafe bool AreQuaternionsLookingSameDirection(Quaternion q1, Quaternion q2) {
        Vector3 axis1;
        float angle1;
        
        Raymath.QuaternionToAxisAngle(q1, &axis1, &angle1);
        
        Vector3 axis2;
        float angle2;
        
        Raymath.QuaternionToAxisAngle(q2, &axis2, &angle2);
        
        
        Quaternion quaternion1 = Quaternion.CreateFromAxisAngle(Vector3.UnitY, 30 * Raylib.DEG2RAD);
        Quaternion quaternion2 = Quaternion.CreateFromAxisAngle(Vector3.UnitY, 391 * Raylib.DEG2RAD);
        
        //Quaternion quaternion1 = Quaternion.CreateFromAxisAngle(axis1, angle1);
        //Quaternion quaternion2 = Quaternion.CreateFromAxisAngle(axis2, angle2);
        
        // Define a common point (e.g., the origin)
        Vector3 point = Vector3.UnitZ;

        // Rotate the point using both quaternions
        Vector3 rotatedPoint1 = Vector3.Transform(point, quaternion1);
        Vector3 rotatedPoint2 = Vector3.Transform(point, quaternion2);

        // Calculate the distance between the two rotated points
        float distance = Vector3.Distance(rotatedPoint1, rotatedPoint2);

        // Define a tolerance for distance comparison
        float tolerance = 0.001f; // Adjust as needed

        // Check if the distance is within the tolerance
        return distance < tolerance;
    }

    public unsafe bool AreQuaternionsLookingSameDirection(Quaternion q1, Quaternion q2) {
        Vector3 axis1;
        float angle1;
        
        Raymath.QuaternionToAxisAngle(q1, &axis1, &angle1);
        
        Vector3 axis2;
        float angle2;
        
        Raymath.QuaternionToAxisAngle(q2, &axis2, &angle2);
        
        
        Quaternion quaternion1 = Quaternion.CreateFromAxisAngle(Vector3.UnitY, 30 * Raylib.DEG2RAD);
        Quaternion quaternion2 = Quaternion.CreateFromAxisAngle(Vector3.UnitY, 391 * Raylib.DEG2RAD);
        
        //Quaternion quaternion1 = Quaternion.CreateFromAxisAngle(axis1, angle1);
        //Quaternion quaternion2 = Quaternion.CreateFromAxisAngle(axis2, angle2);
        
        // Define a common point (e.g., the origin)
        Vector3 point = Vector3.UnitZ;

        // Rotate the point using both quaternions
        Vector3 rotatedPoint1 = Vector3.Transform(point, quaternion1);
        Vector3 rotatedPoint2 = Vector3.Transform(point, quaternion2);

        // Calculate the distance between the two rotated points
        float distance = Vector3.Distance(rotatedPoint1, rotatedPoint2);

        // Define a tolerance for distance comparison
        float tolerance = 0.001f; // Adjust as needed

        // Check if the distance is within the tolerance
        return distance < tolerance;
    }

i made it work bit messy right now but this works! thx guys!

bighugemassive3•10mo ago

I think you can mod the components with 360 though? double x = vec1.X % 360 Not too sure though, haven't done 3d stuff in a while

MrScautHDOP•10mo ago

fixed it already, but anyways thx

Gaming

Programming

Hey guys, how can i check if my 2 Quaternions looking in the same direction?