Quaternion from Direction Vector

Help & Support
1

Is there a simple way to set an object’s quaternion rotation from a 3d unit vector pointing at any direction?

2

How about:

// Create random vector in any direction
var dirVec = new pc.Vec3(Math.random() * 2 - 1, Math.random() * 2 - 1, Math.random() * 2 - 1);
dirVec.normalize();

var quat = new pc.Quat();
quat.setFromAxisAngle(dirVec, 0);

entity.setRotation(quat);
3

Just needed this aswell, so I fit the Unity function to PlayCanvas:

    LookRotation = function(forward, up)
    {
        forward = forward.normalize();
 
        //var vector = forward.normalize();
        //var vector2 = up.CrossProduct(vector).Normalize();
        //var vector3 = vector.CrossProduct(vector2);
        var vector = forward.normalize();
        var vector2 = (new pc.Vec3()).cross(up, vector).normalize();
        var vector3 = (new pc.Vec3()).cross(vector, vector2);
        var m00 = vector2.x;
        var m01 = vector2.y;
        var m02 = vector2.z;
        var m10 = vector3.x;
        var m11 = vector3.y;
        var m12 = vector3.z;
        var m20 = vector.x;
        var m21 = vector.y;
        var m22 = vector.z;
 
        var num8 = (m00 + m11) + m22;
        var quaternion = new pc.Quat;
        if (num8 > 0.0)
        {
            var num = Math.sqrt(num8 + 1.0);
            quaternion.w = num * 0.5;
            num = 0.5 / num;
            quaternion.x = (m12 - m21) * num;
            quaternion.y = (m20 - m02) * num;
            quaternion.z = (m01 - m10) * num;
            return quaternion;
        }
        if ((m00 >= m11) && (m00 >= m22))
        {
            var num7 = Math.sqrt(((1.0 + m00) - m11) - m22);
            var num4 = 0.5 / num7;
            quaternion.x = 0.5 * num7;
            quaternion.y = (m01 + m10) * num4;
            quaternion.z = (m02 + m20) * num4;
            quaternion.w = (m12 - m21) * num4;
            return quaternion;
        }
        if (m11 > m22)
        {
            var num6 = Math.sqrt(((1.0 + m11) - m00) - m22);
            var num3 = 0.5 / num6;
            quaternion.x = (m10 + m01) * num3;
            quaternion.y = 0.5 * num6;
            quaternion.z = (m21 + m12) * num3;
            quaternion.w = (m20 - m02) * num3;
            return quaternion;
        }
        var num5 = Math.sqrt(((1.0 + m22) - m00) - m11);
        var num2 = 0.5 / num5;
        quaternion.x = (m20 + m02) * num2;
        quaternion.y = (m21 + m12) * num2;
        quaternion.z = 0.5 * num5;
        quaternion.w = (m01 - m10) * num2;
        return quaternion;
    }

Original: https://answers.unity.com/questions/467614/what-is-the-source-code-of-quaternionlookrotation.html
Unity Documentation: https://docs.unity3d.com/ScriptReference/Quaternion.LookRotation.html

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