A method to slide camera along an obstacle in a 3D world.

SlideCameraOnCollision.cs

//Copyright © 2017 Manoj M J
//All Rights Reserved

/*
A method to slide camera along an obstacle.
Note: This script uses Unity3D game engine api and libraries.
*/
void SlideCameraOnCollision(
        Vector3 obstacleNormal, 
        Vector3 cameraForward, 
        float   forwardInputMagnitude,
        Transform cameraTransform,
        float slidingSpeed,
        float movementSmoothening
        )
{
    Vector3 side = 
		Vector3.Cross(cameraForward, obstacleNormal);
    Vector3 tangent = 
		(Vector3.Cross(side, obstacleNormal)).normalized;
    cameraTransform.position = 
		Vector3.Lerp(cameraTransform.position,
            cameraTransform.position - 
            tangent * (forwardInputMagnitude * slidingSpeed),
            movementSmoothening * Time.deltaTime);
}

//Driver code
void Update()
{
	//...
	SlideCameraOnCollision(raycasthitInfo.normal, 
						fwd, 
						Input.GetAxis("Vertical"), 
						CameraTransform, 
						SlidingSpeed,
						MovementSmoothening);
	//...
}