This character controller is my attempt at a "one size fits all" solution for a 3D character controller. It's implemented using the "collide and slide" algorithm, outlined by Kasper Fauerby in his paper, "Improved Collision detection and Response", and iterated on by Jeff Linahan in "Improving the Numerical Robustness of Sphere Swept Collision Detection."

I made a video showcasing and explaining the original algorithm and my implementation here:
https://youtu.be/YR6Q7dUz2uk

and a follow-up video covering Linahan's improved algorithm, as well as stair detection, here:
TBA

This controller can be used in both first and third-person games. All you need to do is provide a normalized moveDir.

public Vector3 Move(Vector2 moveDir, bool shouldJump);

Moves the attached rigidbody in the desired direction, taking into account gravity, collisions, and slopes, using the "collide and slide" algorithm. Returns the current velocity.

Parameters
moveAmount: Vector2
A normalized 2D vector representing the current direction the player wants to move (NOT scaled by deltaTime).
shouldJump: bool
Whether or not the controller should try to jump this frame.

Returns
Vector3
A 3D vector representing the controller's new (unscaled) velocity after gravity and collisions.

My character controller currently supports

• Custom collision detection
• Ground/ceiling detection
• Smooth movement on slopes, plus sliding down steep slopes\
• Climbing/descending stairs
• Parameterized jump height and distance
  • Gravity is set based on these two values
• Coyote Time
• Crouching
• Extensible movement behavior using Character Motor components (see below)

My character controller currently does not support

• Colliding with other characters
• Moving platforms
• Flying, swimming, noclipping, or any other niche form of movement
• Networking/multiplayer

The Kinematic Character Controller accelerates based on the methods provided by a Character Motor component, which implements the ICharacterMotor interface.

public interface ICharacterMotor {
    Vector3 Accelerate(Vector3 wishDir, Vector3 currentVel);
}

Sample character motor implementations can be found in /Assets/CharacterController/Motors/.