FPS RigidBody Walker Jump

Unity Engine
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1

I’m using logic based off the FPS RigidBody walker in the wiki so I have a snappy, clamped, rigidbody controller.
The input to movement goes like this:

// Get Input()
inputVector = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
inputVector.Normalize();
targetDirection = transform.TransformDirection(inputVector);
targetVelocity = targetDirection;

targetVelocity *= airControl;

// Apply a force that attempts to reach our target velocity
Vector3 velocity = rigidbody.velocity;
Vector3 velocityChange = (targetVelocity - velocity);
velocityChange.x = Mathf.Clamp(velocityChange.x, -maxVelocityChange, maxVelocityChange);
velocityChange.z = Mathf.Clamp(velocityChange.z, -maxVelocityChange, maxVelocityChange);
velocityChange.y = 0;
rigidbody.AddForce(velocityChange, ForceMode.VelocityChange);

The problem is when I want to jump the same logic makes the character slow down to a stop in the air instead of preserving the momentum. Since I have a slower speed for in-air movement, even if I press in the direction of the jump it slows down from the intial speed I had when I pressed jump.

I want to preserve the original speed vector at the moment of jumping while also applying the above logic for any additional and precise air movement.

I understand I need to save the original speed, find the component of my input vector that is parallel to the original speed and take it into account somehow. In words:

  1. Take my input vector’s component that is parallel to the original speed (project the input on the speed)
  2. If the projected component is in the same direction of the speed, ignore it when calculating velocityChange ( I still want to be able to slow down if my input is in the opposite direction )

What I can’t figure out is how to take the projected component into account so it will be ignored when calculating the velocityChange:

// Start Jump
originalSpeed =  new Vector3(rigidbody.velocity.x, 0, rigidbody.velocity.z);       
rigidbody.velocity = new Vector3(rigidbody.velocity.x, CalculateJumpVerticalSpeed(), rigidbody.velocity.z);

// Project input on original speed vector
Vector3 projectedInput = Vector3.Project(targetVelocity, originalSpeed.normalized);
float dotProduct = Vector3.Dot(projectedInput, originalSpeed);

// Take into consideration the projectedInput in case it is parallel to originalSpeed
if(dotProduct == 1)
    // ????????????
2

After spending a day away from the code I found a much simple approach to it.
When comparing with current rigidbody.veloicty when calculating the velocityChange I substract the original velocty

Hope this will help someone in the future:

Use this

Vector3 velocity = rigidbody.velocity - originalSpeed;

Instead of this

Vector3 velocity = rigidbody.velocity;