Stop building momentum when running into a wall. (2D Top-Down) - unity3d

Question

So my movement isn't instant. You accelerate and decelerate. I use two floats starting at 0, going to 1, to calculate my movement speed. Here it is:
private void Update()
{
float moveTowardsX = 0;
float moveTowardsY = 0;
// Adjust thrust to be below max Thrust
if(thrust >= maxThrust)
{
thrust = maxThrust;
}
// Calculates movement speed based on all variables
float changeRatePerSecond = 1 / timeFromZeroToMax * thrust * Time.deltaTime;
changeRatePerSecond /= weight / 1.5f;
if(onMobile == true)
{
// Checks for Input. If Input is detected, values get changed [MOBILE]
if(isMovingLeft == true && isMovingRight == false)
{
moveTowardsX = -1.0f;
}
else if(isMovingRight == true && isMovingLeft == false)
{
moveTowardsX = 1.0f;
}
if(isMovingUp == true && isMovingDown == false)
{
moveTowardsY = 1.0f;
}
else if(isMovingDown == true && isMovingUp == false)
{
moveTowardsY = -1.0f;
}
if(isRotatingLeft == true && isRotatingRight == false)
{
rotationsPerSecond++;
}
else if(isRotatingRight == true && isRotatingLeft == false)
{
rotationsPerSecond--;
}
}
Then I parse these values into my movement code and smooth them out:
void FixedUpdate()
{
// Makes values change smoothly
valueX = Mathf.MoveTowards(valueX, moveTowardsX, changeRatePerSecond);
valueY = Mathf.MoveTowards(valueY, moveTowardsY, changeRatePerSecond);
// Turn numbers into movement
rb.velocity = new Vector2(valueX * runSpeed, valueY * runSpeed);
}
The Problem is that when I run into a wall, the numbers don't decrease. And if I run into a wall standing still, the numbers increase. Here is a video linking to my problem too (Look at the top right): https://youtu.be/XRE9p0yo4GA
What could I implement to fix this?

Answer 1

I have 2 suggestions, either one should work:
Do a ground check. Platformers often perform ground checks to check that the player is on the ground. By doing a box cast, you can check if your character is adjacent to a wall in the direction of their movement, and if they are, do not let them move (or gain speed) in that direction.
Here is a video for how to do a ground check. I would recommend the box cast method here, since it would give you the most accurate results:
https://www.youtube.com/watch?v=c3iEl5AwUF8
Use the rb.velocity of the object in a direction divided by your character's maximum speed in place of your valueX and valueY. So, use:
rb.velocity.x / runSpeed
instead of
valueX
and the same for y. This would take into account anything that changes the velocity of the object outside this script, such as crashing into a wall, but also if your character is thrown by some effect you create later on.