The Player class includes code to update the health bar UI based on the player's current health. This is managed through three variables: UIHealthTransform, HealthUIScale, and startingHealthUIWidth. Below is an explanation of how these variables are used to manage the health bar.

Script for Health Bar

// Initialization in Start method
private void Start()
{
    HealthUIScale = UIHealthTransform.sizeDelta;
    startingHealthUIWidth = HealthUIScale.x;
}

// Updating health in GetAttacked method
public void GetAttacked(int damage)
{
    if (isDead) return;
    health -= damage;
    HealthUIScale.x = health * startingHealthUIWidth / 100f;
    UIHealthTransform.sizeDelta = HealthUIScale;
    if (health <= 0)
    {
        isDead = true;
        animator.SetBool("death", true);
        var deathParticle = Instantiate(deathParticles, transform.position, Quaternion.identity);
        deathParticle.Play();
        Destroy(deathParticle.gameObject, 5);
        GameManager.instance.FinishGame();
    }
}

Initialization in Start Method

In the Start method, the initial size of the health bar is captured and stored.

private void Start()
{
    // ... other initializations ...
    HealthUIScale = UIHealthTransform.sizeDelta;
    startingHealthUIWidth = HealthUIScale.x;
}

Health Update in GetAttacked Method

The GetAttacked method updates the health bar UI whenever the player takes damage.

Health Reduction:

health -= damage;

The player's health is reduced by the amount of damage taken.

Health Bar Scale Calculation:

HealthUIScale.x = health * startingHealthUIWidth / 100f;

Explanation

This line of code updates the width of the health bar based on the player's current health. Here’s how it works:

Health: health is a float representing the player's current health. Let's assume it ranges from 0 to 100.

Starting Health Bar Width: startingHealthUIWidth is a float representing the initial width of the health bar when the player has full health.

Scaling the Health Bar Width: The goal is to proportionally reduce the width of the health bar as the player's health decreases; To achieve this, you need to calculate what percentage of the player's health remains and then apply that percentage to the initial width of the health bar.

Step-by-Step Calculation

Percentage of Health Remaining: Divide the current health by 100 to obtain a value between 0 and 1 representing the percentage of the player's health remaining. For instance, if the player's health is 75, health / 100f would yield 0.75. This calculation translates the health value into a percentage format suitable for UI representation.

Apply Percentage to Initial Width:

Multiply the percentage of health remaining by the initial width of the health bar. For example, if the startingHealthUIWidth is 200 (the full width), and the player's health is 75%, the new width of the health bar would be 150 units (0.75 * 200 = 150).

By using this calculation, the health bar's width dynamically and accurately represents the player's current health, providing clear visual feedback to the player.

Update Health Bar UI:

UIHealthTransform.sizeDelta = HealthUIScale;

The size of the RectTransform representing the health bar is updated.

Check for Player Death:

if (health <= 0)
{
    isDead = true;
    animator.SetBool("death", true);
    var deathParticle = Instantiate(deathParticles, transform.position, Quaternion.identity);
    deathParticle.Play();
    Destroy(deathParticle.gameObject, 5);
    GameManager.instance.FinishGame();
}

If the health drops to 0 or below, the player is marked as dead, and the death animation and particles are triggered.

Summary of Health Bar UI Functionality

Initialization: The initial size of the health bar is captured at the start.

Updating Health Bar: When the player takes damage, the health value is decreased, and the width of the health bar is recalculated and updated accordingly.

Player Death: If health reaches zero, the player is marked as dead, triggering the death animation and particles, and finishing the game.