Perekyp/Assets/Scripts/Car/Visuals/CarPartVisuals.cs

using UnityEngine;

[RequireComponent(typeof(Renderer))]
public class CarPartVisuals : MonoBehaviour
{
    private Renderer partRenderer;
    private MaterialPropertyBlock propertyBlock;

    private static readonly int RustAmountProp = Shader.PropertyToID("_RustAmount");
    private static readonly int BaseColorProp = Shader.PropertyToID("_BaseColor");

    [Range(0f, 1f)] [SerializeField] private float currentRust = 0f;
    [SerializeField] private Color currentColor = Color.white;

    public float CurrentRust => currentRust;
    public Color CurrentColor => currentColor;

    private void Awake()
    {
        partRenderer = GetComponent<Renderer>();
        propertyBlock = new MaterialPropertyBlock();
    }

    public void SetRust(float amount)
    {
        currentRust = Mathf.Clamp01(amount);
        ApplyProperties();
    }

    public void SetPaintColor(Color newColor)
    {
        currentColor = newColor;
        ApplyProperties();
    }

    private void ApplyProperties()
    {
        if (partRenderer == null) return;

        partRenderer.GetPropertyBlock(propertyBlock);
        propertyBlock.SetFloat(RustAmountProp, currentRust);
        propertyBlock.SetColor(BaseColorProp, currentColor);
        partRenderer.SetPropertyBlock(propertyBlock);
    }
}