unity hdrp.

// VolumeOverrides.cs — a HDRP volume profile authored in C#.
// Drop this on a GameObject with a Volume component; HDRP picks
// up the overrides automatically and blends them per camera.
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.HighDefinition;

[RequireComponent(typeof(Volume))]
public class VolumeOverrides : MonoBehaviour
{
    [SerializeField] private float fogDensity = 0.04f;
    [SerializeField] private Color fogColor   = new Color(0.54f, 0.62f, 0.75f);
    [SerializeField] private float exposure   = 1.4f;

    private VolumeProfile profile;

    void Awake()
    {
        profile = GetComponent<Volume>().sharedProfile;

        // Fog override — exponential, with custom color tint.
        if (profile.TryGet<Fog>(out var fog))
        {
            fog.enabled.value      = true;
            fog.meanFreePath.value = 1f / fogDensity;
            fog.albedo.value       = fogColor;
        }

        // Exposure override — fixed mode, EV value derived from input.
        if (profile.TryGet<Exposure>(out var ex))
        {
            ex.mode.value     = ExposureMode.Fixed;
            ex.fixedExposure.value = Mathf.Log(exposure, 2f);
        }

        // Color adjustments — saturation pull and a subtle hue shift.
        if (profile.TryGet<ColorAdjustments>(out var color))
        {
            color.saturation.value = -12f;
            color.hueShift.value   = 8f;
        }

        // Bloom — subtle, not the wedding-cake kind.
        if (profile.TryGet<Bloom>(out var bloom))
        {
            bloom.intensity.value = 0.35f;
            bloom.scatter.value   = 0.7f;
        }
    }

    // HDRP's VolumeManager handles the blend. You don't.
    // Camera position + volume priority + falloff radius do the
    // arithmetic every frame.
}