ScriptableRenderPipeline/com.unity.render-pipelines.high-definition/HDRP/Sky/AtmosphericScattering/ExponentialFog.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering;

namespace UnityEngine.Experimental.Rendering.HDPipeline
{
    public class ExponentialFog : AtmosphericScattering
    {
        private readonly static int m_ExpFogParam = Shader.PropertyToID("_ExpFogParameters");

        public MinFloatParameter        fogDistance = new MinFloatParameter(200.0f, 0.0f);
        public FloatParameter           fogBaseHeight = new FloatParameter(0.0f);
        public ClampedFloatParameter    fogHeightAttenuation = new ClampedFloatParameter(0.2f, 0.0f, 1.0f);

        public override void PushShaderParameters(HDCamera hdCamera, CommandBuffer cmd)
        {
            PushShaderParametersCommon(hdCamera, cmd, FogType.Exponential);
            cmd.SetGlobalVector(m_ExpFogParam, new Vector4(Mathf.Max(1e-6f, fogDistance), fogBaseHeight, fogHeightAttenuation, 0.0f));
        }
    }
}