using System;
using UnityEngine.Rendering;

namespace UnityEngine.Experimental.Rendering.HDPipeline
{
    [Serializable]
    public sealed class LitProjectionModelParameter : VolumeParameter<ScreenSpaceReflection.AvailableProjectionModel>
    {
        public LitProjectionModelParameter() : base(ScreenSpaceReflection.AvailableProjectionModel.Proxy, false) {}
    }

    [Serializable]
    public class ScreenSpaceReflection : ScreenSpaceLighting
    {
        // Values must be in sync with ScreenSpaceLighting.ProjectionModel
        public enum AvailableProjectionModel
        {
            None = 0,
            Proxy = 1,
            HiZ = 2
        }

        static ScreenSpaceReflection s_Default = null;
        public static ScreenSpaceReflection @default
        {
            get
            {
                if (s_Default == null)
                {
                    s_Default = ScriptableObject.CreateInstance<ScreenSpaceReflection>();
                    s_Default.hideFlags = HideFlags.HideAndDontSave;
                }
                return s_Default;
            }
        }

        int m_DeferredProjectionModel;

        public LitProjectionModelParameter                 deferredProjectionModel = new LitProjectionModelParameter();

        protected override void FetchIDs(
            out int rayLevelID,
            out int rayMinLevelID,
            out int rayMaxLevelID,
            out int rayMaxIterationsID,
            out int depthBufferThicknessID,
            out int screenWeightDistanceID,
            out int rayMaxScreenDistanceID,
            out int rayBlendScreenDistanceID,
            out int rayMarchBehindObjectsID
            )
        {
            rayLevelID = HDShaderIDs._SSReflectionRayLevel;
            rayMinLevelID = HDShaderIDs._SSReflectionRayMinLevel;
            rayMaxLevelID = HDShaderIDs._SSReflectionRayMaxLevel;
            rayMaxIterationsID = HDShaderIDs._SSReflectionRayMaxIterations;
            depthBufferThicknessID = HDShaderIDs._SSReflectionDepthBufferThickness;
            screenWeightDistanceID = HDShaderIDs._SSReflectionInvScreenWeightDistance;
            rayMaxScreenDistanceID = HDShaderIDs._SSReflectionRayMaxScreenDistance;
            rayBlendScreenDistanceID = HDShaderIDs._SSReflectionRayBlendScreenDistance;
            rayMarchBehindObjectsID = HDShaderIDs._SSReflectionRayMarchBehindObjects;
        }

        public override void PushShaderParameters(CommandBuffer cmd)
        {
            base.PushShaderParameters(cmd);
            cmd.SetGlobalInt(HDShaderIDs._SSReflectionProjectionModel, (int)deferredProjectionModel.value);
        }
    }
}