//-----------------------------------------------------------------------------
// structure definition
//-----------------------------------------------------------------------------
using UnityEngine.Rendering.HighDefinition.Attributes;
using UnityEngine.Experimental.Rendering;

namespace UnityEngine.Rendering.HighDefinition
{
    class Builtin // Note: This particular class doesn't derive from RenderPipelineMaterial
    {
        //-----------------------------------------------------------------------------
        // BuiltinData
        // This structure include common data that should be present in all material
        // and are independent from the BSDF parametrization.
        // Note: These parameters can be store in GBuffer or not depends on storage available
        //-----------------------------------------------------------------------------
        [GenerateHLSL(PackingRules.Exact, false, false, true, 100)]
        public struct BuiltinData
        {
            [MaterialSharedPropertyMapping(MaterialSharedProperty.Alpha)]
            [SurfaceDataAttributes("Opacity", precision = FieldPrecision.Real)]
            public float opacity;

            [SurfaceDataAttributes("AlphaClipTreshold", precision = FieldPrecision.Real)]
            public float alphaClipTreshold;

            // These are lighting data.
            // We would prefer to split lighting and material information but for performance reasons,
            // those lighting information are fill
            // at the same time than material information.
            [SurfaceDataAttributes("Baked Diffuse Lighting", false, true, FieldPrecision.Real)]
            public Vector3 bakeDiffuseLighting; // This is the result of sampling lightmap/lightprobe/proxyvolume
            [SurfaceDataAttributes("Back Baked Diffuse Lighting", false, true, FieldPrecision.Real)]
            public Vector3 backBakeDiffuseLighting; // This is the result of sampling lightmap/lightprobe/proxyvolume from the back for transmission

            // Use for float instead of vector4 to ease the debug (no performance impact)
            // Note: We have no way to remove these value automatically based on either SHADEROPTIONS_BAKED_SHADOW_MASK_ENABLE or s_BakedShadowMaskEnable here. Unless we make two structure... For now always keep this value
            [SurfaceDataAttributes("Shadowmask 0", precision = FieldPrecision.Real)]
            public float shadowMask0;
            [SurfaceDataAttributes("Shadowmask 1", precision = FieldPrecision.Real)]
            public float shadowMask1;
            [SurfaceDataAttributes("Shadowmask 2", precision = FieldPrecision.Real)]
            public float shadowMask2;
            [SurfaceDataAttributes("Shadowmask 3", precision = FieldPrecision.Real)]
            public float shadowMask3;

            [SurfaceDataAttributes("Emissive Color", false, false, FieldPrecision.Real)]
            public Vector3 emissiveColor;

            // These is required for motion blur and temporalAA
            [SurfaceDataAttributes("Motion Vector", precision = FieldPrecision.Real)]
            public Vector2 motionVector;

            // Distortion
            [SurfaceDataAttributes("Distortion", precision = FieldPrecision.Real)]
            public Vector2 distortion;
            [SurfaceDataAttributes("Distortion Blur", precision = FieldPrecision.Real)]
            public float distortionBlur;           // Define the color buffer mipmap level to use

            // Misc
            [SurfaceDataAttributes("Rendering Layers")]
            public uint renderingLayers;

            [SurfaceDataAttributes("Depth Offset")]
            public float depthOffset; // define the depth in unity unit to add in Z forward direction

            [SurfaceDataAttributes("VT Packed Feedback", precision = FieldPrecision.Real)]
            public Vector4 vtPackedFeedback;
        };

        //-----------------------------------------------------------------------------
        // LightTransportData
        // This struct is use to store information for Enlighten/Progressive light mapper. both at runtime or off line.
        //-----------------------------------------------------------------------------
        [GenerateHLSL(PackingRules.Exact, false)]
        public struct LightTransportData
        {
            [SurfaceDataAttributes("", false, true, FieldPrecision.Real)]
            public Vector3 diffuseColor;
            [SurfaceDataAttributes(precision = FieldPrecision.Real)]
            public Vector3 emissiveColor; // HDR value
        };

        public static GraphicsFormat GetLightingBufferFormat()
        {
            return GraphicsFormat.B10G11R11_UFloatPack32;
        }

        public static GraphicsFormat GetShadowMaskBufferFormat()
        {
            return GraphicsFormat.R8G8B8A8_UNorm;
        }

        public static GraphicsFormat GetMotionVectorFormat()
        {
            return GraphicsFormat.R16G16_SFloat; // TODO: We should use 16bit normalized instead, better precision // RGInt
        }

        public static GraphicsFormat GetDistortionBufferFormat()
        {
            // TODO: // This format need to be additive blendable and include distortionBlur, blend mode different for alpha value
            return GraphicsFormat.R16G16B16A16_SFloat;
        }
    }
}