// Shader targeted for low end devices. Single Pass Forward Rendering. Shader Model 2
Shader "LightweightPipeline/Standard (Simple Lighting)"
{
    // Keep properties of StandardSpecular shader for upgrade reasons.
    Properties
    {
        _Color("Color", Color) = (1,1,1,1)
        _MainTex("Base (RGB) Glossiness / Alpha (A)", 2D) = "white" {}

        _Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5

        _Shininess("Shininess", Range(0.01, 1.0)) = 1.0
        _GlossMapScale("Smoothness Factor", Range(0.0, 1.0)) = 1.0

        _Glossiness("Glossiness", Range(0.0, 1.0)) = 0.5
        [Enum(Specular Alpha,0,Albedo Alpha,1)] _SmoothnessTextureChannel("Smoothness texture channel", Float) = 0

        [HideInInspector] _SpecSource("Specular Color Source", Float) = 0.0
        _SpecColor("Specular", Color) = (1.0, 1.0, 1.0)
        _SpecGlossMap("Specular", 2D) = "white" {}
        [HideInInspector] _GlossinessSource("Glossiness Source", Float) = 0.0
        [ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
        [ToggleOff] _GlossyReflections("Glossy Reflections", Float) = 1.0

        [HideInInspector] _BumpScale("Scale", Float) = 1.0
        [NoScaleOffset] _BumpMap("Normal Map", 2D) = "bump" {}

        _Parallax("Height Scale", Range(0.005, 0.08)) = 0.02
        _ParallaxMap("Height Map", 2D) = "black" {}

        _EmissionColor("Emission Color", Color) = (0,0,0)
        _EmissionMap("Emission", 2D) = "white" {}

        _DetailMask("Detail Mask", 2D) = "white" {}

        _DetailAlbedoMap("Detail Albedo x2", 2D) = "grey" {}
        _DetailNormalMapScale("Scale", Float) = 1.0
        _DetailNormalMap("Normal Map", 2D) = "bump" {}

        [Enum(UV0,0,UV1,1)] _UVSec("UV Set for secondary textures", Float) = 0

        // Blending state
        [HideInInspector] _Mode("__mode", Float) = 0.0
        [HideInInspector] _SrcBlend("__src", Float) = 1.0
        [HideInInspector] _DstBlend("__dst", Float) = 0.0
        [HideInInspector] _ZWrite("__zw", Float) = 1.0
    }

    SubShader
    {
        Tags { "RenderType" = "Opaque" "RenderPipeline" = "LightweightPipeline" }
        LOD 300

        Pass
        {
            Tags { "LightMode" = "LightweightForward" }

            // Use same blending / depth states as Standard shader
            Blend[_SrcBlend][_DstBlend]
            ZWrite[_ZWrite]

            CGPROGRAM
            #pragma target 3.0
            #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON
            #pragma shader_feature _ _SPECGLOSSMAP _SPECULAR_COLOR
            #pragma shader_feature _ _GLOSSINESS_FROM_BASE_ALPHA
            #pragma shader_feature _NORMALMAP
            #pragma shader_feature _EMISSION

            #pragma multi_compile _ _MAIN_LIGHT_COOKIE
            #pragma multi_compile _MAIN_DIRECTIONAL_LIGHT _MAIN_SPOT_LIGHT _MAIN_POINT_LIGHT
            #pragma multi_compile _ _ADDITIONAL_LIGHTS
            #pragma multi_compile _ UNITY_SINGLE_PASS_STEREO STEREO_INSTANCING_ON STEREO_MULTIVIEW_ON
            #pragma multi_compile _ LIGHTMAP_ON
            #pragma multi_compile _ DIRLIGHTMAP_COMBINED
            #pragma multi_compile _ _HARD_SHADOWS _SOFT_SHADOWS _HARD_SHADOWS_CASCADES _SOFT_SHADOWS_CASCADES
            #pragma multi_compile _ _VERTEX_LIGHTS
            #pragma multi_compile_fog
            #pragma multi_compile_instancing

            #pragma vertex LitPassVertex
            #pragma fragment LitPassFragmentSimple
            #include "LightweightPassLit.cginc"
            ENDCG
        }

        Pass
        {
            Tags{"Lightmode" = "ShadowCaster"}

            ZWrite On ZTest LEqual

            CGPROGRAM
            #pragma target 2.0
            #pragma vertex ShadowPassVertex
            #pragma fragment ShadowPassFragment

            #include "UnityCG.cginc"
            #include "LightweightPassShadow.cginc"
            ENDCG
        }

        Pass
        {
            Tags{"Lightmode" = "DepthOnly"}

            ZWrite On
            ColorMask 0

            CGPROGRAM
            #pragma target 2.0
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            float4 vert(float4 pos : POSITION) : SV_POSITION
            {
                return UnityObjectToClipPos(pos);
            }

            half4 frag() : SV_TARGET
            {
                return 0;
            }
            ENDCG
        }

        // This pass it not used during regular rendering, only for lightmap baking.
        Pass
        {
            Tags{ "LightMode" = "Meta" }

            Cull Off

            CGPROGRAM
            #define UNITY_SETUP_BRDF_INPUT SpecularSetup
            #pragma vertex LightweightVertexMeta
            #pragma fragment LightweightFragmentMeta

            #pragma shader_feature _EMISSION
            #pragma shader_feature _SPECGLOSSMAP
            #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
            #pragma shader_feature ___ _DETAIL_MULX2
            #pragma shader_feature EDITOR_VISUALIZATION

            #include "LightweightPassLit.cginc"
            #include "UnityMetaPass.cginc"

            struct MetaVertexInput
            {
                float4 vertex   : POSITION;
                half3 normal    : NORMAL;
                float2 uv0      : TEXCOORD0;
                float2 uv1      : TEXCOORD1;
                float2 uv2      : TEXCOORD2;
#ifdef _TANGENT_TO_WORLD
                half4 tangent   : TANGENT;
#endif
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct MetaVertexOuput
            {
                float4 pos      : SV_POSITION;
                float2 uv       : TEXCOORD0;
            };

            MetaVertexOuput LightweightVertexMeta(MetaVertexInput v)
            {
                MetaVertexOuput o;
                o.pos = UnityMetaVertexPosition(v.vertex, v.uv1.xy, v.uv2.xy, unity_LightmapST, unity_DynamicLightmapST);
                o.uv = TRANSFORM_TEX(v.uv0, _MainTex);
                return o;
            }

            fixed4 LightweightFragmentMeta(MetaVertexOuput i) : SV_Target
            {
                UnityMetaInput o;
                UNITY_INITIALIZE_OUTPUT(UnityMetaInput, o);

                o.Albedo = _Color.rgb * tex2D(_MainTex, i.uv).rgb;
                o.SpecularColor = SpecularGloss(i.uv.xy, 1.0);

#ifdef _EMISSION
                o.Emission += LIGHTWEIGHT_GAMMA_TO_LINEAR(tex2D(_EmissionMap, i.uv).rgb) * _EmissionColor;
#else
                o.Emission += _EmissionColor;
#endif

                return UnityMetaFragment(o);
            }
            ENDCG
        }
    }
    Fallback "Standard (Specular setup)"
    CustomEditor "LightweightStandardSimpleLightingGUI"
}