Shader "NLD_URP/NLD_Scene_Lambert"
{
    Properties
    {
        // [MainColor] _BaseColor ("Main Color", color) = (1,1,1,1)
        [MainTexture] _MainTex ("Texture", 2D) = "white" {}
        _MaskTex ("Mask", 2D) = "white" {}
        _OutlineColor("Outline Color",color)=(0.1,0.1,0.2,1)
        _Outline("Thick of Outline",range(0,0.1))=0.02
        _Factor("Factor",range(0,1)) = 0.5
        _Smoothness("Smoothness", range(0,1.0)) = 0.5
        _shadowScale("ShadowScale", range(0, 1.0)) = 0.5
        _specularScaleB("SpecularScaleB", range(0, 10.0)) = 2.0
        
        _Gloss("Gloss", range(0, 10.0)) = 2.0
        _SpecialColor("SpecialColor", color) = (1,1,1,1)
        _SpecialStrengh("_SpecialStrengh", range(0, 10.0)) = 1
        _DiffuseStrengh("DiffuseStrengh", range(0, 10)) = 1
        _MinDiffuse("MinDiffuse", range(0, 1)) = 0.1

    }
    SubShader
    {
        Tags { 
            "RenderType"="Opaque"
            "RenderPipeline" = "UniversalPipeline"
        }
        LOD 100
        
        HLSLINCLUDE

        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

        struct appdata
        {
            float4 positionOS : POSITION;
            float3 normal : NORMAL;
            float4 tangent : TANGENT;
            float2 uv : TEXCOORD0;
        };

        struct v2f
        {
            float2 uv : TEXCOORD0;
            float4 positionHCS : SV_POSITION;
            float3 normalWS : TEXCOORD1;
            float3 positionWS : TEXCOORD02;
        };

        TEXTURE2D(_MainTex);
        SAMPLER(sampler_MainTex);

        TEXTURE2D(_MaskTex);
        SAMPLER(sampler_MaskTex);

        CBUFFER_START(UnityPerMaterial)
            float4 _MainTex_ST;
            float4 _MaskTex_ST;
                
            float _Smoothness;
            float _specularScaleB;
            float _specularScaleG;
            float _shadowScale;

            float _Gloss;
            float4 _SpecialColor;
            float _SpecialStrengh;
            float _DiffuseStrengh;
            float _MinDiffuse;

            float _Outline;
            float4 _OutlineColor;
            float _Factor;
        CBUFFER_END
        
        ENDHLSL

        Pass
        {
            Cull Back
            Name "ForwardLit"
            Tags {
                "LightMode" = "UniversalForward"
            }
            Blend Off
            
            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            // 开启接收阴影
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS //主光源阴影
            #pragma multi_compile _ _SHADOWS_SOFT //软阴影

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
            

            v2f vert (appdata v)
            {
                v2f o;
                
                o.positionHCS = TransformObjectToHClip(v.positionOS.xyz);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                o.normalWS = TransformObjectToWorldNormal(v.normal);
                o.positionWS = TransformObjectToWorld(v.positionOS);
                return o;
            }

            half4 frag (const v2f i) : SV_Target
            {
                // sample the texture
                half4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv);
                if (color.a < 0.5) discard;
                // AlphaDiscard(color.a, 0.5);
                color.a = 1;

                half4 colorMask = SAMPLE_TEXTURE2D(_MaskTex, sampler_MaskTex, i.uv);

                //当前模型接收阴影
                float4 SHADOW_COORDS = TransformWorldToShadowCoord(i.positionWS);
                //放入光照数据
                Light  lightData = GetMainLight(SHADOW_COORDS, i.positionWS, 1);
                //多光照阴影数据
                half shadow = lightData.shadowAttenuation * lightData.distanceAttenuation;
                color.xyz *= max(shadow, _shadowScale);

                if (colorMask.b > 0.5) {
                    color.xyz *= _specularScaleB;
                }

                if (colorMask.g > 0.5) {
                    half3 worldPos = i.positionWS;
                    half3 cameraPos = _WorldSpaceCameraPos.xyz;
                    half3 viewDir = normalize(cameraPos - worldPos);
                    half3 worldNormal = i.normalWS;
                    half3 lightDir = lightData.direction;
                    float3 reflectDir = normalize(mul(worldNormal , 2) - lightDir);
                    // Phong 模型公式高光反射计算
                    float3 _speColor = _SpecialColor.xyz;
                    float3 specular = lightData.color.rgb * _speColor * pow(max(0,dot(reflectDir,viewDir)), _Gloss);

                    // half3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;
                    half diffuse = saturate(dot(lightDir, worldNormal)) * _DiffuseStrengh;
                    diffuse = max(diffuse, _MinDiffuse);
                    
                    color.xyz = diffuse * color.xyz + specular * _SpecialStrengh;
                }

                return color;
                
            }
            ENDHLSL
        }

        Pass {
            Name "Outline"
            Tags {"LightMode"="Outline"}
            Cull Front
            ZTest Less
		    ZWrite On

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            v2f vert (appdata v)
            {
                v2f o;
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                float3 dir = TransformObjectToWorldNormal(v.normal);
                float3 dir2 = v.normal;
                float D = dot(dir, dir2);
                dir = dir*sign(D);
                dir = dir*_Factor + dir2*(1-_Factor);
                v.positionOS.xyz += dir*_Outline;
                o.positionHCS = TransformObjectToHClip(v.positionOS.xyz);
                return o;
            }

            half4 frag (v2f i) : SV_Target
            {
                // sample the texture
                half4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv);
                if (color.a < 0.5) discard;
                
                half4 c = _OutlineColor;
			    return c;
            }
            ENDHLSL
        }

        Pass {
            Name "ShadowCaster"
            Tags
            {
                "LightMode" = "ShadowCaster"
            }

            // -------------------------------------
            // Render State Commands
            ZWrite On
            ZTest LEqual
            Cull Back

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex vert
            #pragma fragment frag

            v2f vert (appdata v)
            {
                v2f o;
                o.positionHCS = TransformObjectToHClip(v.positionOS.xyz);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            half4 frag (v2f i) : SV_Target
            {
                half4 color = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv);
                if (color.a < 0.5) discard;
                return 1;
            }
            
            ENDHLSL
        }
    }
}