Shader "_MyShader/6_Light/0_ForwardRendering"
{
Properties
{
_DiffuseColor ("DiffuseColor",COLOR) =(1,1,1,1)
_SpecularColor ("SpecularColor",COLOR) =(1,1,1,1)
_SpecularRange ("SpecularRange",Range(5,100)) = 20
}
SubShader
{
Pass
{
Tags{"LightMode" = "ForwardBase"}
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_fwdbase

        #include "Lighting.cginc"


        fixed4 _DiffuseColor;
        fixed4 _SpecularColor;
        float _SpecularRange;

        struct a2v {
            float4 vertex:POSITION;
            float3 normal:NORMAL;
        };

        struct v2f{
            float4 pos:SV_POSITION;
            fixed3 worldNormalDir:POSITION1;
            fixed3 worldLightDir:POSITION2;
            half3 reflectDir:POSITION3;
            fixed3 worldViewDir:POSITION4;
            //Blinn-Phong
            fixed3 blinn_Phong_Dir:POSITION5;
        };

        v2f vert(a2v v){
            v2f o;
            o.pos=mul(UNITY_MATRIX_MVP,v.vertex);

            o.worldLightDir = normalize(_WorldSpaceLightPos0);
            o.worldNormalDir = normalize(mul(v.normal,(float3x3)_World2Object));

            //计算反射向量
            o.reflectDir = normalize(reflect(-o.worldLightDir,o.worldNormalDir));
            //计算视角向量
            o.worldViewDir = normalize(_WorldSpaceCameraPos - mul(_Object2World,v.vertex));

            //Blinn-Phong
            o.blinn_Phong_Dir = normalize(o.worldLightDir + o.worldViewDir);

            return o;
        }

        fixed4 frag(v2f i):SV_Target{
            //漫反射阶段
            fixed3 ambientColor=UNITY_LIGHTMODEL_AMBIENT;

            fixed3 diffuseColor = _LightColor0 * _DiffuseColor*saturate(dot(i.worldNormalDir,i.worldLightDir));

            //高光阶段
            fixed3 specularColor = _LightColor0 * _SpecularColor * pow(saturate(dot(i.reflectDir,i.worldViewDir)),_SpecularRange);
            //Blinn-Phong光照
            //fixed3 specularColor = _LightColor0 * _SpecularColor * pow(saturate(dot(i.worldNormalDir,i.blinn_Phong_Dir)),_SpecularRange);
            
            fixed atten = 1.0;

            fixed4 col = fixed4(ambientColor + (diffuseColor + specularColor) * atten,1);
            return col;
        }

        
        ENDCG
    }


    Pass
    {
        Tags{"LightMode" = "ForwardAdd"}
        Blend One One

        CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        #pragma multi_compile_fwdadd
        
        #include "Lighting.cginc"
        #include "AutoLight.cginc"
        #include "UnityPBSLighting.cginc"


        fixed4 _DiffuseColor;
        fixed4 _SpecularColor;
        float _SpecularRange;

        struct a2v {
            float4 vertex:POSITION;
            float3 normal:NORMAL;
        };

        struct v2f{
            float4 pos:SV_POSITION;
            fixed3 worldNormalDir:POSITION1;
            fixed3 worldLightDir:POSITION2;
            half3 reflectDir:POSITION3;
            fixed3 worldViewDir:POSITION4;
            //Blinn-Phong
            fixed3 blinn_Phong_Dir:POSITION5;
            float4 worldPos:POSITION6;
        };

        v2f vert(a2v v){
            v2f o;
            o.pos=mul(UNITY_MATRIX_MVP,v.vertex);

            o.worldPos = mul(_Object2World,v.vertex);
            
        #ifdef USING_DIRECTIONAL_LIGHT
            o.worldLightDir = normalize(_WorldSpaceLightPos0);
        #else
            o.worldLightDir = normalize(_WorldSpaceLightPos0 - o.worldPos);
        #endif

            o.worldNormalDir = normalize(mul(v.normal,(float3x3)_World2Object));

            //计算反射向量
            o.reflectDir = normalize(reflect(-o.worldLightDir,o.worldNormalDir));
            //计算视角向量
            o.worldViewDir = normalize(_WorldSpaceCameraPos - mul(_Object2World,v.vertex));

            //Blinn-Phong
            o.blinn_Phong_Dir = normalize(o.worldLightDir + o.worldViewDir);

            return o;
        }

        fixed4 frag(v2f i):SV_Target{
            //漫反射阶段
            //fixed3 ambientColor=UNITY_LIGHTMODEL_AMBIENT;

            fixed3 diffuseColor = _LightColor0 * _DiffuseColor*saturate(dot(i.worldNormalDir,i.worldLightDir));

            //高光阶段
            fixed3 specularColor = _LightColor0 * _SpecularColor * pow(saturate(dot(i.reflectDir,i.worldViewDir)),_SpecularRange);
            //Blinn-Phong光照
            //fixed3 specularColor = _LightColor0 * _SpecularColor * pow(saturate(dot(i.worldNormalDir,i.blinn_Phong_Dir)),_SpecularRange);
        #ifdef USING_DIRECTIONAL_LIGHT
            fixed atten = 1.0;
        #else
            UNITY_LIGHT_ATTENUATION(atten, 0, i.worldPos.xyz)
        #endif

            fixed4 col = fixed4((diffuseColor + specularColor) * atten,1);
            return col;
        }

        
        ENDCG
    }

}
FallBack "VertexLit"

}