// Upgrade NOTE: replaced '_World2Object' with 'unity_WorldToObject'

// Upgrade NOTE: replaced '_World2Object' with 'unity_WorldToObject'

Shader "LXC/09 Specular Fragment BlinnPhong"
{
	Properties{
		_Diffuse("Diffuse Color",Color) = (1,1,1,1)
		_Gloss("Gloss",Range(8,200)) = 10
		_Specular("Specular Color",Color)=(1,1,1,1)
	}
		SubShader
	{
		Pass{
		Tags{ "LightMode" = "ForwardBase" }
		CGPROGRAM
#include "Lighting.cginc"
#pragma vertex vert		
#pragma fragment frag
		fixed4 _Diffuse;
		half _Gloss;
		fixed4 _Specular;

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

	struct v2f {
		float4 position:SV_POSITION;
		float3 worldNormal : TEXCOLOR0;
		float4 worldVertex : TEXCOLOR1;
	};

	v2f vert(a2v v) {
		v2f f;
		f.position = UnityObjectToClipPos(v.vertex);

		//f.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);
		f.worldNormal = UnityObjectToWorldNormal(v.normal);

		f.worldVertex = mul(v.vertex, unity_WorldToObject);
		return f;
	}


	fixed4 frag(v2f f) :SV_Target{	
		fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.rgb;
		fixed3 normalDir = normalize(f.worldNormal);

		//fixed3 lightDir = normalize(_WorldSpaceLightPos0.xyz);
		fixed3 lightDir = normalize(WorldSpaceLightDir(f.worldVertex));

		fixed3 diffuse = _LightColor0.rgb * max(dot(normalDir, lightDir), 0)*_Diffuse.rgb;
		//fixed3 reflectDir = normalize(reflect(-lightDir, normalDir));		//下方為BlinnPhong寫法	
		//fixed3 viewDir = normalize(_WorldSpaceCameraPos.xyz - f.worldVertex);
		fixed3 viewDir = normalize(UnityWorldSpaceViewDir(f.worldVertex).xyz);

		//獲取平行光和視野方向的平分線
		fixed3 halfDir = normalize(viewDir + lightDir);	//兩個向量相加單位化就是平分線
		fixed3 specular = _LightColor0.rgb * pow(max(dot(normalDir, halfDir), 0), _Gloss) * _Specular.rgb;
		fixed3 tempColor = diffuse + ambient + specular;
		return fixed4(tempColor,1);
	}
		ENDCG
	}
	}
		Fallback "Diffuse"
}