Built-in shaders라고 해서, Unity 홈페이지 가면 내장된 쉐이더들의 코드를 받아볼 수 있지요.
이걸 이용하면 평소에는 막혀져 있어서 볼 수 없는 내장 쉐이더들의 코드를 볼 수 있는데,
그 동안 계속 보다 보니까… 이게 계속 변하더라고요. 다운로드 받을때마다 변해있다능.
아무래도 한참 발전하는 엔진이다보니 그럴 수 있겠죠.

근데 최근의 추세를 보니 내장된 스크립트를 이용한 쉐이더들이, 전부 CG를 이용한 surface 쉐이더로 바뀌는 중.

예를 들어 Diffuse만 봐도 이렇습니다.

=================================================================================

// Upgrade NOTE: replaced ‘PositionFog()’ with multiply of UNITY_MATRIX_MVP by position
// Upgrade NOTE: replaced ‘V2F_POS_FOG’ with ‘float4 pos : SV_POSITION’

Shader “Diffuse” {
Properties {
_Color (“Main Color”, Color) = (1,1,1,1)
_MainTex (“Base (RGB)”, 2D) = “white” {}
}

Category {
Tags { “RenderType”=“Opaque” }
LOD 200
/* Upgrade NOTE: commented out, possibly part of old style per-pixel lighting: Blend AppSrcAdd AppDstAdd */
Fog { Color [_AddFog] }

// ——————————————————————
// ARB fragment program

#warning Upgrade NOTE: SubShader commented out; uses Unity 2.x per-pixel lighting. You should rewrite shader into a Surface Shader.
/*SubShader {
  // Ambient pass
  Pass {
   Name “BASE”
   Tags {“LightMode” = “Always” /* Upgrade NOTE: changed from PixelOrNone to Always */}
   Color [_PPLAmbient]
   SetTexture [_MainTex] {constantColor [_Color] Combine texture * primary DOUBLE, texture * constant}
  }
  // Vertex lights
  Pass {
   Name “BASE”
   Tags {“LightMode” = “Vertex”}
   Lighting On
   Material {
    Diffuse [_Color]
    Emission [_PPLAmbient]
   }
   SetTexture [_MainTex] { constantColor [_Color] Combine texture * primary DOUBLE, texture * constant}
  }
  // Pixel lights
  Pass {
   Name “PPL”
   Tags { “LightMode” = “Pixel” }
CGPROGRAM
// Upgrade NOTE: excluded shader from Xbox360; has structs without semantics (struct v2f members uv,normal,lightDir)
#pragma exclude_renderers xbox360
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_builtin
#pragma fragmentoption ARB_fog_exp2
#pragma fragmentoption ARB_precision_hint_fastest
#include “UnityCG.cginc”
#include “AutoLight.cginc”

struct v2f {
float4 pos : SV_POSITION;
LIGHTING_COORDS
float2 uv;
float3 normal;
float3 lightDir;
};

uniform float4 _MainTex_ST;

v2f vert (appdata_base v)
{
v2f o;
o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
o.normal = v.normal;
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
o.lightDir = ObjSpaceLightDir( v.vertex );
TRANSFER_VERTEX_TO_FRAGMENT(o);
return o;
}

uniform sampler2D _MainTex;

float4 frag (v2f i) : COLOR
{
// The eternal tradeoff: do we normalize the normal?
//float3 normal = normalize(i.normal);
float3 normal = i.normal;

half4 texcol = tex2D( _MainTex, i.uv );

return DiffuseLight( i.lightDir, normal, texcol, LIGHT_ATTENUATION(i) );
}
ENDCG
  }
}*/

  // ——————————————————————
// Radeon 9000

#warning Upgrade NOTE: SubShader commented out because of manual shader assembly
/*SubShader {
  // Ambient pass
  Pass {
   Name “BASE”
   Tags {“LightMode” = “Always” /* Upgrade NOTE: changed from PixelOrNone to Always */}
   Color [_PPLAmbient]
   SetTexture [_MainTex] {constantColor [_Color] Combine texture * primary DOUBLE, texture * constant}
  }
  // Vertex lights
  Pass {
   Name “BASE”
   Tags {“LightMode” = “Vertex”}
   Lighting On
   Material {
    Diffuse [_Color]
    Emission [_PPLAmbient]
   }
   SetTexture [_MainTex] { constantColor [_Color] Combine texture * primary DOUBLE, texture * constant}
  }

  // Pixel lights with 0 light textures
  Pass {
   Name “PPL”
   Tags {
    “LightMode” = “Pixel”
    “LightTexCount” = “0”
   }

CGPROGRAM
// Upgrade NOTE: excluded shader from OpenGL ES 2.0 because it does not contain a surface program or both vertex and fragment programs.
#pragma exclude_renderers gles
#pragma vertex vert
#include “UnityCG.cginc”

struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float3 normal : TEXCOORD1;
float3 lightDir : TEXCOORD2;
};

uniform float4 _MainTex_ST;

v2f vert(appdata_base v)
{
v2f o;
o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
o.normal = v.normal;
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
o.lightDir = ObjSpaceLightDir( v.vertex );
return o;
}
ENDCG
   Program "" {
    SubProgram {
     Local 0, [_ModelLightColor0]
     Local 1, (0,0,0,0)

“!!ATIfs1.0
StartConstants;
CONSTANT c0 = program.local[0];
CONSTANT c1 = program.local[1];
EndConstants;

StartOutputPass;
SampleMap r0, t0.str;   # main texture
SampleMap r1, t2.str;   # normalized light dir
PassTexCoord r2, t1.str;  # normal

DOT3 r5.sat, r2, r1.2x.bias; # R5 = diffuse (N.L)

MUL r0, r0, r5;
MUL r0.rgb.2x, r0, c0;
MOV r0.a, c1;
EndPass;
"
    }
   }
   SetTexture[_MainTex] {combine texture}
   SetTexture[_CubeNormalize] {combine texture}
  }

  // Pixel lights with 1 light texture
  Pass {
   Name “PPL”
   Tags {
    “LightMode” = “Pixel”
    “LightTexCount” = “1”
   }

uniform float4 _MainTex_ST;
uniform float4x4 _SpotlightProjectionMatrix0;

struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float3 normal : TEXCOORD1;
float3 lightDir : TEXCOORD2;
float4 LightCoord0 : TEXCOORD3;
};

v2f vert(appdata_tan v)
{
v2f o;
o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
o.normal = v.normal;
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
o.lightDir = ObjSpaceLightDir( v.vertex );

o.LightCoord0 = mul(_SpotlightProjectionMatrix0, v.vertex);

return o;
}
ENDCG
   Program "” {
    SubProgram {
     Local 0, [_ModelLightColor0]
     Local 1, (0,0,0,0)

“!!ATIfs1.0
StartConstants;
CONSTANT c0 = program.local[0];
CONSTANT c1 = program.local[1];
EndConstants;

StartOutputPass;
SampleMap r0, t0.str;   # main texture
SampleMap r1, t2.str;   # normalized light dir
PassTexCoord r4, t1.str;  # normal
SampleMap r2, t3.str;   # a = attenuation

DOT3 r5.sat, r4, r1.2x.bias; # R5 = diffuse (N.L)

MUL r0, r0, r5;
MUL r0.rgb.2x, r0, c0;
MUL r0.rgb, r0, r2.a;   # attenuate
MOV r0.a, c1;
EndPass;
"
    }
   }
   SetTexture[_MainTex] {combine texture}
   SetTexture[_CubeNormalize] {combine texture}
   SetTexture[_LightTexture0] {combine texture}
  }

  // Pixel lights with 2 light textures
  Pass {
   Name “PPL”
   Tags {
    “LightMode” = “Pixel”
    “LightTexCount” = “2”
   }
CGPROGRAM
// Upgrade NOTE: excluded shader from OpenGL ES 2.0 because it does not contain a surface program or both vertex and fragment programs.
#pragma exclude_renderers gles
#pragma vertex vert
#include “UnityCG.cginc”

uniform float4 _MainTex_ST;
uniform float4x4 _SpotlightProjectionMatrix0;
uniform float4x4 _SpotlightProjectionMatrixB0;

struct v2f {
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float3 normal : TEXCOORD1;
float3 lightDir : TEXCOORD2;
float4 LightCoord0 : TEXCOORD3;
float4 LightCoordB0 : TEXCOORD4;
};

v2f vert(appdata_tan v)
{
v2f o;
o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
o.normal = v.normal;
o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
o.lightDir = ObjSpaceLightDir( v.vertex );

o.LightCoord0 = mul(_SpotlightProjectionMatrix0, v.vertex);
o.LightCoordB0 = mul(_SpotlightProjectionMatrixB0, v.vertex);

return o;
}
ENDCG
   Program "” {
    SubProgram {
     Local 0, [_ModelLightColor0]
     Local 1, (0,0,0,0)

“!!ATIfs1.0
StartConstants;
CONSTANT c0 = program.local[0];
CONSTANT c1 = program.local[1];
EndConstants;

StartOutputPass;
SampleMap r0, t0.str;   # main texture
SampleMap r1, t2.str;   # normalized light dir
PassTexCoord r4, t1.str;  # normal
SampleMap r2, t3.stq_dq;  # a = attenuation 1
SampleMap r3, t4.stq_dq;  # a = attenuation 2

DOT3 r5.sat, r4, r1.2x.bias; # R5 = diffuse (N.L)

MUL r0, r0, r5;
MUL r0.rgb.2x, r0, c0;
MUL r0.rgb, r0, r2.a;   # attenuate
MUL r0.rgb, r0, r3.a;
MOV r0.a, c1;
EndPass;
"
    }
   }
   SetTexture[_MainTex] {combine texture}
   SetTexture[_CubeNormalize] {combine texture}
   SetTexture[_LightTexture0] {combine texture}
   SetTexture[_LightTextureB0] {combine texture}
  }
}*/

// ——————————————————————
// Radeon 7000

Category {
  Material {
   Diffuse [_Color]
   Emission [_PPLAmbient]
  }
  Lighting On
  #warning Upgrade NOTE: SubShader commented out; uses Unity 2.x style fixed function per-pixel lighting. Per-pixel lighting is not supported without shaders anymore.
/*SubShader {
   // Ambient pass
   Pass {
    Name “BASE”
    Tags {“LightMode” = “Always” /* Upgrade NOTE: changed from PixelOrNone to Always */}
    Color [_PPLAmbient]
    Lighting Off
    SetTexture [_MainTex] {Combine texture * primary DOUBLE, primary * texture}
   }
   // Vertex lights
   Pass {
    Name “BASE”
    Tags {“LightMode” = “Vertex”}
    Lighting On
    Material {
     Diffuse [_Color]
     Emission [_PPLAmbient]
    }
    SetTexture [_MainTex] {Combine texture * primary DOUBLE, primary * texture}
   }
   // Pixel lights with 2 light textures
   Pass {
    Name “PPL”
    Tags {
     “LightMode” = “Pixel”
     “LightTexCount” = “2”
    }
    ColorMask RGB
    SetTexture [_LightTexture0] { combine previous * texture alpha, previous }
    SetTexture [_LightTextureB0] { combine previous * texture alpha, previous }
    SetTexture [_MainTex] { combine previous * texture DOUBLE }
   }
   // Pixel lights with 1 light texture
   Pass {
    Name “PPL”
    Tags {
     “LightMode” = “Pixel”
     “LightTexCount” = “1”
    }
    ColorMask RGB
    SetTexture [_LightTexture0] { combine previous * texture alpha, previous }
    SetTexture [_MainTex] { combine previous * texture DOUBLE }
   }
   // Pixel lights with 0 light textures
   Pass {
    Name “PPL”
    Tags {
     “LightMode” = “Pixel”
     “LightTexCount” = “0”
    }
    ColorMask RGB
    SetTexture[_MainTex] { combine previous * texture DOUBLE }
   }
  }*/
}
}

Fallback “VertexLit”, 2

}

이게 옛날에 받은 Diffuse.

이게 요즘에는 Surface 쉐이더로 바뀌었더군요.

===============================================================================
Shader “Diffuse” {
Properties {
_Color (“Main Color”, Color) = (1,1,1,1)
_MainTex (“Base (RGB)”, 2D) = “white” {}
}
SubShader {
Tags { “RenderType”=“Opaque” }
LOD 200

CGPROGRAM
#pragma surface surf Lambert

sampler2D _MainTex;
float4 _Color;

struct Input {
float2 uv_MainTex;
};

void surf (Input IN, inout SurfaceOutput o) {
half4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
o.Albedo = c.rgb;
o.Alpha = c.a;
}
ENDCG
}

Fallback “VertexLit”
}

그리고 이게 아이폰에서 더 빠르더군요.
여기서 생각할 수 있는 이전 게시물에 이은 망상 : Diffuse Fast 가 Diffuse 보다 빠르다는건 옛날 쉐이더 기준으로 써 놓은게 아니었을까. 서피스 쉐이더로 바뀌기 전에는 당근 더 무거웠을 듯. 그리고 지금은 오히려 서피스 쉐이더로 짜는게 최적화를 더 잘하게 되어 있어서 대부분의 쉐이더를 서피스 쉐이더로 바꾸는게 아닐까. 하긴 뭐 더 짜기도 쉽고.

}

Fallback “VertexLit”}

Fallback “VertexLit”
}