diffuse_ambient_lightprobe 1차 추가

Author: SamYeonKim

Assets/Tutorials/diffuse_ambient_lightprobe/diffuse_ambient_lightprobe.mat

@@ -39,7 +39,7 @@ Material:
         m_Scale: {x: 1, y: 1}
         m_Offset: {x: 0, y: 0}
     - _MainTex:
-        m_Texture: {fileID: 2800000, guid: ddee01e2719a1394d95c1f33ec367a3a, type: 3}
+        m_Texture: {fileID: 10910, guid: 0000000000000000f000000000000000, type: 0}
         m_Scale: {x: 1, y: 1}
         m_Offset: {x: 0, y: 0}
     - _MetallicGlossMap:

Assets/Tutorials/diffuse_ambient_lightprobe/diffuse_ambient_lightprobe.md

@@ -0,0 +1,70 @@
+# Abstract
+
+diffuse lighting, ambient, light probe 를 적용해보자
+
+# Shader
+
+```c
+Shader "UnityShaderTutorial/diffuse_ambient_lightprobe" {
+    Properties
+    {
+        [NoScaleOffset] _MainTex ("Texture", 2D) = "white" {}
+    }
+    SubShader
+    {
+        Pass
+        {
+            Tags {"LightMode"="ForwardBase"}
+        
+            CGPROGRAM
+            #pragma vertex vert
+            #pragma fragment frag
+            #include "UnityCG.cginc"
+            #include "UnityLightingCommon.cginc"
+
+            struct v2f
+            {
+                float2 uv : TEXCOORD0;
+                fixed4 diff : COLOR0;
+                float4 vertex : SV_POSITION;
+            };
+
+            v2f vert (appdata_base v)
+            {
+                v2f o;
+                o.vertex = UnityObjectToClipPos(v.vertex);
+                o.uv = v.texcoord;
+                half3 worldNormal = UnityObjectToWorldNormal(v.normal);
+                half nl = max(0, dot(worldNormal, _WorldSpaceLightPos0.xyz));
+                o.diff = nl * _LightColor0;
+
+                // the only difference from previous shader:
+                // in addition to the diffuse lighting from the main light,
+                // add illumination from ambient or light probes
+                // ShadeSH9 function from UnityCG.cginc evaluates it,
+                // using world space normal
+                o.diff.rgb += ShadeSH9(half4(worldNormal,1));
+                return o;
+            }
+            
+            sampler2D _MainTex;
+
+            fixed4 frag (v2f i) : SV_Target
+            {
+                fixed4 col = tex2D(_MainTex, i.uv);
+                col *= i.diff;
+                return col;
+            }
+            ENDCG
+        }
+    }
+}
+```
+
+# Description
+
+이전챕터인 [diffuse](???) 와의 차이는 `환경광 (AmbientLight), 라이트프로브` 까지 적용된다는 점이다.
+
+```
+o.diff.rgb += ShadeSH9(half4(worldNormal,1));
+```

Assets/Tutorials/diffuse_ambient_lightprobe/diffuse_ambient_lightprobe.md.meta

@@ -16,6 +16,49 @@ Shader "UnityShaderTutorial/diffuse_ambient_lightprobe" {
             #include "UnityCG.cginc"
             #include "UnityLightingCommon.cginc"
 
+			// normal should be normalized, w=1.0
+half3 SHEvalLinearL0L1s (half4 normal)
+{
+    half3 x;
+
+    // Linear (L1) + constant (L0) polynomial terms
+    x.r = dot(unity_SHAr,normal);
+    x.g = dot(unity_SHAg,normal);
+    x.b = dot(unity_SHAb,normal);
+
+    return x;
+}
+
+// normal should be normalized, w=1.0
+half3 SHEvalLinearL2s (half4 normal)
+{
+    half3 x1, x2;
+    // 4 of the quadratic (L2) polynomials
+    half4 vB = normal.xyzz * normal.yzzx;
+    x1.r = dot(unity_SHBr,vB);
+    x1.g = dot(unity_SHBg,vB);
+    x1.b = dot(unity_SHBb,vB);
+
+    // Final (5th) quadratic (L2) polynomial
+    half vC = normal.x*normal.x - normal.y*normal.y;
+    x2 = unity_SHC.rgb * vC;
+
+    return x1 + x2;
+}
+
+// normal should be normalized, w=1.0
+// output in active color space
+half3 ShadeSH9s (half4 normal)
+{
+    // Linear + constant polynomial terms
+    half3 res = SHEvalLinearL0L1s (normal);
+
+    // Quadratic polynomials
+    res += SHEvalLinearL2s (normal);
+
+    return res;
+}
+
             struct v2f
             {
                 float2 uv : TEXCOORD0;
@@ -37,7 +80,7 @@ Shader "UnityShaderTutorial/diffuse_ambient_lightprobe" {
                 // add illumination from ambient or light probes
                 // ShadeSH9 function from UnityCG.cginc evaluates it,
                 // using world space normal
-                o.diff.rgb += ShadeSH9(half4(worldNormal,1));
+                o.diff.rgb += ShadeSH9s(half4(worldNormal,1));
                 return o;
             }