Add text decal shader

Assets/Shaders/TextDecal.cginc

@@ -0,0 +1,41 @@
+float4 _DecalColor;
+float _Weight;
+
+float4 _OutlineColor;
+float _OutlineWidth;
+
+void surf(DecalSurfaceInput IN, inout SurfaceOutput o) {
+    float4 color = _DecalColor;
+
+    float bias = _Cutoff - (_Weight / 4);
+    #ifdef DECAL_OUTLINE
+        bias -= _OutlineWidth * 0.25;
+    #endif
+    float dist = bias - tex2D(_Decal, IN.uv_decal).r;
+    float ddist = SDFdDist(dist);
+    
+    #ifdef DECAL_OUTLINE
+        float outlineDist = (_OutlineWidth * 0.5) + dist;
+        float outline = SDFAA(outlineDist, -ddist);
+        color = lerp(color, _OutlineColor, outline);
+    #endif
+    
+    o.Albedo = UnderwaterFog(IN.worldPosition, color).rgb;
+    o.Alpha =  _DecalOpacity * SDFAA(dist, ddist);
+
+    #ifdef DECAL_BASE_NORMAL
+        float3 normal = IN.normal;
+        float wearFactor = 1 - normal.z;
+        float wearFactorAlpha = saturate(_EdgeWearStrength * wearFactor);
+        o.Alpha *= saturate(1 + _EdgeWearOffset - saturate(_EdgeWearStrength * wearFactor));
+    #endif
+
+    #ifdef DECAL_SPECMAP
+        float4 specular = tex2D(_SpecMap, IN.uv_specmap);
+        o.Gloss = specular.r;
+        o.Specular = _Shininess;
+    #endif
+
+    half rim = 1.0 - saturate(dot(normalize(IN.viewDir), o.Normal));
+    o.Emission = (_RimColor.rgb * pow(rim, _RimFalloff)) * _RimColor.a;
+}