Compute world-space normal in programmable portion of the shader

Assets/Shaders/DecalFeatureBumped.shader

@@ -2,11 +2,18 @@ Shader "ConformalDecals/Feature/Bumped"
 {
     Properties
     {
+        [Header(Texture Maps)]
 		_Decal("Decal Texture", 2D) = "gray" {}
-		_DecalBumpMap("Decal Normal Map", 2D) = "bump" {}
+		_DecalBumpMap("Decal Bump Map", 2D) = "bump" {}
 		
 	    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
 		_Opacity("_Opacity", Range(0,1) ) = 1
+		
+		[Header(Effects)]
+		[PerRendererData]_Opacity("_Opacity", Range(0,1) ) = 1
+			[PerRendererData]_RimFalloff("_RimFalloff", Range(0.01,5) ) = 0.1
+			[PerRendererData]_RimColor("_RimColor", Color) = (0,0,0,0)
+			[PerRendererData]_UnderwaterFogFactor ("Underwater Fog Factor", Range(0,1)) = 0
     }
     SubShader
     {
@@ -35,9 +42,11 @@ Shader "ConformalDecals/Feature/Bumped"
 
             sampler2D _Decal;
             sampler2D _DecalBumpMap;
-            
+  
             float _Cutoff;
             float _Opacity;
+            float _RimFalloff;
+            float4 _RimColor;
             
             void surf (DecalSurfaceInput IN, inout SurfaceOutput o)
             {
@@ -52,11 +61,16 @@ Shader "ConformalDecals/Feature/Bumped"
 
                 float4 color = tex2D(_Decal, projUV);
                 float3 normal = UnpackNormal(tex2D(_DecalBumpMap, projUV));
+                half rim = 1.0 - saturate(dot (normalize(IN.viewDir), normal));
+                float3 emission = (_RimColor.rgb * pow(rim, _RimFalloff)) * _RimColor.a;
+
+                // clip alpha
                 clip(color.a - _Cutoff);
                 
-                o.Normal = normal;
-                o.Albedo = color.rgb;
+                o.Albedo = UnderwaterFog(IN.worldPosition, color).rgb;
                 o.Alpha = color.a * _Opacity;
+                o.Emission = emission;
+                o.Normal = DECAL_ORIENT_NORMAL(normal, IN);
             }
 
             ENDCG
@@ -85,6 +99,8 @@ Shader "ConformalDecals/Feature/Bumped"
             
             float _Cutoff;
             float _Opacity;
+            float _RimFalloff;
+            float4 _RimColor;
             
             void surf (DecalSurfaceInput IN, inout SurfaceOutput o)
             {
@@ -99,11 +115,16 @@ Shader "ConformalDecals/Feature/Bumped"
 
                 float4 color = tex2D(_Decal, projUV);
                 float3 normal = UnpackNormal(tex2D(_DecalBumpMap, projUV));
+                half rim = 1.0 - saturate(dot (normalize(IN.viewDir), normal));
+                float3 emission = (_RimColor.rgb * pow(rim, _RimFalloff)) * _RimColor.a;
+
+                // clip alpha
                 clip(color.a - _Cutoff);
                 
-                o.Normal = normal;
-                o.Albedo = color.rgb;
+                o.Albedo = UnderwaterFog(IN.worldPosition, color).rgb;
                 o.Alpha = color.a * _Opacity;
+                o.Emission = emission;
+                o.Normal = DECAL_ORIENT_NORMAL(normal, IN);
             }
 
             ENDCG

Assets/Shaders/DecalsCommon.cginc

@@ -1,6 +1,17 @@
 #ifndef DECALS_COMMON_INCLUDED
 #define DECALS_COMMON_INCLUDED
 
+inline fixed3 OrientNormal(float3 normal, float4 tSpace0, float4 tSpace1, float4 tSpace2) {
+    float3 WorldNormal;
+    WorldNormal.x = dot(tSpace0.xyz, normal);
+    WorldNormal.y = dot(tSpace1.xyz, normal);
+    WorldNormal.z = dot(tSpace2.xyz, normal);
+    WorldNormal = normalize(WorldNormal);
+    return WorldNormal;
+} 
+
+#define DECAL_ORIENT_NORMAL(normal, IN)  OrientNormal(normal, IN.tSpace0, IN.tSpace1, IN.tSpace2) 
+
 struct DecalSurfaceInput
 {
     float4 uv_decal;
@@ -9,6 +20,11 @@ struct DecalSurfaceInput
     #endif //DECAL_BASE_NORMAL
     float3 normal;
     float3 viewDir;
+    float3 worldPosition;
+    
+    float4 tSpace0;
+    float4 tSpace1;
+    float4 tSpace2;
 };
 
 struct appdata_decal
@@ -140,6 +156,10 @@ fixed4 frag_forward(v2f IN) : SV_Target
     #endif
     i.normal = IN.normal;
     i.viewDir = viewDir;
+    i.worldPosition = worldPosition;
+    i.tSpace0 = IN.tSpace0;
+    i.tSpace1 = IN.tSpace1;
+    i.tSpace2 = IN.tSpace2;
     
     // initialize surface output
     o.Albedo = 0.0;
@@ -155,14 +175,6 @@ fixed4 frag_forward(v2f IN) : SV_Target
     // compute lighting & shadowing factor
     UNITY_LIGHT_ATTENUATION(atten, IN, worldPosition)
     
-    // compute world normal
-    float3 WorldNormal;
-    WorldNormal.x = dot(_unity_tbn_0, o.Normal);
-    WorldNormal.y = dot(_unity_tbn_1, o.Normal);
-    WorldNormal.z = dot(_unity_tbn_2, o.Normal);
-    WorldNormal = normalize(WorldNormal);
-    o.Normal = WorldNormal;
-    
     //KSP lighting function
     c += LightingBlinnPhongSmooth(o, lightDir, viewDir, atten);