Enable multi-pass forward rendering

Assets/Shaders/DecalFeatureBumped.shader

@@ -22,8 +22,8 @@ Shader "ConformalDecals/Feature/Bumped"
      		Blend SrcAlpha OneMinusSrcAlpha
 
             CGPROGRAM
-            #pragma vertex vert_forward_base
-            #pragma fragment frag_forward_base
+            #pragma vertex vert_forward
+            #pragma fragment frag_forward
 
             #pragma multi_compile_fwdbase nolightmap nodirlightmap nodynlightmap
             
@@ -62,6 +62,53 @@ Shader "ConformalDecals/Feature/Bumped"
             ENDCG
         } 
         
+        Pass
+        {
+            Name "FORWARD"
+       		Tags { "LightMode" = "ForwardAdd" }
+     		Blend One One
+
+            CGPROGRAM
+            #pragma vertex vert_forward
+            #pragma fragment frag_forward
+
+            #pragma multi_compile_fwdadd nolightmap nodirlightmap nodynlightmap
+            
+            #include "UnityCG.cginc"
+            #include "Lighting.cginc"
+            #include "AutoLight.cginc"
+            #include "LightingKSP.cginc"
+            #include "DecalsCommon.cginc"
+
+            sampler2D _Decal;
+            sampler2D _DecalBumpMap;
+            
+            float _Cutoff;
+            float _Opacity;
+            
+            void surf (DecalSurfaceInput IN, inout SurfaceOutput o)
+            {
+                fixed4 projUV = UNITY_PROJ_COORD(IN.uv_decal);
+
+                // since I cant easily affect the clamping mode in KSP, do it here
+                clip(projUV.xyz);
+                clip(1-projUV.xyz);
+                
+                // clip backsides
+                clip(dot(_DecalNormal, IN.normal));
+
+                float4 color = tex2D(_Decal, projUV);
+                float3 normal = UnpackNormal(tex2D(_DecalBumpMap, projUV));
+                //clip(color.a - _Cutoff);
+                
+                o.Normal = normal;
+                o.Albedo = color.rgb;
+                o.Alpha = color.a * _Opacity;
+            }
+
+            ENDCG
+        } 
+        
         // shadow casting support
         UsePass "Legacy Shaders/VertexLit/SHADOWCASTER"
     }

Assets/Shaders/DecalsCommon.cginc

@@ -25,14 +25,25 @@ struct v2f
     UNITY_POSITION(pos);
     float3 normal : NORMAL;
     float4 uv_decal : TEXCOORD0;
+    
     #ifdef DECAL_BASE_NORMAL
         float2 uv_base : TEXCOORD1;
     #endif //DECAL_BASE_NORMAL
+    
     float4 tSpace0 : TEXCOORD2;
     float4 tSpace1 : TEXCOORD3;
     float4 tSpace2 : TEXCOORD4;
-    fixed3 vlight : TEXCOORD5;
-    UNITY_SHADOW_COORDS(6)
+    
+    #ifdef UNITY_PASS_FORWARDBASE
+        fixed3 vlight : TEXCOORD5;
+        UNITY_SHADOW_COORDS(6)
+    #endif //UNITY_PASS_FORWARDBASE
+    
+    #ifdef UNITY_PASS_FORWARDADD
+        UNITY_LIGHTING_COORDS(5,6)
+    #endif
+
+    
 };
 
 // Projection matrix, normal, and tangent vectors
@@ -44,7 +55,7 @@ float3 _DecalTangent;
 // this must be defined in any shader using this cginc
 void surf (DecalSurfaceInput IN, inout SurfaceOutput o);
 
-v2f vert_forward_base(appdata_decal v)
+v2f vert_forward(appdata_decal v)
 {
     v2f o;
     UNITY_INITIALIZE_OUTPUT(v2f,o);
@@ -59,7 +70,6 @@ v2f vert_forward_base(appdata_decal v)
     
     float3 worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
     float3 worldNormal = UnityObjectToWorldNormal(v.normal);
-    //fixed3 worldTangent = fixed3(0,0,0);//UnityObjectToWorldDir(v.tangent.xyz);
     fixed3 worldTangent = UnityObjectToWorldDir(_DecalTangent);
     fixed3 worldBinormal = cross(worldTangent, worldNormal);
     worldTangent = cross(worldNormal, worldBinormal);
@@ -67,28 +77,32 @@ v2f vert_forward_base(appdata_decal v)
     o.tSpace1 = float4(worldTangent.y, worldBinormal.y, worldNormal.y, worldPos.y);
     o.tSpace2 = float4(worldTangent.z, worldBinormal.z, worldNormal.z, worldPos.z);
     
-    // SH/ambient light
-    #if UNITY_SHOULD_SAMPLE_SH
-        float3 shlight = ShadeSH9 (float4(worldNormal,1.0));
-        o.vlight = shlight;
-    #else
-        o.vlight = 0.0;
-    #endif // UNITY_SHOULD_SAMPLE_SH
+    // forward base pass specific lighting code
+    #ifdef UNITY_PASS_FORWARDBASE
+        // SH/ambient light
+        #if UNITY_SHOULD_SAMPLE_SH
+            float3 shlight = ShadeSH9 (float4(worldNormal,1.0));
+            o.vlight = shlight;
+        #else
+            o.vlight = 0.0;
+        #endif // UNITY_SHOULD_SAMPLE_SH
     
-    // vertex light
-    #ifdef VERTEXLIGHT_ON
-        o.vlight += Shade4PointLights (
-        unity_4LightPosX0, unity_4LightPosY0, unity_4LightPosZ0,
-        unity_LightColor[0].rgb, unity_LightColor[1].rgb, unity_LightColor[2].rgb, unity_LightColor[3].rgb,
-        unity_4LightAtten0, worldPos, worldNormal );
-    #endif // VERTEXLIGHT_ON
+        // vertex light
+        #ifdef VERTEXLIGHT_ON
+            o.vlight += Shade4PointLights (
+            unity_4LightPosX0, unity_4LightPosY0, unity_4LightPosZ0,
+            unity_LightColor[0].rgb, unity_LightColor[1].rgb, unity_LightColor[2].rgb, unity_LightColor[3].rgb,
+            unity_4LightAtten0, worldPos, worldNormal );
+        #endif // VERTEXLIGHT_ON
+    #endif // UNITY_PASS_FORWARDBASE
     
-    UNITY_TRANSFER_LIGHTING(o, 0.0); // pass shadow and, possibly, light cookie coordinates to pixel shader
+    // pass shadow and, possibly, light cookie coordinates to pixel shader
+    UNITY_TRANSFER_LIGHTING(o, 0.0);
     
     return o;
 }
 
-fixed4 frag_forward_base(v2f IN) : SV_Target
+fixed4 frag_forward(v2f IN) : SV_Target
 {
     DecalSurfaceInput i;
     SurfaceOutput o;
@@ -98,7 +112,7 @@ fixed4 frag_forward_base(v2f IN) : SV_Target
     
     float3 worldPos = float3(IN.tSpace0.w, IN.tSpace1.w, IN.tSpace2.w);
     float3 worldTan = float3(IN.tSpace0.x, IN.tSpace1.x, IN.tSpace2.x);
-
+    
     #ifndef USING_DIRECTIONAL_LIGHT
         fixed3 lightDir = normalize(UnityWorldSpaceLightDir(worldPos));
     #else
@@ -135,11 +149,19 @@ fixed4 frag_forward_base(v2f IN) : SV_Target
     worldN = normalize(worldN);
     o.Normal = worldN;
     
-    
     //KSP lighting function
     c += LightingBlinnPhongSmooth(o, lightDir, viewDir, atten);
-    c.rgb += o.Emission;
-    c.rgb += o.Albedo * IN.vlight;
+    
+    #ifdef UNITY_PASS_FORWARDBASE
+        c.rgb += o.Emission;
+        c.rgb += o.Albedo * IN.vlight;
+    #endif //UNITY_PASS_FORWARDBASE
+    
+    #ifdef UNITY_PASS_FORWARDADD
+        c.rgb *= c.a;
+        c.a = 0.0;
+    #endif
+    
     return c;
 }