How to combine clip() with unity SSAO

Hi there,
I'm trying to use the unity SSAO shader in combination with a surface shader that uses clip() to discard pixels.
Unfortunately the SSAO shader ignores the clip and renders as if the full quad was drawn.
I'm hoping that a certain tags combination will convince the unity pipeline that my shader wants to be treated specially.
I tried copying stuff from the unity Transparent/Cutout/Diffuse shader, but that uses a fixed cutoff value.

I've attached a sample scene and here is the source :

Code (csharp):

1. Shader "Clip Shader" {
2.     Properties {
3.         _MainTex ("Base (RGB)", 2D) = "white" {}
4.     }
5.     SubShader {
6.         Tags {"IgnoreProjector"="True" "RenderType"="TransparentCutout"}
7.         LOD 200
8.         Cull off
9.        
10.         CGPROGRAM
11.         #pragma surface surf Lambert
12.        
13.         sampler2D _MainTex;
14.  
15.         struct Input {
16.             float2 uv_MainTex;
17.             float3 worldPos;
18.         };
19.  
20.         void surf (Input IN, inout SurfaceOutput o) {
21.             clip (-length(IN.worldPos) + 1);
22.             half4 c = tex2D (_MainTex, IN.uv_MainTex);
23.             o.Albedo = c.rgb;
24.             o.Alpha = c.a;
25.         }
26.         ENDCG
27.     }
28.     FallBack "Transparent/Cutout/Diffuse"
29. }

 

Doesn't the SSAO shader use a composite upsample shader/material to blit the result to the screen?

If so, couldn't you just modify that compositing shader and do any masking you want in there?

I haven't looked at how SSAO works, but that's the bit I'd be hunting around for if I wanted to apple a texture mask to the results.

 

No, its more fundamental than masking the output.
The textured geometry that is clipped away, changes the form of the geometry on which the ssao should be performed.
So actually the question isn't really whether the ssao shader works with clipped pixels, but whether the rendering of the depth+normals take the clip operations into account.

I did some testing and unity's Transparent/Cutout/Diffuse shader works fine with ssao.
But as soon as I change the output of the alpha component from just a sampled texture to something depending on worldspace coordinates, the effect breaks.
The render output is what I clip, but the ssao is still derived from the texture alpha.
As you can see below, the ssao output of both shaders is identical.

Code (csharp):

1. void surf (Input IN, inout SurfaceOutput o) {
2.     half4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
3.     o.Albedo = c.rgb;
4.     o.Alpha = c.a;
5. }

Renders :

Code (csharp):

1. void surf (Input IN, inout SurfaceOutput o) {
2.     half4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
3.     o.Albedo = c.rgb;
4.     o.Alpha = -length(IN.worldPos) + 1 + 3.5;
5. }

Renders :

 

Actually, its quite logical.
Unity uses an override shader to render the depth+ normal texture.
There's no way that this shader is going to know what I'm up to with my clipping.
So the only way I see around this is to render my own depth+ normals.
Is there any docs or code around to help me get started with this ?

 

Mebbeh:

http://www.ogre3d.org/forums/viewtopic.php?f=8&t=44772

 

Ah great, I totally forgot to check the builtin shaders archive.
This means I don't have to reverse-engineer the encoding etc.
Thanks a lot !

 

@danial-Brauer: Sorry for reopening an old thread but is this still somehow possible in Unity 5.5? The shader seems to be called "Hidden/Internal-DepthNormalsTexture" now but I can't figure out how to add a custom version of this shader to unity.

 

Same question as above. I can't figure this out how to add my custom shader with extra passes to GraphicsSettings so Unity actually uses it in 5.5 either.

 

You need to enable the debug mode in Unity in order to see the missing buttons in the GraphicsSettings.