Help with adding displacement to my reflection shader

Hi, I am really struggling here to add displacement into my reflection shader.

Firstly here is the shader code:

Code (CSharp):

1.  
2. Shader "FX/2D Reflection"
3. {
4.     Properties
5.     {
6.         _MainTex ("Sprite Texture", 2D) = "white" {}
7.         _DispTex ("Disp Texture", 2D) = "gray" {}
8.         _Displacement ("Displacement", Range(0, 1.0)) = 0.3
9.         _Color ("Tint", Color) = (1,1,1,1)
10.         [HideInInspector] _ReflectionTex ("", 2D) = "white" {}
11.     }
12.     SubShader
13.     {
14.         Tags  { "RenderType"="Opaque" }
15.         LOD 100
16.         Pass
17.         {
18.             CGPROGRAM
19.             #pragma vertex vert
20.             #pragma fragment frag
21.             #include "UnityCG.cginc"
22.  
23.             struct appdata_t
24.             {
25.                 float2 uv : TEXCOORD0;
26.                 float4 refl : TEXCOORD1;
27.                 float4 pos : POSITION;
28.                 float4 col: COLOR;
29.             };
30.             struct v2f
31.             {
32.                 half2 uv : TEXCOORD0;
33.                 float4 refl : TEXCOORD1;
34.                 float4 pos : SV_POSITION;
35.                 fixed4 col: COLOR;
36.             };
37.             float4 _MainTex_ST;
38.             fixed4 _Color;
39.             v2f vert(appdata_t i)
40.             {
41.                 v2f o;
42.                 o.pos = UnityObjectToClipPos (i.pos);
43.                 o.uv = TRANSFORM_TEX(i.uv, _MainTex);
44.                 o.col = i.col * _Color;
45.                 o.refl = ComputeScreenPos (o.pos);
46.                 return o;
47.             }
48.             sampler2D _MainTex;
49.             sampler2D _ReflectionTex;
50.             fixed4 frag(v2f i) : SV_Target
51.             {
52.                 fixed4 tex = tex2D(_MainTex, i.uv) * i.col;
53.                 tex.rgb *= tex.a;
54.                 fixed4 refl = tex2Dproj(_ReflectionTex, UNITY_PROJ_COORD(i.refl));
55.                 return tex * refl;
56.             }
57.             ENDCG
58.         }
59.     }
60. }

Now I assume I would have have to somehow use the displacement map on the return texture from the fragment function, but I am not sure how.

I found that someone else has used a displacement map like this:

Code (CSharp):

1. half2 displacement1 = tex2D( _Displacement1Tex, i.uv.xy );
2. float2 adjusted = i.uv.xy + (displacement1.rg - .5);
3. half4 output = tex2D(_MainTex, adjusted);

But I tried to replace the _MainTex with the reflection texture as that seemed to make sense, but that didnt work at all.

Any ideas on how I can get this to work, so that I can adjust the displacement amount at runtime to create water ripples?

 

I have managed to get this to compile, but the displacement map still isnt applying at all... Can anyone see why this might be?

Code (CSharp):

1. Shader "FX/2D Reflection"
2. {
3.     Properties
4.     {
5.         _MainTex ("Sprite Texture", 2D) = "white" {}
6.         _DispTex ("Disp Texture", 2D) = "gray" {}
7.         _Displacement ("Displacement", Range(0, 1.0)) = 0.3
8.         _Color ("Tint", Color) = (1,1,1,1)
9.         [HideInInspector] _ReflectionTex ("", 2D) = "white" {}
10.     }
11.     SubShader
12.     {
13.         Tags  { "RenderType"="Opaque" }
14.         LOD 100
15.         Pass
16.         {
17.             CGPROGRAM
18.             #pragma vertex vert
19.             #pragma fragment frag
20.             #include "UnityCG.cginc"
21.             struct appdata_t
22.             {
23.                 float2 uv : TEXCOORD0;
24.                 float4 refl : TEXCOORD1;
25.                 float4 pos : POSITION;
26.                 float4 col: COLOR;
27.             };
28.             struct v2f
29.             {
30.                 half2 uv : TEXCOORD0;
31.                 float4 refl : TEXCOORD1;
32.                 float4 pos : SV_POSITION;
33.                 fixed4 col: COLOR;
34.             };
35.             float4 _MainTex_ST;
36.             fixed4 _Color;
37.             v2f vert(appdata_t i)
38.             {
39.                 v2f o;
40.                 o.pos = UnityObjectToClipPos (i.pos);
41.                 o.uv = TRANSFORM_TEX(i.uv, _MainTex);
42.                 o.col = i.col * _Color;
43.                 o.refl = ComputeScreenPos (o.pos);
44.                 return o;
45.             }
46.             sampler2D _MainTex;
47.             sampler2D _ReflectionTex;
48.             sampler2D _DispTex;
49.             float _Displacement;
50.             fixed4 frag(v2f i) : SV_Target
51.             {
52.                 fixed4 tex = tex2D(_MainTex, i.uv) * i.col;
53.                 tex.rgb *= tex.a;
54.  
55.                 fixed4 refl = tex2Dproj(_ReflectionTex, UNITY_PROJ_COORD(i.refl));
56.                
57.                 half2 displacement1 = tex2D( _DispTex, i.uv.xy *_Displacement);
58.                 float2 adjusted = i.uv.xy + (displacement1.rg - .5);
59.  
60.                 half4 output = tex2D(_MainTex, adjusted);
61.                 return output * refl * tex;
62.             }
63.             ENDCG
64.         }
65.     }
66. }

 

that code works here.. can see the effect.. (although it also offset the whole main texture..)


i have some old test here that does similar thing,
https://unitycoder.com/blog/2012/02/26/water-splash-screen-effect-shader/

 

Uh... hang on, the code works?

Ok, I'm seriously confused now becuase it doesnt for me!!

 

I still cannot get this to work, when I place the shader material on a plane, I get the reflection but no displacement is applying. Can anyone see if I have done something obviously wrong??

 

You have a ton of casts and mismatched types, which could be why it compiles fine on some gpus but not on yours.

Code (csharp):

1. tex.rgb *= tex.a

Even stuff like this which seems super tame and CG is "supposed" to handle I've been bitten by on certain mobile gpus. Much safer to be explicit and do:

Code (csharp):

1. tex.rgb *= tex.aaa

and...

Code (csharp):

1. float2 adjusted = i.uv.xy + (displacement1.rg - 0.5.xx);

Plus you're all over the place between floats, halves, fixed, etc.

 

Thanks for the help, to be honest i'm not surprised its a mess as I am really making this up as I go along. I have tried to learn how to write shader code but I only seem to find info on the basics, and this kind of stuff ends up like some form of dark magic!

Basically, I took the surface reflection shader from the wiki here: http://wiki.unity3d.com/index.php/SurfaceReflection#Script_-_SurfaceReflection.cs

That works fine, but it just looks like a mirror, and I need to get some form of ripple or displacement, so I was taking the info found in this thread here: https://forums.tigsource.com/index.php?topic=40539.20

I was trying to get that into the reflection shader, but nothing I try seems to work.

I think I may have to give up on this and pay someone to write one as this is beyond my level of understanding and comprehension.