[Help] Fade/Distortion Image effect

Okay, I have tried everything I can think of but I just can't get this effect to work.

Basically what I intend to do is recreate this effect on my camera:
http://glslsandbox.com/e#23666.2

I've been using the built in motion blur Image effect as it makes use of the previous screen that was rendered, and so far I've been partially successful.
My problem is getting the previous rendered screen to slowly move to the side overtime while it fades to black.
It won't budge no matter what I do.

Here's both my .cs and .shader files:

AfterImage.cs

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [ExecuteInEditMode]
5. public class AfterImage : MonoBehaviour
6. {
7.     public Shader shader;
8.     private Material material
9.     {
10.         get
11.         {
12.             if (m_material == null)
13.                 m_material = new Material(shader);
14.             return m_material;
15.         }
16.     }
17.     private Material m_material = null;
18.     private RenderTexture rTexture = null;
19.     public float alpha = 0.1f;
20.  
21.     void OnRenderImage(RenderTexture source, RenderTexture dest)
22.     {
23.         if (rTexture == null || rTexture.width != rTexture.width || rTexture.height != rTexture.height)
24.         {
25.             DestroyImmediate(rTexture);
26.             rTexture = new RenderTexture(source.width, source.height, 0);
27.             rTexture.hideFlags = HideFlags.HideAndDontSave;
28.             Graphics.Blit(source, rTexture);
29.         }
30.  
31.         material.SetFloat("_alpha", alpha);
32.         Graphics.Blit(source, rTexture, material);
33.         Graphics.Blit(rTexture, dest);
34.     }
35. }
36.  

AfterImage.shader

Code (CSharp):

1. Shader "Custom/AfterImage"
2. {
3.     Properties
4.     {
5.         _MainTex ("Main Texture", 2D) = "white" {}  
6.         _alpha ("Alpha", float) = 0.0
7.     }
8.     SubShader
9.     {
10.         Pass
11.         {
12.             Blend SrcAlpha OneMinusSrcAlpha              
13.             CGPROGRAM
14.            
15.             #pragma vertex vert_img
16.             #pragma fragment frag
17.             #include "UnityCG.cginc"
18.             #pragma target 3.0
19.  
20.             sampler2D _MainTex;
21.             uniform float _alpha;
22.  
23.             float4 frag(v2f_img inpu): COLOR
24.             {              
25.                 float2 uv = inpu.uv * 1.01;
26.                 float4 newcol = tex2D(_MainTex, uv);
27.                 newcol.a = _alpha;
28.                 return newcol;
29.             }
30.             ENDCG
31.         }
32.  
33.  
34.     }
35.     FallBack "Diffuse"
36. }
37.  

Any help would be greatly appreciated :^)

 

polite bump
still haven't found a way around this :c

 

I didn't test, i'm gonna just throw ideas to (hopefully) help you out.

When you are sampling the image using tex2D you can scroll the uv in any direction, for example:

Code (csharp):

1. float2 uv = inpu.uv  + float2(0.1, 0.1);

This is blend the new image in a new position, change the 0.1 values yourself to see how it changes. This comes with a problem though, the effect will work but not exactly as you expect, because what you really want to do is to move and darken then previous image and your current shader is only doing something in the new frame.

The way to correctly do this is to save the result in a rendertexture and reuse it as is in the new frame as texture input, that way you could sample the previous frame and do whatever you want with it inside the shader.

[edit] looking more carefully into your csharp script you are already saving the previous frame in a render texture so now you only need to pass it to the shader as if it were a regular texture.

 

Hello again,

so after a lot of thought I was able to come up with something pretty close to what I intended.

I'll leave the code below, it might help somebody down the road:

AfterImage.shader

Code (CSharp):

1. Shader "Custom/AfterImage"
2. {
3.     Properties
4.     {
5.         _MainTex ("Albedo (RGB)", 2D) = "white" {}
6.         _BackBuffer ("Albedo (RGB)", 2D) = "black" {}    
7.         _Distance ("_Distance", float) = 0.02
8.         _Alpha ("_Alpha", float) = 0.8
9.         _Color ("_Color", Color) = (0.0,0.0,0.0,0.0)
10.     }
11.     SubShader
12.     {        
13.         Pass
14.         {
15.             Blend SrcAlpha OneMinusSrcAlpha
16.             CGPROGRAM
17.             #pragma vertex vert_img
18.             #pragma fragment frag
19.             #include "UnityCG.cginc"
20.  
21.             sampler2D _MainTex;
22.             sampler2D _BackBuffer;
23.  
24.             uniform float _Distance;
25.             uniform float _Alpha;
26.             uniform float4 _Color;
27.  
28.             fixed4 frag(v2f_img v2f) : COLOR
29.             {
30.                 fixed4 col = tex2D(_BackBuffer, v2f.uv + float2(_Distance, 0.0));
31.                 col.rgb *= _Color.rgb;    
32.                 fixed4 main = tex2D(_MainTex, v2f.uv);
33.                 col.a = _Alpha;
34.                 return col - main;
35.             }
36.  
37.             ENDCG
38.         }
39.      
40.     }
41.     FallBack "Diffuse"
42. }
43.  

AfterImage.cs

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [ExecuteInEditMode]
5. public class AfterImage : MonoBehaviour
6. {
7.     public Shader shader;
8.     private Material m_mat = null;
9.     private Material mat { get {
10.         if(m_mat == null)
11.             m_mat = new Material(shader);
12.         return m_mat;
13.     }
14.     }
15.     private RenderTexture _BackBuffer;
16.     public float _Distance = 0.05f;
17.     public float _Alpha = 0.8f;
18.     public Color _Color;
19.  
20.     void OnRenderImage(RenderTexture source, RenderTexture destination)
21.     {
22.         if(_BackBuffer == null)
23.         {
24.             _BackBuffer = new RenderTexture(source.width, source.height, 0, RenderTextureFormat.ARGB32);
25.             _BackBuffer.filterMode = FilterMode.Point;
26.             _BackBuffer.antiAliasing = 2;
27.         }
28.         mat.SetFloat("_Distance", _Distance);
29.         mat.SetFloat("_Alpha", _Alpha);
30.         mat.SetColor("_Color", _Color);
31.         Graphics.Blit(source, destination, mat);
32.         Graphics.Blit(destination, _BackBuffer);
33.         mat.SetTexture("_BackBuffer", _BackBuffer);
34.     }
35. }
36.