Help with shader to undistort webcam image

I'm quite new to shaders and I'm having some trouble implementing this Radial Undistortion example from GPU Gems. The shader uses the lens distortion coefficients generated during camera calibration to correct geometric distortion in real-time.

I'm working from the Fisheye example, which distorts a scene camera's view to simulate a fisheye lens.

The shader that I have written is as follows:

Code (csharp):

1. Shader "Custom/CameraUndistort" {
2.     Properties {
3.         _MainTex ("Base (RGB)", 2D) = "white" {}
4.     }
5.     SubShader
6.     {
7.         Pass
8.         {
9.             ZTest Always Cull Off ZWrite Off
10.             Fog { Mode off }
11.  
12. CGPROGRAM
13. #pragma vertex vert
14. #pragma fragment frag
15. #pragma fragmentoption ARB_precision_hint_fastest
16.  
17. #include "UnityCG.cginc"
18.    
19.     struct v2f {
20.         float4 pos : POSITION;
21.         float2 uv : TEXCOORD0;
22.     };
23.    
24.     uniform sampler2D _MainTex;
25.    
26.     v2f vert( appdata_img v )
27.     {
28.         v2f o;
29.         o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
30.         o.uv = v.texcoord.xy;
31.         return o;
32.     }
33.    
34.     float4 frag(v2f i) : COLOR
35.     {
36.         float2 coords = i.uv;
37.         float4 pos = i.pos;
38.        
39.         // known constants for the particular lens and sensor
40.         float f = 368.28488;  // focal length
41.         float ox = 147.54834; // principal point, x axis
42.         float oy = 126.01673; // principal point, y axis
43.         float k1 = 0.4142;    // constant for radial distortion correction
44.         float k2 = 0.40348;
45.         float2 xy = (coords - float2(ox, oy))/float2(f,f);
46.        
47.         float r = sqrt(dot(xy,xy));
48.         float r2 = r * r;
49.         float r4 = r2 * r2;
50.         float coeff = (k1 * r2 + k2 * r4);
51.        
52.         // add the calculated offsets to the current texture coordinates
53.         xy = ((xy + xy * coeff.xx) * f.xx) + float2(ox, oy);
54.        
55.         // look up the texture at the corrected coordinates and output the color
56.         return texRECT(_MainTex, xy);      
57.     }
58.    
59.     ENDCG
60.    
61.         }
62.     }
63.  
64. Fallback off
65.    
66. }

And my associated script attached to the camera is as follows:

Code (csharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [ExecuteInEditMode]
5. [RequireComponent (typeof(Camera))]
6. [AddComponentMenu ("Image Effects/CameraUndistort")]
7.  
8. public class CameraUndistort : PostEffectsBase {
9.    
10.     public Shader CameraUndistortShader = null;
11.     public Material CameraUndistortMaterial = null;
12.    
13.     bool CheckResources (){
14.         CheckSupport (false);
15.         CameraUndistortMaterial = CheckShaderAndCreateMaterial(CameraUndistortShader,CameraUndistortMaterial);
16.         if(!isSupported)
17.             ReportAutoDisable ();
18.         return isSupported;        
19.     }
20.    
21.     void OnRenderImage (RenderTexture source, RenderTexture destination){      
22.         if(CheckResources()==false) {
23.             Graphics.Blit (source, destination);
24.             return;
25.         }
26.                
27.         Graphics.Blit (source, destination, CameraUndistortMaterial);  
28.     }
29. }

At the moment the result I get is my scene camera showing completely white. I've tried a number of alterations to both the shader and the script, but I'm obviously doing some things wrong. I may not be connecting the shader output with the material on the script or something like that. Any help would be much appreciated.

 

Check your pm, i sent you the solution.

 

I think im having the same problem. Could u send me the solution as well?

Thanks

 

I am also struggling with this issue. Could you help me out as well, or point me to the right direction, please? Thank You.

 

I've got a shader which is a little different to this script, but I also have the same problems. This shader renders a WebcamTexture and ever

 

The shader is a part of my "TOZ Image Effects" pack which is available in the assetstore.

 

I tried to find your pack from the asset store. it seems no longer available. Can you please let me know where to find it? Thank you!

 

It is one of the effects in my TOZ Image Effects pack.

 

Thank you for your reply! your package is very cool! I am wondering if you have shaders for the following segmentation effect, the segmentation depends on different material. If you have it, please let me know and I am willing to pay for it. Thank you! e.g.

 

I am not sure if i understand segmentation effect from the video, it just renders every object (group of objects) with different colors. And if thats the thing you need, its a simple shader. But if im missing something else here, let me know through private message and ill help.