Magnification shader

I'm trying to get this magnification shader to work with the URP but I'm not sure what needs to change.

I would really appreciate any help!

Code (CSharp):

1. Shader "Custom/Magnification"
2. {
3.     Properties
4.     {
5.         _Magnification("Magnification", Float) = 1
6.     }
7.  
8.     SubShader
9.     {
10.         Tags{ "Queue" = "Transparent" "PreviewType" = "Plane" }
11.         LOD 100
12.  
13.         GrabPass{ "_GrabTexture" }
14.  
15.         Pass
16.             {
17.                 ZTest On
18.                 ZWrite Off
19.                 Blend One Zero
20.                 Lighting Off
21.                 Fog{ Mode Off }
22.  
23.             CGPROGRAM
24.             #pragma vertex vert
25.             #pragma fragment frag
26.  
27.             #include "UnityCG.cginc"
28.  
29.             struct appdata
30.             {
31.                 float4 vertex : POSITION;
32.             };
33.  
34.             struct v2f
35.             {
36.                 //our UV coordinate on the GrabTexture
37.                 float4 uv : TEXCOORD0;
38.                 //our vertex position after projection
39.                 float4 vertex : SV_POSITION;
40.             };
41.  
42.             sampler2D _GrabTexture;
43.             half _Magnification;
44.  
45.             v2f vert(appdata v)
46.             {
47.                 v2f o;
48.                 o.vertex = UnityObjectToClipPos(v.vertex);
49.                 //the UV coordinate of our object's center on the GrabTexture
50.                 float4 uv_center = ComputeGrabScreenPos(UnityObjectToClipPos(float4(0, 0, 0, 1)));
51.                 //the vector from uv_center to our UV coordinate on the GrabTexture
52.                 float4 uv_diff = ComputeGrabScreenPos(o.vertex) - uv_center;
53.                 //apply magnification
54.                 uv_diff /= _Magnification;
55.                 //save result
56.                 o.uv = uv_center + uv_diff;
57.                 return o;
58.             }
59.  
60.             fixed4 frag(v2f i) : COLOR
61.             {
62.                 return tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(i.uv));
63.             }
64.             ENDCG
65.         }
66.     }
67. }

 

There's no grabpass in URP anymore, I think you would have to use _CameraOpaqueTexture which (afaik) is similar to the grabpass functionality.

Maybe you could remake this as a Shader Graph? You can access Scene Color in Shader Graph which provides you that same camera image.

 

Did you manage to pull this off? Im looking for a magnification shader for URP for 3 years

 

Three years? Surely you already tried to sample the Scene Color in the Shader Graph during those three years?

You could just manipulate the UV coordinates (resize UVs) and then perform the sampling and finally render the sampled image to the magnifying glass surface. This setup could produce something like this (I just did a quick test.):

 

Very nice! Thank you

 

What worked for me was swapping the Screen Position node to the Camera.Position node