image effect shader causes black screen on android but working on pc.

i'm using an image effect shader that adds edge detection to all objects.
the shader works fine on pc and in editor. also in some android phones. but not all off them .
when the scene starts . the screen freezes and doesn't render anything .
when i change Blit type in android player setting from always to auto/never .
it works fine on all devices but the frame rate drops by 20 fps.

can anyone help me with this?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. [ExecuteAlways]
5. public class O_CustomImageEffect : MonoBehaviour {
6.     public Material imageEffect;
7.     RenderTexture myRenderTexture;
8.     private void OnRenderImage (RenderTexture source, RenderTexture destination) {
9.         if (imageEffect != null) {
10.             Graphics.Blit (source, destination, imageEffect);
11.         } else
12.             destination = source;
13.     }
14. }

Code (CSharp):

1. Shader "The Developer/SS Texture Based Outline"
2. {
3.     Properties
4.     {
5.         _OutlineColor("Outline Color", Color) = (1,1,1,1)
6.         _OutlineThreshold("Outline Threshold", Float) = 3
7.         _OutlineWidth("Outline Width", Float) = 2
8.         _EdgeStrengthen ("Edge Strengthen", Float) = 2
9.         _MainTex ("Texture", 2D) = "white" {}
10.     }
11.     SubShader
12.     {
13.         // No culling or depth
14.         // Cull Off ZWrite Off ZTest Always
15.         Pass
16.         {
17.             CGPROGRAM
18.             #pragma vertex vert
19.             #pragma fragment frag
20.             #include "UnityCG.cginc"
21.             struct appdata
22.             {
23.                 float4 vertex : POSITION;
24.                 float3 normal : NORMAL;
25.             };
26.             struct v2f
27.             {
28.                 float4 position : POSITION;
29.                 float4 screenPos : TEXCOORD0;
30.             };
31.             fixed4 _OutlineColor;
32.             half _OutlineThreshold;
33.             half _OutlineWidth;
34.             half _EdgeStrengthen;
35.             sampler2D _CameraDepthTexture;
36.             sampler2D _MainTex;
37.             v2f vert(appdata input)
38.             {
39.                 v2f output;
40.                 output.position = UnityObjectToClipPos(input.vertex);
41.                 output.screenPos = output.position;
42.                 return output;
43.             }
44.             #define PSL01UVC(tex, uv1, uv2) pow(\
45.                 (tex2D(tex, uv1) - tex2D(tex, uv2)) * _EdgeStrengthen, \
46.                 2)
47.             float4 outline;
48.             half4 pixel;
49.             half2 uv;
50.             half onePixelW, onePixelH;
51.             fixed i;
52.             void OutlinePixel(sampler2D tex){
53.                 outline = 0;
54.                 for(i = 1 ; i <= _OutlineWidth ; ++i)
55.                     outline +=
56.                             PSL01UVC(tex, half2(uv.x - i * onePixelW, uv.y),
57.                                           half2(uv.x + i * onePixelW, uv.y)) +
58.                             PSL01UVC(tex, half2(uv.x, uv.y + i * onePixelH),
59.                                           half2(uv.x, uv.y - i * onePixelH)) +
60.                             PSL01UVC(tex, half2(uv.x - i * onePixelW, uv.y - i * onePixelH),
61.                                           half2(uv.x + i * onePixelW, uv.y + i * onePixelH)) +
62.                             PSL01UVC(tex, half2(uv.x - i * onePixelW, uv.y + i * onePixelH),
63.                                           half2(uv.x + i * onePixelW, uv.y - i * onePixelH));
64.             }
65.             half4 frag(v2f input) : SV_Target
66.             {
67.                 uv = input.screenPos.xy / input.screenPos.w;
68.                 uv.x = (uv.x + 1) * .5;
69.                 uv.y = (uv.y + 1) * .5;
70.                 pixel = tex2D(_MainTex, uv);
71.                 onePixelW = 1.0 / _ScreenParams.x;
72.                 onePixelH = 1.0 / _ScreenParams.y;
73.                 OutlinePixel(_MainTex);
74.                 return lerp(pixel, _OutlineColor, (outline.r + outline.g + outline.b) >= _OutlineThreshold ? 1 : 0);
75.             }
76.             ENDCG
77.         }
78.     }
79. }

 

Problem solved by chaning the graphics api to this
View attachment 724483