Android RenderTexture format depth, sampler failed on android/ios gles.

Unity Engine
1

I wanna to use a RenderTexture ,format Depth, on Android/IOS . As I already use lightmap soft in scene., so I cann’t use Camera.depthTextureMode = DepthTextureMode.Depth , for that gonna cause a depth texture conflict. So I have to user RenderTexture, format Depth instead .
So I rendered a debug depth texture, that works well on PC , but faied on mobile device. :frowning: I know that gles use ARB_Format for depth texture, did I sample it wrong?
I just use “tex2D(_DepthTexture, i.uv).r” .
my shader :

Shader "Image Effects/Fog of War"
{
    Properties
    {
        _MainTex ("Base (RGB)", 2D) = "white" {}
    }
    SubShader
    {
        Pass
        {
            ZTest Always
            Cull Off
            ZWrite Off
            Fog { Mode off }
                  
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
sampler2D _MainTex;
sampler2D _DepthTexture;

uniform float4x4 _InverseMVP;
uniform float _Ratio;

struct Input
{
    float4 position : POSITION;
    float2 uv : TEXCOORD0;
};

Input vert (appdata_full v)
{
    Input o;
    o.position = mul(UNITY_MATRIX_MVP, v.vertex);
    o.uv = v.texcoord.xy;
    return o;
}

float3 CamToWorld (in float2 uv, in float depth)
{
    float4 pos = float4(uv.x, uv.y, depth, 1.0);
    pos.xyz = pos.xyz * 2.0 - 1.0;
    pos = mul(_InverseMVP, pos);
    return pos.xyz / pos.w;
}

fixed4 frag (Input i) : COLOR
{
    half4 original = tex2D(_MainTex, i.uv);   
//    return original;
//#if SHADER_API_D3D9||SHADER_API_D3D10||SHADER_API_D3D11
//    float2 depthUV = i.uv;
//    //depthUV.y = lerp(depthUV.y, 1.0 - depthUV.y, _CamPos.w);
//    //depthUV.y = 1.0 - depthUV.y;
//    float depth = tex2D(_DepthTexture, depthUV).r;
//    float3 pos = CamToWorld(depthUV, depth);
//    float4 debug = float4(pos.z*0.05,pos.z*0.05,pos.z*0.05,1);
//    return debug;
//#else
    float depth = tex2D(_DepthTexture, i.uv).r;
    float3 pos = CamToWorld(i.uv, depth);
    float4 debug = float4(pos.z*_Ratio,pos.z*_Ratio,pos.z*_Ratio,1);
    return debug;
//#endif
}

ENDCG
        }
    }
    Fallback off
}
2

I build a debug sample proj ,to render the depth sample of a cub , on the screen. You can see , that works fine in Editor, but fails on mobile devices.

depth test screen image:

proj link:

3

if attached image is what it should look like then it worked for me if i changed
sampler2D _DepthTexture;
to
sampler2D_float _DepthTexture;
if it doesnt help, we need more details