# How to convert depth values into Unity's distance

I am new in Unity and now only studying for my work project. I need help with computing real distances from depth values. Can't figure it out. My shader is:

Shader "Custom/MyDepthShader"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}

}
{
// No culling or depth
Cull Off ZWrite Off ZTest Always

Pass
{
CGPROGRAM
#pragma vertex vert // compile function vert as vertex shader
#pragma fragment frag // compile function frag as fragment shader

#include "UnityCG.cginc"

struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};

struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};

v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = v.uv;
return o;
}

sampler2D _MainTex;

fixed4 frag (v2f i) : SV_Target
{
depth = Linear01Depth(depth);
depth = depth * _ProjectionParams.z;
return depth;
}
ENDCG
}
}
}


I Blit then these values from renderTexture to texture2D and use function GetPixel(i,j). Knowing, that a cube is at 1.5 units distance from camera I can't get this value from depth texture. Thank you for your help. Now I suspect that I have got distance values, but they are biased by 0.5 for some reason... Can anyone explain this as well?

I found how to get distances from depth texture, so basically I can answer this question, but there is still unexplained bias in measurements.

As described in the docs, Linear01Depth() is for getting the depth as a fraction of the way between the near and far planes.
To get an eye space depth value in world units, you want LinearEyeDepth()