uniform float zNear;// = 0.1;
uniform float zFar;// = 500.0;

float mapRange(float x, float minIn, float maxIn, float minOut, float maxOut)
{
    x -= minIn;
    x = x * (maxOut - minOut) / (maxIn - minIn);
    x += minOut;
    x = clamp(x, minOut, maxOut);
    return x;
}

float linearDepth(float depthSample)
{
    depthSample = 2.0 * depthSample - 1.0;
    float zLinear = 2.0 * zNear * zFar / (zFar + zNear - depthSample * (zFar - zNear));
    return zLinear;
}

float adepthSample(float linearDepth)
{
    float nonLinearDepth = (zFar + zNear - 2.0 * zNear * zFar) / (linearDepth * (zFar - zNear));
    
    nonLinearDepth = (zFar + zNear - 2.0 * zNear * zFar / linearDepth) / (zFar - zNear);
    nonLinearDepth = (nonLinearDepth + 1.0) / 2.0;
    return nonLinearDepth;
}