Can any pro guide me on these 2 functions in the shader? what is the NEAR_Z and FAR_Z stand for, is the camera far and near value? how to get that in monogame?

float LinearDepth(float depth)

{

return (depth * NEAR_Z) / (FAR_Z - depth * (FAR_Z - NEAR_Z));

}

float ViewDepth(float depth)

{

return (FAR_Z * NEAR_Z) / (FAR_Z - depth * (FAR_Z - NEAR_Z));

}

float2 ProjectionConstants(float gNearZ, float gFarZ)

{

float2 projectionConstants;

projectionConstants.x = gFarZ / (gFarZ - gNearZ);

projectionConstants.y = (-gFarZ * gNearZ) / (gFarZ - gNearZ);

return projectionConstants;

}

float LinearZ(float4 outPosition)

{

float2 projectionConstants = ProjectionConstants(gNearZ, gFarZ);

float depth = outPosition.z / outPosition.w;

float linearZ = projectionConstants.y / (depth - projectionConstants.x);

return linearZ;

}