float PI = 3.14159265358979323846f;
float PI_2 = 1.57079632679489661923f;
float PI_4 = 0.785398163397448309616f;

float SQRT2 = 1.41421356237309504880f;

float3 CalculateViewDirection(float3 worldPos, float4x4 viewInverse)
{
    return normalize(worldPos - viewInverse[3].xyz);
}
