Sin Approximation

SinApprox.h

// From: https://web.archive.org/web/20080228213915/http://www.devmaster.net/forums/showthread.php?t=5784

float sinApprox(float x)
{
    const float kPI32 = 3.14159265359f;
    const float B = 4/kPI32;
    const float C = -4/(kPI32*kPI32);

    float y = B * x + C * x * abs(x);

#ifdef EXTRA_PRECISION
    //const float Q = 0.775;
    const float P = 0.225;

    y = P * (y * abs(y) - y) + y;   // Q * y + P * y * abs(y)
#endif
    return y;
}