#include "tangent.h"

const BgcTangentFP32 BGC_IDLE_TANGENT_FP32 = { 1.0f, 0.0f };

const BgcTangentFP64 BGC_IDLE_TANGENT_FP64 = { 1.0, 0.0 };

void _bgc_tangent_normalize_fp32(const float square_modulus, _BgcDarkTwinTangentFP32* twin)
{
    // (square_modulus != square_modulus) is true when square_modulus is NaN

    if (square_modulus <= BGC_SQUARE_EPSYLON_FP32 || square_modulus != square_modulus) {
        twin->cos = 1.0f;
        twin->sin = 0.0f;
        return;
    }

    const float multiplier = sqrtf(1.0f / square_modulus);

    twin->cos *= multiplier;
    twin->sin *= multiplier;
}

void _bgc_tangent_normalize_fp64(const double square_modulus, _BgcDarkTwinTangentFP64* twin)
{
    // (square_modulus != square_modulus) is true when square_modulus is NaN

    if (square_modulus <= BGC_SQUARE_EPSYLON_FP64 || square_modulus != square_modulus) {
        twin->cos = 1.0;
        twin->sin = 0.0;
        return;
    }

    const double multiplier = sqrt(1.0 / square_modulus);

    twin->cos *= multiplier;
    twin->sin *= multiplier;
}