Deg_Trig_Sample.h

#ifndef DEG_TRIG_H
#define DEG_TRIG_H
#include <math.h>

#define _USE_MATH_DEFINES
#define RAD_TO_DEG(x) (x)*(180.0/M_PI)
#define DEG_TO_RAD(x) (x)*(M_PI/180.0)

// FLOAT FUNCTIONS

float my_atan2f_PIx2_rads(float y, float x)
{
    float rads;
    rads = atan2f(y, x);
    if(rads < 0.0f)
        rads += (M_PI * 2);
    return rads;
}

float my_atan2f_deg(float y, float x)
{
    float rads;
    float degs;
    rads = atan2f(y, x);
    if(rads < 0.0f)
        rads += (M_PI * 2);
    degs = RAD_TO_DEG(rads);
    /*if(degs < 0.0f) // Optional method
        degs += 360.0f;*/
    return degs;
}

float my_cosf_deg(float deg)
{
    // It might also be a good idea to handle degs < -180º
    float rads;
    float new_degs = deg;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return cosf(rads);
}

float my_sinf_deg(float deg)
{
    float rads;
    float new_degs = deg;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return sinf(rads);
}

float my_tanf_deg(float deg)
{
    float rads;
    float new_degs = deg;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return tanf(rads);
}

// NOD - North Orientated Display

float my_nod_atan2f_deg(float y, float x)
{
    float rads;
    float degs;
    rads = atan2f(y, x);
    if(rads < 0.0f)
        rads += (M_PI * 2);
    degs = RAD_TO_DEG(rads);
    if(degs >= 0.0f && degs <= 360.0f)
        degs += 90.0f;
    if(degs > 360.0f)
        degs -= 360.0f;

    return degs;
}

float my_nod_cosf_deg(float deg)
{
    float rads;
    float new_degs = deg;
    new_degs -= 90;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return cosf(rads);
}

float my_nod_sinf_deg(float deg)
{
    float rads;
    float new_degs = deg;
    new_degs -= 90;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return sinf(rads);
}

// DOUBLE FUNCTIONS (not overloaded)

double my_atan2d_PIx2_rads(double y, double x)
{
    double rads;
    rads = atan2f(y, x);
    if(rads < 0.0f)
        rads += (M_PI * 2);
    return rads;
}

double my_atan2d_deg(double y, double x)
{
    double rads;
    double degs;
    rads = atan2f(y, x);
    if(rads < 0.0f)
        rads += (M_PI * 2);
    degs = RAD_TO_DEG(rads);
    /*if(degs < 0.0f) // Optional method
        degs += 360.0f;*/
    return degs;
}

double my_cosd_deg(double deg)
{
    double rads;
    double new_degs = deg;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return cosf(rads);
}

double my_sind_deg(double deg)
{
    double rads;
    double new_degs = deg;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return sinf(rads);
}

double my_tand_deg(double deg)
{
    double rads;
    double new_degs = deg;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return tanf(rads);
}

// NOD - North Orientated Display

double my_nod_atan2d_deg(double y, double x)
{
    double rads;
    double degs;
    rads = atan2f(y, x);
    if(rads < 0.0f)
        rads += (M_PI * 2);
    degs = RAD_TO_DEG(rads);
    if(degs >= 0.0f && degs <= 360.0f)
        degs += 90.0f;
    if(degs > 360.0f)
        degs -= 360.0f;

    return degs;
}

double my_nod_cosd_deg(double deg)
{
    double rads;
    double new_degs = deg;
    new_degs -= 90;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return cosf(rads);
}

double my_nod_sind_deg(double deg)
{
    double rads;
    double new_degs = deg;
    new_degs -= 90;
    while(new_degs > 180.0f)
        new_degs -= 360.0f;
    rads = DEG_TO_RAD(new_degs);
    return sinf(rads);
}

// TODO:
// acos(), asin(), secant?
#endif