flightgear/src/FDM/YASim/Math.cpp

#include <math.h>

#include "Math.hpp"
namespace yasim {

float Math::clamp(float val, float min, float max)
{
    if(val < min) return min;
    if(val > max) return max;
    return val;
}

float Math::abs(float f)
{
    return (float)::fabs(f);
}

float Math::sqrt(float f)
{
    return (float)::sqrt(f);
}

float Math::ceil(float f)
{
    return (float)::ceil(f);
}

float Math::acos(float f)
{
    return (float)::acos(f);
}

float Math::asin(float f)
{
    return (float)::asin(f);
}

float Math::cos(float f)
{
    return (float)::cos(f);
}

float Math::sin(float f)
{
    return (float)::sin(f);
}

float Math::tan(float f)
{
    return (float)::tan(f);
}

float Math::atan(float f)
{
    return (float)::atan(f);
}

float Math::atan2(float y, float x)
{
    return (float)::atan2(y, x);
}

double Math::floor(double x)
{
    return ::floor(x);
}

double Math::abs(double f)
{
    return ::fabs(f);
}

double Math::sqrt(double f)
{
    return ::sqrt(f);
}

float Math::pow(double base, double exp)
{
    return (float)::pow(base, exp);
}

double Math::ceil(double f)
{
    return ::ceil(f);
}

double Math::cos(double f)
{
    return ::cos(f);
}

double Math::sin(double f)
{
    return ::sin(f);
}

double Math::tan(double f)
{
    return ::tan(f);
}

double Math::atan2(double y, double x)
{
    return ::atan2(y, x);
}

void Math::set3(float* v, float* out)
{
    out[0] = v[0];
    out[1] = v[1];
    out[2] = v[2];
}

float Math::dot3(float* a, float* b)
{
    return a[0]*b[0] + a[1]*b[1] + a[2]*b[2];
}

void Math::mul3(float scalar, float* v, float* out)
{
    out[0] = scalar * v[0];
    out[1] = scalar * v[1];
    out[2] = scalar * v[2];
}

void Math::add3(float* a, float* b, float* out)
{
    out[0] = a[0] + b[0];
    out[1] = a[1] + b[1];
    out[2] = a[2] + b[2];
}

void Math::sub3(float* a, float* b, float* out)
{
    out[0] = a[0] - b[0];
    out[1] = a[1] - b[1];
    out[2] = a[2] - b[2];
}

float Math::mag3(float* v)
{
    return sqrt(dot3(v, v));
}

void Math::unit3(float* v, float* out)
{
    float imag = 1/mag3(v);
    mul3(imag, v, out);
}

void Math::cross3(float* a, float* b, float* out)
{
    float ax=a[0], ay=a[1], az=a[2];
    float bx=b[0], by=b[1], bz=b[2];
    out[0] = ay*bz - by*az;
    out[1] = az*bx - bz*ax;
    out[2] = ax*by - bx*ay;
}

void Math::mmul33(float* a, float* b, float* out)
{
    float tmp[9];
    tmp[0] = a[0]*b[0] + a[1]*b[3] + a[2]*b[6];
    tmp[3] = a[3]*b[0] + a[4]*b[3] + a[5]*b[6];
    tmp[6] = a[6]*b[0] + a[7]*b[3] + a[8]*b[6];

    tmp[1] = a[0]*b[1] + a[1]*b[4] + a[2]*b[7];
    tmp[4] = a[3]*b[1] + a[4]*b[4] + a[5]*b[7];
    tmp[7] = a[6]*b[1] + a[7]*b[4] + a[8]*b[7];

    tmp[2] = a[0]*b[2] + a[1]*b[5] + a[2]*b[8];
    tmp[5] = a[3]*b[2] + a[4]*b[5] + a[5]*b[8];
    tmp[8] = a[6]*b[2] + a[7]*b[5] + a[8]*b[8];

    int i;
    for(i=0; i<9; i++)
	out[i] = tmp[i];
}

void Math::vmul33(float* m, float* v, float* out)
{
    float x = v[0], y = v[1], z = v[2];
    out[0] = x*m[0] + y*m[1] + z*m[2];
    out[1] = x*m[3] + y*m[4] + z*m[5];
    out[2] = x*m[6] + y*m[7] + z*m[8];
}

void Math::tmul33(float* m, float* v, float* out)
{
    float x = v[0], y = v[1], z = v[2];
    out[0] = x*m[0] + y*m[3] + z*m[6];
    out[1] = x*m[1] + y*m[4] + z*m[7];
    out[2] = x*m[2] + y*m[5] + z*m[8];
}

void Math::invert33(float* m, float* out)
{
    // Compute the inverse as the adjoint matrix times 1/(det M).
    // A, B ... I are the cofactors of a b c
    //                                 d e f
    //                                 g h i
    float a=m[0], b=m[1], c=m[2];
    float d=m[3], e=m[4], f=m[5];
    float g=m[6], h=m[7], i=m[8];

    float A =  (e*i - h*f);
    float B = -(d*i - g*f);
    float C =  (d*h - g*e);
    float D = -(b*i - h*c);
    float E =  (a*i - g*c);
    float F = -(a*h - g*b);
    float G =  (b*f - e*c);
    float H = -(a*f - d*c);
    float I =  (a*e - d*b);

    float id = 1/(a*A + b*B + c*C);

    out[0] = id*A; out[1] = id*D; out[2] = id*G;
    out[3] = id*B; out[4] = id*E; out[5] = id*H;
    out[6] = id*C; out[7] = id*F; out[8] = id*I;     
}

void Math::trans33(float* m, float* out)
{
    // 0 1 2   Elements 0, 4, and 8 are the same
    // 3 4 5   Swap elements 1/3, 2/6, and 5/7
    // 6 7 8
    out[0] = m[0];
    out[4] = m[4];
    out[8] = m[8];

    float tmp = m[1];
    out[1] = m[3];
    out[3] = tmp;

    tmp = m[2];
    out[2] = m[6];
    out[6] = tmp;

    tmp = m[5];
    out[5] = m[7];
    out[7] = tmp;
}

void Math::ortho33(float* x, float* y,
                   float* xOut, float* yOut, float* zOut)
{
    float x0[3], y0[3];
    set3(x, x0);
    set3(y, y0);

    unit3(x0, xOut);
    cross3(xOut, y0, zOut);
    unit3(zOut, zOut);
    cross3(zOut, xOut, yOut);
}

}; // namespace yasim