73 lines
1.2 KiB
C++
73 lines
1.2 KiB
C++
#include "math.h"
|
|
|
|
float Math::inv_sqrt(const float x) {
|
|
return (float)(1.0 / ::sqrtf(x));
|
|
}
|
|
|
|
float Math::fast_inv_sqrt(const float number) {
|
|
long i;
|
|
float x2, y;
|
|
const float threehalfs = 1.5F;
|
|
|
|
x2 = number * 0.5F;
|
|
y = number;
|
|
i = *(long *)&y;
|
|
i = 0x5f3759df - (i >> 1);
|
|
y = *(float *)&i;
|
|
y = y * (threehalfs - (x2 * y * y));
|
|
|
|
return y;
|
|
}
|
|
|
|
float Math::is_equal_approx(const float a, const float b) {
|
|
if (a + EPSILON < b && a - EPSILON > b) {
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
float Math::is_zero_approx(const float a) {
|
|
if (a + EPSILON < 0 && a - EPSILON > 0) {
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void Math::seed(const unsigned int s) {
|
|
srand(s);
|
|
}
|
|
|
|
void Math::randomize() {
|
|
srand(time(NULL));
|
|
}
|
|
|
|
int Math::rand() {
|
|
return ::rand();
|
|
}
|
|
|
|
float Math::randf() {
|
|
return ::rand() / static_cast<float>(RANDOM_32BIT_MAX);
|
|
}
|
|
|
|
double Math::randd() {
|
|
return ::rand() / static_cast<double>(RANDOM_32BIT_MAX);
|
|
}
|
|
|
|
int Math::rand(const int m) {
|
|
return rand() % m;
|
|
}
|
|
|
|
int Math::rand(const int from, const int to) {
|
|
return (rand() % (to - from)) + from;
|
|
}
|
|
|
|
float Math::rand(const float from, const float to) {
|
|
return randf() * (to - from) + from;
|
|
}
|
|
|
|
float Math::rand(const double from, const double to) {
|
|
return randd() * (to - from) + from;
|
|
}
|