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/**
* Maths library: two factorials, integer power, wrappers for libultra's sins and coss (the main ones used), and some
* random functions moved from OoT's z_actor
*/
#include "global.h"
#include "rand.h"
static f32 sFactorialTbl[] = {
1.0f, 1.0f, 2.0f, 6.0f, 24.0f, 120.0f, 720.0f, 5040.0f, 40320.0f, 362880.0f, 3628800.0f, 39916800.0f, 479001600.0f,
};
/**
* Takes a float, returns the factorial of it(s trunctation), iteratively
* Unused
*
* @remark original name: "ffact"
*/
f32 Math_FactorialF(f32 n) {
f32 ret = 1.0f;
s32 i;
//! @bug No check for negative argument. Will return 1.0f if the argument truncates to a negative int.
for (i = n; i > 1; i--) {
ret *= i;
}
return ret;
}
/**
* Takes an int and returns its factorial as a float. Uses the lookup table for n <= 12.
* Unused
*
* @remark original name: "ifact"
*/
f32 Math_Factorial(s32 n) {
f32 ret;
s32 i;
//! @bug No check for negative argument. Will read the array out-of-bounds if the argument is negative.
//! (The OoT version does an unsigned check instead, which will return sFactorialTbl[12] for a negative argument.)
if (n >= ARRAY_COUNT(sFactorialTbl)) {
ret = sFactorialTbl[12];
for (i = 13; i <= n; i++) {
ret *= i;
}
} else {
ret = sFactorialTbl[n];
}
return ret;
}
/**
* Returns base^{exp} if exp is nonnegative and 1.0f otherwise.
* Unused
*
* @remark original name: "powi"
*/
f32 Math_PowF(f32 base, s32 exp) {
f32 ret = 1.0f;
while (exp > 0) {
exp--;
ret *= base;
}
return ret;
}
/**
* Takes an angle in radians and returns the sine.
*
* @remark original name: "sinf_table"
*/
f32 Math_SinF(f32 rad) {
return sins(RAD_TO_BINANG(rad)) * (1.0f / SHRT_MAX);
}
/**
* Takes an angle in radians and returns the cosine.
*
* @remark original name: "cosf_table"
*/
f32 Math_CosF(f32 rad) {
return coss(RAD_TO_BINANG(rad)) * (1.0f / SHRT_MAX);
}
/**
* Returns a pseudo-random floating-point number between 0.0f and scale. Originally in z_actor in OoT.
*/
f32 Rand_ZeroFloat(f32 scale) {
return Rand_ZeroOne() * scale;
}
/**
* Returns a pseudo-random floating-point number between (- scale / 2) and (scale / 2). Originally in z_actor in OoT.
*/
f32 Rand_CenteredFloat(f32 scale) {
return Rand_Centered() * scale;
}
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