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