al_fixasin(3alleg5)

💖 al_fixasin 💖

okay bestie, welcome to the Allegro 5 API corner of the manual, where we do trigonometry but make it fixed-point ✨

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🌸 SYNOPSIS 🌸

#include <allegro5/allegro.h>

al_fixed al_fixasin(al_fixed x);

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🦋 DESCRIPTION 🦋

so like. this function hands you the inverse sine of a value, and it does it with a lookup table because we're efficient like that 💅

the input has gotta be a fixed point value, no cap. and here's the tea: inverse sine only exists in the domain from -1 to 1. that's it, that's the whole vibe check. if you feed it anything outside that range, the function sets Allegro's errno to EDOM and returns zero. not a crash, not a guess — just a polite little nope 🙈

example time, periodt:

float angle;
al_fixed val;

/* Sets `val' to a right binary angle (64). */
val = al_fixasin(al_itofix(1));

/* Sets `angle' to 0.2405. */
angle = al_fixtof(al_fixmul(al_fixasin(al_ftofix(0.238)), al_fixtorad_r));

/* This will trigger the assert. */
val = al_fixasin(al_ftofix(-1.09));
assert(!al_get_errno());

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👑 RETURN VALUE 👑

it gives you back the inverse sine of that fixed point value, measured as a fixed point binary format angle 🎀 or, if your input was out of range, you get zero instead.

and the range on the way out? every single return value of this function lands between -64 and 64. iconic. consistent. we love a bounded queen ⭐

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🫶 quick recap bestie: fixed point in, -1 to 1 only, EDOM + zero if you stray, and the answer always comes home between -64 and 64. iykyk.

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this was the Allegro reference manual page for al_fixasin(3alleg5) — mwah, go forth and sine responsibly 💜✨