fixacos

NAME

fixacos − Fixed point inverse cosine lookup table. Allegro game programming library.

SYNOPSIS

#include <allegro.h>

fixed fixacos(fixed x);

DESCRIPTION

This function finds the inverse cosine of a value using a lookup table. The input value must be a fixed point radian. The inverse cosine is defined only in the domain from ‘-1’ to ‘1’. Outside of this input range, the function will set ‘errno’ to EDOM and return zero. Example:

fixed result;

/* Sets ‘result’ to binary angle 128. */
result = fixacos(itofix(-1));

RETURN VALUE

Returns the inverse sine of a fixed point value, measured as fixed point binary format angle, or zero if the input was out of range. All return values of this function will be in the range ‘0’ to ‘128’.

SEE ALSO