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Fixed bug 2245 - add SDL_acos and SDL_asin 

Sylvain

Here's some code to add arc cosine, and arc sin functions to SDL_stdlib.c
There are plainly written using SDL_atan.
This commit is contained in:
Sam Lantinga 2013-11-16 18:56:02 -08:00
parent 923709a699
commit e4146267fa
2 changed files with 28 additions and 0 deletions
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2
include/SDL_stdinc.h
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@ -340,6 +340,8 @@ extern DECLSPEC int SDLCALL SDL_vsnprintf(char *text, size_t maxlen, const char
#endif #endif
#endif #endif
extern DECLSPEC double SDLCALL SDL_acos(double x);
extern DECLSPEC double SDLCALL SDL_asin(double x);
extern DECLSPEC double SDLCALL SDL_atan(double x); extern DECLSPEC double SDLCALL SDL_atan(double x);
extern DECLSPEC double SDLCALL SDL_atan2(double x, double y); extern DECLSPEC double SDLCALL SDL_atan2(double x, double y);
extern DECLSPEC double SDLCALL SDL_ceil(double x); extern DECLSPEC double SDLCALL SDL_ceil(double x);

26
src/libm/s_atan.c
View File

@ -112,3 +112,29 @@ double atan(double x)
} }
} }
libm_hidden_def(atan) libm_hidden_def(atan)
double SDL_acos(double val)
{
double result;
if (val == -1.0) {
result = M_PI;
} else {
result = SDL_atan(SDL_sqrt(1.0 - val * val) / val);
if (result < 0.0)
{
result += M_PI;
}
}
return result;
}
double SDL_asin(double val)
{
double result;
if (val == -1.0) {
result = -(M_PI / 2.0);
} else {
result = (M_PI / 2.0) - SDL_acos(val);
}
return result;
}