Merge pull request #120 from suve/add-sdlstdinc-math-functions

Add sdlstdinc math functions

This patch adds the cstdlib-like math functions found in SDL_stdinc.h. The doc-comments are based on Linux man-pages and research into SDL's git history.

Author: Free-Pascal-meets-SDL-Website

units/sdl2.pas

@@ -259,7 +259,6 @@ function SDL_FRectEmpty(const r: PSDL_FRect): Boolean;
   Result := (r = NIL) or (r^.w <= cfloat(0.0)) or (r^.h <= cfloat(0.0))
 end;
 
-{ FIXME: This the Pascal System.Abs() function, instead of the C SDL_fabsf() function. }
 function SDL_FRectEqualsEpsilon(const a, b: PSDL_FRect; const epsilon: cfloat): Boolean;
 begin
   Result :=
@@ -269,13 +268,13 @@ function SDL_FRectEqualsEpsilon(const a, b: PSDL_FRect; const epsilon: cfloat):
       (a = b)
       or
       (
-        (Abs(a^.x - b^.x) <= epsilon)
+        (SDL_fabsf(a^.x - b^.x) <= epsilon)
         and
-        (Abs(a^.y - b^.y) <= epsilon)
+        (SDL_fabsf(a^.y - b^.y) <= epsilon)
         and
-        (Abs(a^.w - b^.w) <= epsilon)
+        (SDL_fabsf(a^.w - b^.w) <= epsilon)
         and
-        (Abs(a^.h - b^.h) <= epsilon)
+        (SDL_fabsf(a^.h - b^.h) <= epsilon)
       )
     )
 end;