circf(3G)							     circf(3G)

NAME    [Toc]    [Back]

     circf, circfi, circfs - draws a filled circle

C SPECIFICATION    [Toc]    [Back]

     void circf(x, y, radius)
     Coord x, y, radius;

     void circfi(x, y, radius)
     Icoord x, y, radius;

     void circfs(x, y, radius)
     Scoord x, y, radius;

     The routines above	are functionally the same even though the type
     declarations for the coordinates differ.

PARAMETERS    [Toc]    [Back]

     x	      expects the x coordinate of the center of	the filled circle
	      specified	in world coordinates.

     y	      expects the y coordinate of the center of	the filled circle
	      specified	in world coordinates.

     radius   expects the length of the	radius of the filled circle.

DESCRIPTION    [Toc]    [Back]

     circf draws a filled circle in the	x-y plane (z = 0).  To draw a circle
     in	a plane	other than the x-y plane, define the circle in the x-y plane
     and then rotate or	translate the circle. Note that	filled circles rotated
     outside the 2-D x-y plane appear as filled	ellipses.

     A circle is drawn as a single polygon, and	therefore inherits all
     properties	that affect the	drawing	of polygons.  These include the
     current color, writemask, fill pattern, shade model, polygon antialiasing
     mode, polygon scan	conversion mode, and subpixel mode.  Front-face	and
     back-face elimination work	correctly with filled circles, which are
     front-facing when viewed from the positive	z half-space.  Some polygon
     modes are applicable only if old-style scan conversion is defeated.  (See
     note below.)

     After circf executes, the graphics	position is undefined.

SEE ALSO    [Toc]    [Back]

     arcf, backface, bgnpolygon, circ, frontface, glcompat, polymode,
     polysmooth, scrsubdivide, setpattern, shademodel, subpixel

NOTES    [Toc]    [Back]

     By	default	circf draws a polygon using the	old-style scan conversion
     algorithm,	rather than the	point sampling algorithm used by bgnpolygon
     and endpolygon.  Point sampling is	preferred over old-style scan
     conversion	because	it has higher performance, it results in higherquality
 images when blending, logical operations, or stenciling are used,



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circf(3G)							     circf(3G)



     and it supports new rendering features such as texture mapping, fog, and
     antialiasing.  Call glcompat(GLC_OLDPOLYGON,0) to enable point sampling
     of	polygons generated by circf.

     The identifier of the function circf declared in gl/gl.h conflicts	with
     the identifier of the external variable circf declared in regexp.h.  If
     you need to include gl/gl.h and regexp.h in the same source file, embed
     the "#include <regexp.h>" statement, and all references to	the variable
     circf in the source file, with a "#define circf re_circf" and "#undef
     re_circf" pair of statements.


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