Amiga Driver Document
  Author: Dr. Charles E. Campbell, Jr.


  The Amiga/Vogl Screen and Window

    The amiga driver opens a screen and a window
    with the following default properties:

    	a full size screen (based on your workbench screen size)
    	four bitplanes (ie. 16 colors)
    	single buffer mode
    	high resolution
    	interlaced
        borderless window


  Optional Configuration

    You may call AMIGA_config(char *config) prior to calling
    winopen() to modify the default screen configuration.  The
    configuration string is composed of single letter "commands":

        b = give window a border
    	d = double buffer mode
    	e = extra halfbrite mode
    	h = ham mode
    	s = single buffer mode (default)
    	1 = one bit plane
    	2 = two bit planes
    	3 = three bit planes
    	4 = four bit planes
    	5 = five bit planes

    If the window is not borderless, then vogl's

        winopen(char *title)

    function will yield a titled window.


  Amiga/Vogl Graphics Data Structures

    The vogl winopen() calls upon AMIGA_init() to initialize
    graphics on the amiga.  The AMIGA_init() function sets
    up data structures in chip memory which the programmer
    may use for his/her own purposes.
 
    	WORD                 *voglareaBuffer
    	struct BitMap        *voglback
    	struct BitMap        *voglfront
    	struct DiskFontBase  *DiskfontBase
    	struct GfxBase       *GfxBase
    	struct IntuiText     *voglitext
    	struct IntuitionBase *IntuitionBase
    	struct IOStdReq      *vogl_cd_ioreq
    	struct Library       *ConsoleDevice
    	struct RastPort      *voglrastport
    	struct Screen        *voglscreen
    	struct TextAttr      *vogltextattr
    	struct TmpRas        *vogltmpras
    	struct Window        *voglwindow

    Thus, this amiga driver could be used directly rather
    than via vogl, as all of the important variables are
    globally visible.

    The AMIGA_exit() function cleans up all of the memory
    allocated by AMIGA_init().


  Hershey Fonts

    The Hershey font functions have been fixed for the
    Amiga so that they, too, are available.  All of the
    programs in the examples directory have been compiled
    and tested.


  Hardware Fonts

    The Amiga/Vogl hardware font loader (AMIGA_font) uses
    the following convention to specify fonts:

        fontname;height[;{BEIPU}]

    The fontname and height are required; the modifiers (BEIPU)
    are not.  The modifiers' meanings are:

        B == bold
        E == extended
        I == italic
        P == plain (default)
        U == underlined

    Vogl starts up with two fonts: the "small" hardware font
    (id of 0) and the "large" hardware font (id of 1).  The Amiga/vogl
    driver initializes these fonts to:

        small hardware font: "topaz;9;P"
        large hardware font: "topaz;11;P"

    For whatever reason, Vogl typically allows only one font.  The
    winopen()/ginit() functions set

        vdevice.maxfontnum = 2

    To use more Amiga fonts, you'll need to change vdevice.maxfontnum
    and to load the fonts using AMIGA_fontname(char *fontspec)
    directly.  Obviously, this stratagem will not port to GL or other
    Vogl platforms.  The AMIGA_fontname() function was designed to
    handle an arbitrary quantity of fonts.  This function only
    loads new fonts as needed; already loaded fonts are re-used
    properly.